Agenda — Adelanto City Council, June 10, 2026 (part 3 of 4)

WHEREAS, Section 10652 of the California Water Code provides that the California Environmental Quality Act (Division 13 (commencing with Section 21000) of the Public Resources Code (CEQA) does not apply to the preparation and adoption of the UWMP and the WSCP.

NOW, THEREFORE BE IT RESOLVED, the Adelanto Public Utility Authority Board of Directors does hereby resolve as follows:

Section 1. The Adelanto Public Utility Authority Board of Directors authorizes the adoption of its 2025 Urban Water Management Plan and its 2021 Water Shortage Continency Plan and orders the filing of the Plans with the California Department of Water Resources.

Section 2. The Adelanto Public Utility Authority is further authorized, in accordance with Water Code section 10621(d) and 10644(a)(I)(2), to make the adopted Plans available for public review at the Adelanto Governmental Center and on the City of Adelanto website, and to submit a copy of the Plans to the California State Library, and to any city or county within which the Authority provides water supplies no later than thirty (30) days after adoption.

Section 2. The Adelanto Public Utility Authority is further authorized to implement the Water Conservation Programs as set forth in the 2025 Urban Water Management Plan with recommendations regarding necessary procedures, rules, and regulations to carry out effective and equitable water conservation and water recycling programs.

Section 3. The Adelanto Public Utility Authority is further authorized to declare a Water Shortage Emergency according to the Water Shortage Levels and Triggers indicated in the Water Shortage Contingency Plan, implement necessary elements of said Plan, and recommend additional regulations to carry out effective and equitable allocation of water resources.

PASSED, APPROVED AND ADOPTED at a regular meeting of the Board of the Adelanto Public Utilities Authority held on June 10th day of June 2026 ___________________________
Gabriel Reyes, President
____________________________
Brenda Lopez, Secretary
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APUA Resolution No. 26-01

Page 3 ends

I, Brenda Lopez, City Clerk of the City of Adelanto, California, do hereby certify that the foregoing Resolution No. 06-01 was duly and regularly adopted at a special meeting of the City Council of the City of Adelanto on this 10th day of June 2026 be the following vote to wit:

AYES:

NOES:

ABSENT:

ABSTAIN:

IN WITNESS THEREOF, I hereunto set my hand and affix the official seal of the City of Adelanto on the 10th day of June 2026.
______________________________
Brenda Lopez, Secretary
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NOTICE OF PUBLIC HEARINGS
ON THE 2025 MOJAVE REGIONAL URBAN WATER MANAGEMENT PLAN NOTICE IS HEREBY GIVEN that the Mojave Water Agency (MWA) and the ten urban water suppliers participating in the 2025 Mojave Regional Urban Water Management Plan (2025 RUWMP), as listed in Table 1, will hold public hearings to receive comments on the proposed 2025 RUWMP, including each participating agency’s specific chapter contained within the 2025 RUWMP and each agency’s Water Shortage Contingency Plan (WSCP).

The 2025 RUWMP is a regional planning document prepared collaboratively by MWA and participating urban water suppliers within the Mojave Region in accordance with the California Urban Water Management Planning Act.

The 2025 RUWMP includes:
• Regional chapters addressing Region-wide water supplies, water demands, and water service reliability;
• A chapter addressing MWA’s role as the Region’s wholesale water supplier, including its water supply and management responsibilities; and
• Retailer-specific chapters for each participating urban water supplier.

Each retailer-specific chapter addresses conditions within the respective agency’s service area, including water service and system description, population and land use, water supply and infrastructure, water use characterization, water conservation and shortage response, and water system reliability. Each participating agency’s WSCP describes the actions that may be implemented to respond to water shortage conditions and maintain water service reliability within its service area.

The urban water suppliers participating in the 2025 RUWMP, along with their respective public hearing dates and proposed dates to consider adoption, are presented in Table 1. 362
TABLE 1: PARTICIPATING AGENCIES AND HEARING INFORMATION Agency Public Hearing Adoption
Hesperia Water District May 19th 2026
Hi-Desert Water District June 3rd 2026
Joshua Basin Water District June 3rd 2026
Golden State Water Company - Barstow May 27th 2026
Liberty Utilities - Apple Valley June 4th 2026
San Bernardino County Service Area 64 June 23rd 2026
San Bernardino County Service Area 70J June 23rd 2026
Phelan Pinion Hills CSD June 10th 2026
City of Adelanto Water District June 10th 2026
Mojave Water Agency June 11th 2026
Victorville Water District June 16th 2026
Each participating agency will hold its own public hearing to consider adoption of the 2025 RUWMP as it applies to its service area, including the applicable regional chapters, its respective retailerspecific chapter, its WSCP and all applicable appendices. MWA will separately consider adoption of the entirety of the 2025 RUWMP and its WSCP.

Draft documents will be made available in advance of each agency’s public hearing in accordance with applicable noticing requirements. At the time of the hearing, all interested parties may appear and provide comments.

Hesperia Water District
The Hesperia Water District will hold a public hearing as follows:

Date: May 19, 2026
Time: 6:30 PM
Location: City Council Chambers 9700 Seventh Ave., Hesperia CA, 92345 Copies of the draft 2025 RUWMP, including the Hesperia Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at 9700 Seventh Ave., Hesperia CA, 92345 during regular business hours and online at https://hesperia.legistar.com/Calendar.aspx
363
Hi-Desert Water District
The Hi-Desert Water District will hold a public hearing as follows:

Date: June 3, 2026
Time: 4:00 PM
Location: 55439 29 Palms Highway Yucca Valley, CA 92284 Copies of the draft 2025 RUWMP, including the Hi-Desert Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at 55439 29 Palms Highway Yucca Valley, CA 92284 during regular business hours and online at www.hdwd.com Joshua Basin Water District
The Joshua Basin Water District will hold a public hearing as follows:

Date: June 3, 2026
Time: 5:00 PM
Location: 61750 Chollita Road Joshua Tree CA 92252
Copies of the draft 2025 RUWMP, including the Joshua Basin Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at 61750 Chollita Rd., Joshua Tree, CA during regular business hours and online at www.jbwd.com Golden State Water Company – Barstow
Golden State Water Company – Barstow will hold a public hearing as follows:

Date: May 27, 2026
Time: 11:00 AM
Location: https://us06web.zoom.us/j/81445290033?pwd=UijEvrIofbbXI4bRWJDhDO3PRaXi0J.1 Passcode: 757372
Copies of the draft 2025 RUWMP, including the Golden State Water Company – Barstow retailerspecific chapter and the Company’s WSCP and applicable appendices, will be available for public review online at https://www.gswater.com/
Liberty Utilities – Apple Valley
Liberty Utilities – Apple Valley will hold a public hearing as follows:

Date: June 4, 2026
Time: 9:00 AM
Location: https://teams.microsoft.com/meet/284381397435981?p=HKnYB1DhSKyacIZB6S Passcode: uc3Ee7km
Copies of the draft 2025 RUWMP, including the Liberty Utilities – Apple Valley retailer-specific chapter and Liberty Utilities – Apple Valley WSCP and applicable appendices, will be available for public review online at https://libertyutilities.com/
364
San Bernardino County Service Area 64
The San Bernardino County Service Area 64 will hold a public hearing as follows:

Date: June 23, 2026
Time: 10:00 AM
Location: 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 Copies of the draft 2025 RUWMP, including the San Bernardino County Service Area 64 retailerspecific chapter and the CSA’s WSCP and applicable appendices, will be available for public review at 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 during regular business hours and online at https://sanbernardino.legistar.com/Calendar.aspx San Bernardino County Service Area 70J
The San Bernardino County Service Area 70J will hold a public hearing as follows:

Date: June 23, 2026
Time: 10:00 AM
Location: 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 Copies of the draft 2025 RUWMP, including the San Bernardino County Service Area 70J retailerspecific chapter and the CSA’s WSCP and applicable appendices, will be available for public review at 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 during regular business hours and online at https://sanbernardino.legistar.com/Calendar.aspx Phelan Pinion Hills Community Services District
The Phelan Pinion Hills Community Services District will hold a public hearing as follows:

Date: June 10, 2026
Time: 5:00 PM
Location: 4176 Warbler Road, Phelan, CA 92371
Copies of the draft 2025 RUWMP, including the Phelan Pinion Hills Community Services District retailer-specific chapter and the CSD’s WSCP and applicable appendices, will be available for public review at 4176 Warbler Road, Phelan, CA 92371 during regular business hours and online at www.pphcsd.org
365
City of Adelanto Water District
The City of Adelanto Water District will hold a public hearing as follows:

Date: June 10, 2026
Time: 11:00 AM
Location: Stadium - Conference Room 12000 Stadium Way Adelanto, CA, 92301 Copies of the draft 2025 RUWMP, including the City of Adelanto Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at 11600 Air Expressway Adelanto, CA 92301 during regular business hours and online at https://adelantoca.gov/services/water_sewer/index.php
Mojave Water Agency
The Mojave Water Agency will hold a public hearing as follows:

Date: June 11, 2026
Time: 9:30 AM
Location: MWA Board Room 13846 Conference Center Drive Apple Valley, CA 92307 Copies of the draft 2025 RUWMP and the Agency’s WSCP and applicable appendices, will be available for public review at 13846 Conference Center Drive Apple Valley, CA 92307 during regular business hours and online at https://www.mojavewater.org/about-mwa/agencycalendar/meetings/ Victorville Water District
The Victorville Water District will hold a public hearing as follows:

Date: June 16, 2026
Time: 6:00 PM
Location: City Hall 14343 Civic Drive Victorville, CA 92392 Copies of the draft 2025 RUWMP, including the Victorville Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at City Hall 14343 Civic Drive Victorville, CA 92392 during regular business hours and online at https://www.victorvilleca.gov/Government/City-Departments/City-Clerk/Agendas-MeetingsMinutes 366
NOTICE IS HEREBY GIVEN that the Mojave Water Agency
(MWA) and the ten urban water suppliers participating in the 2025 Mojave Regional Urban Water Management Plan
(2025 RUWMP), as listed below, will hold public hearings to receive comments on the proposed 2025 RUWMP, including each participating agency’s specific chapter contained within the 2025 RUWMP and each agency’s Water Shortage
Contingency Plan (WSCP). The 2025 RUWMP is a regional
planning document prepared collaboratively by MWA and
participating urban water suppliers within the Mojave
Region in accordance with the California Urban Water
Management Planning Act.

The 2025 RUWMP includes:
• Regional chapters addressing Region-wide water
supplies, water demands, and water service reliability; • A chapter addressing MWA’s role as the Region’s
wholesale water supplier, including its water supply
and management responsibilities; and
• Retailer-specific chapters for each participating urban water supplier.

Each retailer-specific chapter addresses conditions within the respective agency’s service area, including water service and system description, population and land use, water
supply and infrastructure, water use characterization, water conservation and shortage response, and water system
reliability. Each participating agency’s WSCP describes the actions that may be implemented to respond to water shortage conditions and maintain water service reliability within its service area. The urban water suppliers participating in the 2025 RUWMP, along with their respective public hearing dates are presented below.

Each participating agency will hold its own public hearing to consider adoption of the 2025 RUWMP as it applies to its service area, including the applicable regional chapters, its respective retailer-specific chapter, its WSCP and all applicable appendices. MWA will separately consider adoption of the entirety of the 2025 RUWMP and its WSCP.

Hesperia Water District
The Hesperia Water District will hold a public hearing as follows:

Date: May 19, 2026
Time: 6:30 PM
Location: City Council Chambers 9700 Seventh Ave., Hesperia CA, 92345 Copies of the draft 2025 RUWMP, including the Hesperia
Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at 9700 Seventh Ave., Hesperia CA, 92345 during
regular business hours and online at https://hesperia.legis- tar.com/Calendar.aspx Hi-Desert Water District
The Hi-Desert Water District will hold a public hearing as follows:

Date: June 3, 2026
Time: 5:00 PM
Location: 61750 Chollita Road Joshua Tree CA 92252
Copies of the draft 2025 RUWMP, including the Joshua Basin Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at 61750 Chollita Rd., Joshua Tree, CA during regular business hours and online at www.jbwd.com
Golden State Water Company – Barstow
Golden State Water Company – Barstow will hold a public hearing as follows:

Date: May 27, 2026
Time: 11:00 AM
Location: https://us06web.zoom.us/j/81445290033?pwd=
UijEvrIofbbXI4bRWJDhDO3PRaXi0J.1 Passcode: 757372
Copies of the draft 2025 RUWMP, including the Golden State Water Company – Barstow retailer-specific chapter and the Company’s WSCP and applicable appendices, will be avail- able for public review online at https://www.gswater.com/ Liberty Utilities – Apple Valley
Liberty Utilities – Apple Valley will hold a public hearing as follows:

Date: June 4, 2026
Time: 9:00 AM
Location: https://teams.microsoft.com/meet/284381397
435981?p=HKnYB1DhSKyacIZB6S Passcode: uc3Ee7km
Copies of the draft 2025 RUWMP, including the Liberty Utili- ties – Apple Valley retailer-specific chapter and Liberty Util- ities – Apple Valley WSCP and applicable appendices, will be available for public review online at https://libertyutilities. com/
San Bernardino County Service Area 64
The San Bernardino County Service Area 64 will hold a public hearing as follows:

Date: June 23, 2026
Time: 10:00 AM
Location: 385 North Arrowhead Avenue, First Floor, San
Bernardino, CA, 92415
Copies of the draft 2025 RUWMP, including the San Bernardi- no County Service Area 64 retailer-specific chapter and the CSA’s WSCP and applicable appendices, will be available for public review at 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 during regular business hours and online at https://sanbernardino.legistar.com/Calendar. aspx
San Bernardino County Service Area 70J
The San Bernardino County Service Area 70J will hold a
public hearing as follows:

Date: June 23, 2026
Time: 10:00 AM
Location: 385 North Arrowhead Avenue, First Floor, San
Bernardino, CA, 92415
Copies of the draft 2025 RUWMP, including the San Bernardi- no County Service Area 70J retailer-specific chapter and the CSA’s WSCP and applicable appendices, will be available for public review at 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 during regular business hours and online at https://sanbernardino.legistar.com/Calendar. aspx
Phelan Pinion Hills Community Services District
The Phelan Pinion Hills Community Services District will hold a public hearing as follows:

Date: June 10, 2026
Time: 5:00 PM
Location: 4176 Warbler Road, Phelan, CA 92371
Copies of the draft 2025 RUWMP, including the Phelan
Pinion Hills Community Services District retailer-specific chapter and the CSD’s WSCP and applicable appendices, will be available for public review at 4176 Warbler Road, Phelan, CA 92371 during regular business hours and online at www. pphcsd.org
City of Adelanto Water District
The City of Adelanto Water District will hold a public hearing as follows:

Date: June 10, 2026
Time: 11:00 AM
Location: Stadium - Conference Room 12000 Stadium Way
Adelanto, CA, 92301
Copies of the draft 2025 RUWMP, including the City of
Adelanto Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be avail- able for public review at 11600 Air Expressway Adelanto, CA 92301 during regular business hours and online at https:// adelantoca.gov/services/water_sewer/index.php
Mojave Water Agency
The Mojave Water Agency will hold a public hearing as
follows:

Date: June 11, 2026
Time: 9:30 AM
Location: MWA Board Room 13846 Conference Center Drive
Apple Valley, CA 92307
Copies of the draft 2025 RUWMP and the Agency’s WSCP and applicable appendices, will be available for public review at 13846 Conference Center Drive Apple Valley, CA 92307 during regular business hours and online at https://www. mojavewater.org/about-mwa/agency-calendar/meetings/
Victorville Water District
The Victorville Water District will hold a public hearing as follows:

NOTICE OF PUBLIC HEARINGS
ON THE 2025 MOJAVE REGIONAL URBAN WATER MANAGEMENT PLAN 367
2025 MOJAVE

REGIONAL URBAN WATER

MANAGEMENT PLAN
368
2025 Mojave RUWMP – Public Draft

TABLE OF CONTENTS
Executive Summary............................................................................................................................ES-1 Chapter 1.0 Introduction..................................................................................................................... 1-1

1.1.1 Background and Purpose.........................................................................................................................................................1-1

1.1.2 Basis for Plan Preparation .......................................................................................................................................................1-2

1.1.3 Coordination and Outreach ..................................................................................................................................................1-2

1.1.4 Statutory Requirements for Notice................................................................................................................................... 1-4

1.1.5 RUWMP Adoption.......................................................................................................................................................................... 1-4

1.1.6 Document Organization.......................................................................................................................................................... 1-4 Chapter 2.0 The Mojave Region.........................................................................................................2-1

2.1.1 Regional Overview........................................................................................................................................................................2-1

2.1.2 Water Suppliers of the Mojave Region.......................................................................................................................... 2-6

2.1.3 Mojave Region Groundwater Basins .............................................................................................................................. 2-9

2.1.4 Major Regional Infrastructure............................................................................................................................................2-15

2.1.5 Regional Climate.......................................................................................................................................................................2-20

2.1.6 Current and Projected Population.................................................................................................................................2-23

2.1.7 Land Use, Economy, and Demographics ..................................................................................................................2-28

2.1.8 Summary........................................................................................................................................................................................2-33 Chapter 3.0 Regional Water Supply Characterization.................................................................3-1

3.1.1 Mojave Region Water Supply Sources ............................................................................................................................3-1

3.1.2 Water Quality................................................................................................................................................................................3-10

3.1.3 Desalination Opportunities..................................................................................................................................................3-15

3.1.4 Delta Reliance ..............................................................................................................................................................................3-15

3.1.5 Climate Change.........................................................................................................................................................................3-16

3.1.6 Summary of Existing and Planned Water Supplies .............................................................................................3-16 Chapter 4.0 Water Use Characterization ....................................................................................... 4-1

4.1.1 Current Regional Water Use ................................................................................................................................................. 4-1

4.1.2 Forecasting Regional Water Use.......................................................................................................................................4-6

4.1.3 Summary of Future Regional Water Use .....................................................................................................................4-8 369
2025 Mojave RUWMP – Public Draft
Chapter 5.0 Regional Water Service Reliability ............................................................................ 5-1

5.1.1 Mojave Region Five-Year Drought Risk Assessment........................................................................................... 5-2

5.1.2 MWA Long-Term Service Reliability ................................................................................................................................ 5-3

5.1.3 Water Supply Reliability Summary.................................................................................................................................. 5-7 Chapter 6.0 Mojave Water Agency.................................................................................................. 6-1 Chapter 7.0 The City of Adelanto.......................................................................................................7-1 Chapter 8.0 County Service Area 64 Spring Valley Lake............................................................. 8-1 Chapter 9.0 County Service Area 70J Oak Hills............................................................................. 9-1 Chapter 10.0Golden State Water Company – Barstow System ................................................10-1 Chapter 11.0 Hesperia Water District................................................................................................11-1 Chapter 12.0 Hi-Desert Water District ............................................................................................. 12-1 Chapter 13.0Joshua Basin Water District.......................................................................................13-1 Chapter 14.0Liberty Utilities – Apple Valley...................................................................................14-1 Chapter 15.0Phelan Piñon Hills Community Services District ...................................................15-1 Chapter 16.0Victorville Water District ............................................................................................16-1 370
2025 Mojave RUWMP – Public Draft

LIST OF TABLES
Table 1-1: Public and Public Agency Coordination...........................................................................................................................1-3 Table 2-1: Urban Water Retail Water Suppliers within the Mojave Region ..................................................................... 2-8 Table 2-2: Groundwater Basins within the Mojave Region......................................................................................................2-10 Table 2-3: Historical Population................................................................................................................................................................2-24 Table 2-4: Comparison of Incorporated City Population Data...........................................................................................2-25 Table 2-5: Urban Water Supplier Population Projections – UCR Study and Adjusted UCR Study ................2-26 Table 2-6: Mojave Region Population Projections – UCR Study and Adjusted UCR Study................................2-26 Table 2-7: Adjusted UCR Study and SCAG Population Projections ...................................................................................2-27 Table 2-8: 2025 RUWMP Population Projections ............................................................................................................................2-28 Table 2-9: Known Land Use Plans in the Mojave Region..........................................................................................................2-30 Table 3-1: Projected Native Groundwater for each Subregion through 2050 (AFY)................................................ 3-6 Table 3-2: MWA’s Projected Imported Water Supplies (AFY)...................................................................................................3-7 Table 3-3: Summary of Return Flow for Subregion 1 and Subregion 2 through 2050 (AFY)............................... 3-8 Table 3-4: Recycled Water Supplies for Subregion 1 through 2050 (AFY)...................................................................... 3-9 Table 3-5: Average Existing TDS and Nitrate Concentrations by SNMP Subregion.................................................3-13 Table 3-6: Reduced Delta Reliance.........................................................................................................................................................3-16 Table 3-7: Projected Total Water Supply for the Mojave Region for the Next 5-Years (AFY)............................3-17 Table 3-8: Projected Total Water Supply for the Mojave Region Through 2050 (AFY).......................................... 3-17 Table 4-1: Regional Water Use 2021-2025 (AFY) .............................................................................................................................. 4-3 Table 4-2: Subregion 1 Water Use 2021-2025 (AFY).......................................................................................................................4-4 Table 4-3: Subregion 2 Water Use 2021-2025 ...................................................................................................................................4-5 Table 4-4: Subregion 3 Water Use 2021-2025...................................................................................................................................4-5 Table 4-5: Projected Subregion 1 Water Demand 2030-2050 (AFY)..................................................................................4-9 Table 4-6: Projected Subregion 2 Water Demand 2030-2050 (AFY) ................................................................................4-9 Table 4-7: Projected Subregion 3 Water Demand 2030-2050 (AFY).................................................................................4-9 Table 4-8: Projected Regional Water Demand 2030-2050 (AFY).......................................................................................4-10 Table 5-1: MWA Five Year Drought Risk Assessment (AFY)....................................................................................................... 5-3 Table 5-2: Normal and Single Dry Year Water Supply and Demand through 2050 (AFY) ..................................5-5 Table 5-3: Five Consecutive Dry Years Water Supply and Demand Through 2050 (AFY)...................................5-6 371
2025 Mojave RUWMP – Public Draft

LIST OF FIGURES
Figure 2-1: The Mojave Region ..................................................................................................................................................................... 2-3 Figure 2-2: Subareas and Management Areas within the Mojave Region.................................................................... 2-4 Figure 2-3: 2025 RUWMP Subregions....................................................................................................................................................... 2-6 Figure 2-4: Urban Water Retail Suppliers within the Mojave Region.................................................................................. 2-9 Figure 2-5: Groundwater Basins within the Mojave Region..................................................................................................... 2-11 Figure 2-6: Adjudicated Subareas and Defined Management Areas within the Mojave Region..................2-13 Figure 2-7: SWP Mojave Division Aqueduct Reach Sections...................................................................................................2-16 Figure 2-8: MWA Turnouts Along the East Branch......................................................................................................................... 2-17 Figure 2-9: R-Cubed Facilities ....................................................................................................................................................................2-19 Figure 2-10: Average Climate Conditions ........................................................................................................................................... 2-21 Figure 2-11: Annual Precipitation Variability (1996-2024) ......................................................................................................... 2-21 Figure 2-12: Historical Annual Temperature and Trends (years) .......................................................................................2-22 Figure 2-13: San Bernardino County Employment Data 2015-2025..................................................................................2-33 Figure 3-1: Floodplain and Other Regional Aquifers...................................................................................................................... 3-4 372
2025 Mojave RUWMP – Public Draft

APPENDICES
Appendix 1 – Notices ................................................................................................................................................................................A-1 Appendix 2 – Reduced Delta Reliance.........................................................................................................................................A-2 Appendix 3 - MWA Regional DWR Checklist..............................................................................................................................A-3 Appendix 4 – MWA WSCP....................................................................................................................................................................A-4 373
2025 Mojave RUWMP – Public Draft
This 2025 Regional Urban Water Management Plan (RUWMP) was prepared by Zanjero in conjunction with Mojave Water Agency.

This 2025 RUWMP was prepared under the direction of a California licensed civil engineer
The Victorville Water District Retail
Chapter contained within this RUWMP
was prepared by:

The Golden State Water Company -
Barstow System Retail Chapter
contained within this RUWMP was
prepared by:
374
Executive Summary Layperson’s Description
2025 Mojave RUWMP – Public Draft ES-1

EXECUTIVE SUMMARY
LAYPERSON’S DESCRIPTION
After the devasting drought in the late 1970s, the California Legislature declared California’s water supplies a limited resource, subject to ever-increasing demands, and that the longterm, reliable supply of water is essential to protect California’s businesses, communities, agricultural production, and environmental interests. The Legislature also recognized a need to strengthen local and regional drought planning and increase statewide resilience to drought and climate change. Thus, in 1983, the California Legislature created the Urban Water Management Planning Act (UWMPA).1 The UWMPA requires urban water suppliers serving over 3,000 customer connections or supplying at least 3,000 acre-feet of water annually to prepare and adopt an urban water management plan (UWMP) every five years,2 and demonstrate water supply reliability in a normal year, single dry year, and droughts lasting at least five years over a twenty-year planning horizon.3 The UWMPA also requires each urban water supplier to prepare a drought risk assessment and water shortage contingency plan. 4 In addition, each urban water supplier must prepare an annual water supply and demand assessment.5 The California Legislature emphasizes that aggregating these legal requirements at the urban water supplier management level will improve local, regional, and statewide water planning and water resilience.

At a practical level, the UWMP is the legal and technical water management foundation for urban water suppliers throughout California. A well-constructed UWMP provides elected officials, management, staff, customers, and the public with an understanding of past, current, and future water conditions. The UWMP integrates local and regional land use planning, water supply planning, infrastructure considerations, and demand management measures, while also addressing statewide challenges that may manifest through climate change, drought, and evolving regulations. Thoughtful urban water management planning provides an opportunity for water suppliers to integrate supplies and demands in a balanced and methodical planning platform that addresses short-term and long-term planning 1 California Water Code Section 10610 et seq. (Chapter 1 added by Stats. 1983, Ch. 1009, Sec. 1) and its subsequent amendments
2 California Water Code Section 10610 et seq.
3 California Water Code Section 10631-10635
4 California Water Code Section 10632
5 California Water Code Section 10632.1
375
Executive Summary Layperson’s Description
2025 Mojave RUWMP – Public Draft ES-2
conditions. In brief, the UWMP gathers, characterizes, and synthesizes water-related information from numerous sources into a plan with local, regional, and statewide practical utility.

ES-1 The Mojave Region
The 2025 Mojave Regional Urban Water Management Plan (2025 RUWMP or Plan) has been prepared by Mojave Water Agency (MWA) and the ten participating urban water suppliers within the Mojave Region. The Mojave Region is concurrent with MWA’s service area and encompasses approximately 4,900 square miles of eastern San Bernardino County. The Region includes a diverse mix of incorporated cities, unincorporated communities, rural domestic users, small water systems, industrial and recreational uses, agricultural uses, and urban retail water suppliers that depend primarily on local groundwater supplies supported by imported water management.

The 2025 RUWMP represents the first regional urban water management plan prepared for the Mojave Region. The regional planning approach allows MWA and the participating urban water suppliers to prepare a coordinated water management plan that evaluates shared regional water supplies, regional water demands, and long-term water service reliability using consistent assumptions and methodologies. This approach also reduces duplicative analyses, improves regional coordination, and provides a common technical foundation for local and regional decision-making.

The participating urban water suppliers include MWA, as the Region’s wholesale water supplier, and the urban water retail suppliers located within MWA’s service area. For adoption purposes, each participating urban water retail supplier will adopt Regional Chapters 1 through 5, MWA’s wholesale supplier chapter (Chapter 6), its own retail-specific chapter, its Water Shortage Contingency Plan (WSCP), and all applicable appendices. MWA will adopt the entirety of the 2025 RUWMP, including Regional Chapters 1 through 5, its wholesale supplier chapter, all participating retail supplier chapters, its WSCP, and all applicable appendices.

Chapters 1 through 5 provide the shared regional planning framework, including the regional description, regional water supply characterization, regional water use characterization, and regional water service reliability analysis. Chapter 6 describes MWA’s wholesale water supply, imported water management, managed groundwater storage, and other regional water management responsibilities. The retailer-specific chapters provide the additional information necessary to satisfy the UWMPA requirements for each participating urban water retail supplier.

The Mojave Region’s fundamental water management challenge is that urban, rural, industrial, agricultural, and other water demands have historically exceeded the natural replenishment capacity of local groundwater basins. Groundwater is the foundation of the Region’s water supply portfolio; however, that groundwater supply is actively managed through adjudications, stipulated agreements, imported State Water Project supplies, 376
Executive Summary Layperson’s Description
2025 Mojave RUWMP – Public Draft ES-3
recharge operations, return flows, recycled water, transfers, exchanges, and ongoing coordination among MWA, retail water suppliers, watermasters, land use agencies, and other regional partners. Together, these management actions support regional groundwater sustainability and long-term water service reliability.

For purposes of regional supply and demand evaluation, the 2025 RUWMP organizes the Mojave Region into three planning subregions. This subregional framework allows the Plan to recognize hydrologic, infrastructure, and demand differences across the Region while still evaluating overall regional reliability. The subregional framework also supports comparison of regional supplies and demands in a manner that is useful for both MWA’s wholesale planning responsibilities and the participating urban water suppliers’ retail planning responsibilities.

ES-2 Mojave Region Water Service Reliability
The 2025 RUWMP aggregates regional water supplies and demands through MWA’s role as the Region’s wholesale water supplier, State Water Project contractor, Watermaster for the Mojave Basin Area Adjudication, and administrator for the Warren Valley Basin Judgment.

Because the Mojave Region depends primarily on groundwater, regional reliability is not evaluated solely by comparing annual imported water deliveries to annual demands.

Instead, reliability is evaluated based on the coordinated management of groundwater, imported water, return flows, recycled water, stored water assets, transfers, exchanges, and the legal and institutional frameworks that govern water use across the Region.

The 2025 RUWMP extends the regional planning horizon through 2050. This planning horizon allows MWA and the participating urban water suppliers to evaluate long-term population growth, land use changes, water demand trends, imported water reliability, groundwater management conditions, recycled water opportunities, and infrastructure needs. These considerations help improve regional coordination and provide a common planning framework for local and regional water management decisions.

As described in Chapter 3 – Regional Water Supply Characterization, the Mojave Region’s water supply portfolio includes native groundwater, imported State Water Project supplies, return flows, recycled water, and other managed water supplies. These supplies are not all used in the same manner or at the same time. Native groundwater and return flows help support recurring local supply conditions; imported water is used by MWA to support recharge, replacement water obligations, and regional groundwater management; recycled water helps offset potable demands at the retail water supplier level where available; and stored water assets provide an important management tool for addressing hydrologic variability, imported water fluctuations, and dry-year conditions.

Chapter 4 – Water Use Characterization, characterizes current and projected regional water demands, including demands associated with participating urban water retail suppliers and other regional water users. These demands are organized by subregion to support regional 377
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supply and demand comparisons while recognizing that water use, groundwater conditions, infrastructure, and management needs vary across the Mojave Region. The regional demand forecast provides a common planning basis for evaluating long-term reliability and for coordinating wholesale and retail water management actions.

Chapter 5 – Regional Water Service Reliability, evaluates regional water service reliability under normal year, single dry year, and five consecutive dry year conditions through 2050, as well as the five-year Drought Risk Assessment for 2026 through 2030. The analysis demonstrates that the Mojave Region has sufficient managed water supplies to meet projected regional demands under the planning scenarios evaluated in this RUWMP. The analysis also recognizes that reliability depends on continued regional management, including MWA’s importation and recharge of supplemental water supplies, implementation of adjudication requirements, use of stored water assets when needed, local retail supplier management, recycled water development where feasible, and continued demand management.

The Region’s water assets are based understood as a regional reliability and management tool rather than a recurring annual supply that should be added directly to all other annual supplies. MWA stores water in wet and normal years to help manage dry-year risks, imported water variability, and groundwater basin conditions. These stored supplies provide operational flexibility and support long-term resilience, but their use is guided by hydrologic conditions, infrastructure capacity, basin management objectives, adjudication requirements, and regional water management priorities.

Each participating urban water retail supplier also evaluates water service reliability within its own chapter. Those chapters address local supply portfolios, demands, infrastructure, conservation measures, and WSCPs. Together, the regional analysis and retailer-specific analyses demonstrate that the 2025 RUWMP provides a coordinated and locally implementable framework for maintaining reliable water service throughout the Mojave Region.

In summary, the Mojave Region’s coordinated management of groundwater, imported water, return flows, recycled water, transfers, exchanges, and stored water assets provides a reliable water supply portfolio to meet current and projected regional demands through 2050. The 2025 RUWMP demonstrates that the Region has reliable water supplies under normal, single dry, and five consecutive dry year conditions, while also providing the foundation for annual water supply and demand assessments and implementation of retailer-specific WSCPs. 378
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Chapter 1.0 INTRODUCTION
The 2025 Mojave Regional Urban Water Management Plan (2025 RUWMP, RUWMP, or Plan) establishes a long-term, coordinated framework for regional water resources planning and management through the year 2050 for the Mojave Region. The 2025 RUWMP applies to Mojave Water Agency (MWA or Agency) as the regional wholesale water supplier and to participating urban water suppliers within MWA’s service area. This Plan represents the first RUWMP prepared for the Mojave Region and reflects a shared commitment to integrated, collaborative, and forward-looking water management.

The RUWMP provides a consistent assessment of long-term water supply reliability, supports groundwater sustainability, and addresses regional vulnerability to drought, climate change, and population growth. The RUWMP is intended to inform elected officials, water supplier staff, water users, interested community parties, and the State of California regarding current conditions, projected demands, and strategies to ensure reliable and sustainable water supplies.

Participating urban water suppliers include:
• City of Adelanto
• County Service Area 64
• County Service Area 70J
• Hesperia Water District
• Hi-Desert Water District
• Golden State Water Company –
Barstow System
• Joshua Basin Water District
• Liberty Utilities – Apple Valley Water
Company
• Mojave Water Agency (Wholesale)
• Phelan Piñon Hills Community
Services District
• Victorville Water District
While this RUWMP provides regionally consistent planning assumptions and analyses, each urban water supplier will separately prepare and adopt a Water Shortage Contingency Plan (WSCP) customized for its specific service area. The RUWMP and associated WSCPs will be adopted in accordance with statutory deadlines.

1.1.1 Background and Purpose
The California Urban Water Management Planning Act (UWMPA) requires urban water suppliers serving at least 3,000 connections or delivering more than 3,000 acre-feet of water 379
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annually to prepare an Urban Water Management Plan (UWMP) every five years. The UWMPA authorizes multiple urban water suppliers that share common water supplies to prepare a RUWMP in lieu of individual plans.

Recognizing the benefits of regional coordination, MWA and its urban water retail suppliers jointly elected to prepare this RUWMP. Compared with developing separate agency-specific UWMPs, a regional approach promotes consistent technical assumptions, reduces duplicative effort, improves cost efficiency, enhances data accuracy, and strengthens the region’s ability to pursue state and federal funding opportunities.

1.1.2 Basis for Plan Preparation
The purpose of the 2025 RUWMP is to provide a coordinated evaluation of regional water supplies, demands, and management strategies shared among participating agencies. By developing a single regional planning document, participating agencies leverage collective data resources, technical expertise, and institutional knowledge to support consistent planning and informed long-term decision-making.

This 2025 RUWMP fulfills the reporting requirements established by the California Department of Water Resources (DWR) to implement the UWMPA and aligns with statewide water management objectives. The Plan satisfies statutory requirements for MWA as a wholesale urban water supplier and for each participating retail urban water supplier.

1.1.3 Coordination and Outreach
Development of the 2025 RUWMP included coordination with local governments, neighboring water agencies, and relevant regulatory entities, as required by the UWMPA. Coordination efforts were undertaken to ensure consistency with applicable city and county General Plans, Water Master Plans, groundwater adjudications and stipulations, and other related planning documents.

In accordance with California Water Code Section (CWC) 10621(b), MWA and the participating urban water suppliers conducted joint public outreach and provided required public notices prior to adoption of the RUWMP by each individual urban water supplier. A summary of coordination and public outreach activities is provided in Table 1-1. 380
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TABLE 1-1: PUBLIC AND PUBLIC AGENCY COORDINATION
Coordinating Agencies
Coordinate
Regarding
Demands
Sent Copy
of Draft
RUWMP
Sent
60-Day
Notice
Notice of
Public
Hearing
Cities, Counties, Customers, and Relevant Parties
Liberty Utilities (Apple Valley Water Company) X X X X
Bighorn-Desert View Water Agency X X X
City of Adelanto X X X X
County Service Area 64 X X X X
County Service Area 70J X X X X
Golden State Water Company - Barstow System X X X X
Helendale CSD X X X
Hesperia Water District X X X X
Hi-Desert Water District X X X X
Joshua Basin Water District X X X X
Mojave Water Agency X X X X
Phelan Piñon Hills CSD X X X X
Victorville Water District X X X X
San Bernardino County Planning Department X X
California Department of Water Resources X X
Local Agency Formation Commission (LAFCO) for San Bernardino County
X X
General Public X

1.1.3.1 Water Supplier Information Exchange
CWC Section 10631 requires wholesale and urban water suppliers to provide each other with information regarding water supply and demand. Since both MWA, as a wholesale supplier that receives water from the California State Water Project (SWP) on behalf of the Mojave Region, and each of the urban water suppliers are already coordinating on this RUWMP, information exchange was happening throughout the RUWMP development, and any separate noticing was unnecessary.
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1.1.4 Statutory Requirements for Notice
In accordance with the UWMPA, notification of the RUWMP update was provided to cities and counties within the RUWMP Planning Area at least 60 days prior to the public hearing of the RUWMP as required by CWC Section 10621(b). Electronic copies of the final RUWMP will be provided to the County of San Bernardino no later than 30 days after its submission to DWR.

1.1.5 RUWMP Adoption
Each participating agency has reviewed, approved, and will implement the portions of this RUWMP that are specific and applicable to their service area. While the RUWMP was developed collaboratively to ensure consistency and coordination across the Mojave Region, not all elements of the RUWMP apply equally to every agency. The RUWMP is therefore organized in a modular format, where Chapters 1 through 5 are universal, and Chapters 6 through 16 are unique to each participating agency. This approach allows each agency to adopt Chapters 1 through 5 collectively with their agency-specific chapter and relevant WSCP. As such, the specific timing of adoption for each supplier is referenced within their unique chapter of the RUWMP.

Any future amendments or updates made by individual agencies to their respective chapter will not alter or affect the adopted portions of the RUWMP for other participating agencies.

This structure preserves local autonomy while maintaining the benefits of regional coordination, ensuring that all agencies continue to contribute to a unified framework for sustainable water management within the Mojave Region and the MWA service area.

1.1.6 Document Organization
This RUWMP is organized to reflect the collaborative efforts of all participating agencies, while still allowing each agency to meet its respective statutory reporting requirements. As such, the 2025 RUWMP is organized as follows:
• Chapter 1 – Introduction
• Chapter 2 – The Mojave Region
• Chapter 3 – Regional Water Supply Characterization
• Chapter 4 –Regional Water Use
• Chapter 5 – Regional Water Service Reliability
• Chapter 6 – Mojave Water Agency (Wholesale Water Supplier) • Chapter 7 – City of Adelanto (Urban Water Supplier)
• Chapter 8 – County Service Area 64 (Urban Water Supplier) • Chapter 9 – County Service Area 70J (Urban Water Supplier) 382
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• Chapter 10 – Golden State Water Company – Barstow (Urban Water Supplier) • Chapter 11 – Hesperia Water District (Urban Water Supplier) • Chapter 12 – Hi-Desert Water District (Urban Water Supplier) • Chapter 13 – Joshua Basin Water District (Urban Water Supplier) • Chapter 14 – Liberty Utilities – Apple Valley Water Company (Urban Water Supplier) • Chapter 15 – Phelan Piñon Hills Community Service District (Urban Water Supplier) • Chapter 16 – Victorville Water District (Urban Water Supplier) Note to DWR:

The MWA and the urban water suppliers within its service area have written this RUWMP primarily as a water resource planning tool to effectively manage water supply, reliability, and demand. This RUWMP also satisfies all the requirements of the UWMPA for MWA (as a wholesale urban water supplier) and for each participating urban water supplier.

The body of the document provides narratives, analysis, and data that DWR requests in its 2025 UWMP Guidebook, including any changes to the CWC since 2020. Efforts have also been made to include enhancements to this document wherever possible as recommended in the 2025 UWMP Guidebook.

To facilitate review by DWR for compliance with the UWMPA, data from the body of the document has been transferred into required DWR submittal tables consistent with the organization of the tables in Appendix E of the 2025 UWMP Guidebook. These tables are separately uploaded to DWR’s web portal for each of the participating urban water suppliers, along with this RUWMP. This RUWMP has been reviewed for adequacy according to the UWMP Checklist as contained in Appendix F of the 2025 UWMP Guidebook. 383
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Chapter 2.0 THE MOJAVE REGION
This chapter provides an overview of the Mojave Region (Region or RUWMP Planning Area) including its population characteristics, land use patterns, and climate conditions. It also introduces the various local entities and water purveyors that play key roles in managing and delivering water resources throughout the Region. As a foundational reason for preparation of this RUWMP, the Mojave Region is also concurrent with the MWA service boundary, which also fully encompasses all participating urban water suppliers that must also comply with the UWMPA. The Mojave Region, as a result, allows this RUWMP to capture the entirety of MWA’s service area, as well as the service areas of each of the urban water suppliers that sit within MWA.

2.1.1 Regional Overview
The Mojave Region encompasses approximately 4,900 square miles of eastern San Bernardino County (Figure 2-1), corresponding to the MWA’s service area. MWA serves as the Region’s wholesale water supplier and as Watermaster for the Mojave Basin Area (MBA) adjudication. Located within the Mojave Desert of southeastern California, the Region includes several large, incorporated communities that collectively drive substantial and growing water demands despite extremely arid conditions.

The intermittent Mojave River is the Region’s principal hydrologic feature. Its episodic flows provide the primary source of natural recharge to underlying groundwater basins and serve as a critical conveyance for imported SWP supplies used for managed groundwater recharge. Regional water management is shaped by a persistent structural water deficit, in which current primarily urban-driven demands exceed the natural replenishment capacity of local aquifers. Imported water is therefore essential to mitigating groundwater overdraft and supporting long-term regional sustainability.

Water management is organized across multiple geographic and administrative scales. At the regional level, MWA is responsible for managing and importing supplemental water supplies and coordinating their integration with local groundwater resources in cooperation with state, regional, and local partners. From a hydrogeographic perspective, the Region overlies all or portions of 36 groundwater basins and subbasins. For planning and management purposes, MWA groups these basins into eight subareas that cover the entire Region. Although the subareas are partially defined by faults and other geologic features, they generally remain hydrologically interconnected. Five subareas—Este, Oeste, Alto 384
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(including the Alto Transition Zone), Centro, and Baja—are within the MBA adjudication and are named for their relative position along the Mojave River. The remaining three subareas lie outside the adjudicated basin and were part of MWA’s original service area or incorporated through subsequent adjudication actions. All eight subareas are managed in a coordinated manner by MWA, the MBA Watermaster and the Warren Valley Basin Watermaster, and the numerous urban water suppliers (Figure 2-2).

At the local level, urban water retail suppliers—particularly those serving the cities of Victorville, Hesperia, Adelanto, and Barstow along the Interstate 15 corridor—are the primary contributors to regional growth and future water demand. Expansion of these service areas directly influences regional demand conditions and the management strategies applied within individual subareas, with the most pronounced effects occurring in incorporated cities.

Groundwater provides the foundation of the Region’s water supply portfolio. Supplies consist of a managed combination of native groundwater and imported water, overseen by MWA on behalf of its constituent retail agencies, used to meet all demands within the Region.

Recharge of native groundwater occurs through multiple mechanisms, including infiltration from the Mojave River and ephemeral streams, percolating rainwater, stormwater runoff, sublateral groundwater flow from surrounding mountains, treated wastewater and return flows, septic and irrigation seepage, and managed recharge of imported SWP supplies. As the SWP contractor for the Mojave Region, MWA manages the delivery and recharge of imported water using both the Mojave River and recharge sites located throughout its service area.

Effective water management in the Mojave Region relies on extensive coordination among MWA, retail water agencies, mutual water companies, adjudication watermasters, tribal entities, rural and self-supplied users, and land use and regulatory agencies. This collaboration supports coordinated infrastructure planning, groundwater monitoring, imported water operations, and drought response within a broader framework of regional and statewide water planning.
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FIGURE 2-1: THE MOJAVE REGION
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FIGURE 2-2: SUBAREAS AND MANAGEMENT AREAS WITHIN THE MOJAVE REGION 387
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For the purposes of this RUWMP and evaluation of water supply reliability, the eight subareas are combined into the following three Subregions of the Mojave Region (Figure 2-3). • Subregion 1 – Includes the subareas of Oeste, Alto (and Alto Transition), and Este: This subregion includes seven of the 10 participating RUWMP urban water suppliers (City of Adelanto, County Service Area 64, County Service Area 70J, Hesperia Water District, Liberty Utilities – Apple Valley, Phelan-Piñon Hills Community Service District, and Victorville Water District), as well as other demands reliant on MWA including other small urban water suppliers, Helendale Community Services District, rural pumpers, agriculture, and industry.
• Subregion 2 – Includes the subareas of Centro, Baja, Cuddeback Lake, and Superior Lake: This subregion includes one of the participating RUWMP urban water suppliers (Golden State Water Company-Barstow), as well as other demands reliant on MWA including other small urban water suppliers, rural pumpers, agriculture, and industry. • Subregion 3 – Includes the subarea of Morongo: This subregion includes two of the 10 RUWMP urban water suppliers (Joshua Basin Water District and Hi-Desert Water District), as well as other demands reliant on MWA including other small urban water suppliers, Bighorn-Desert View Water Agency, rural pumpers, agriculture, and industry.

These Subregions are used to summarize demand and supply conditions in areas with generally similar groundwater conditions and MWA imported water opportunities. 388
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FIGURE 2-3: 2025 RUWMP SUBREGIONS

2.1.2 Water Suppliers of the Mojave Region
The Mojave Region is geographically diverse but generally characterized as the High Desert.

Most of the region sits between 2,000 and 5,000 feet in elevation and extends across incorporated cities, unincorporated communities, tribal lands, and large expanses of undeveloped open space. Within this Region there are several water suppliers that must comply with the UWMPA, with MWA having responsibilities as a wholesale water supplier, and several others having responsibility as urban water retail suppliers. 389
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2.1.2.1 Mojave Water Agency
MWA serves as the wholesale water supplier for the Mojave Region and manages water supply reliability across its approximately 4,900‑square‑mile service area. The Agency’s core responsibility is to address the Region’s structural water management challenges, including limited local runoff and chronic groundwater overdraft within underlying basins and subbasins.

To support long-term sustainability for its retail agency partners and other customers, MWA manages the importation of SWP supplies from the California Aqueduct. In addition, MWA serves as the court-appointed Watermaster for the MBA Adjudication Judgment (MBA Judgment) (see Chapter 3 – Water Supply Characterization), where it regulates groundwater production and coordinates water management activities across the adjudicated subareas.

Although MWA does not provide retail water service, it fulfills a central regional function by integrating imported supplies with local groundwater management to enhance supply reliability, facilitate groundwater recharge, and improve drought resilience. This role requires ongoing coordination with retail water purveyors, adjudication watermasters, and other regional stakeholders to align imported water operations with groundwater sustainability objectives and broader regional planning efforts.

2.1.2.2 Urban Water Retail Suppliers
There are a variety of small-to-large state-permitted Public Water Systems, also referred to as urban water suppliers, located in the Mojave Region. As noted above, MWA does not sell water directly to these retailers or to any consumers; rather, it supplies water to areas of the Region used to recharge local aquifers for specific retailers as needed to satisfy the MBA Judgment’s replenishment requirements, as stipulated by the MBA Watermaster, as requested to meet needs in other adjudicated areas, and as needed to maintain overall groundwater basin health or requested to address local circumstances or retail requests. Of the twelve (12) large urban water suppliers within the Region, ten (10) are required to complete an UWMP pursuant to the UWMPA detailed in CWC Section 10610 et al. The 12 large urban water suppliers are shown in Figure 2-4.

For the ten large suppliers required to prepare a UWMP, they collectively opted to pursue a coordinated RUWMP with MWA in lieu of ten individual UWMPs, hence this 2025 Regional UWMP document. Table 2-1 lists the 10 suppliers that participated in this RUWMP, approximate service areas, and estimated total number of connections. Both Bighorn-Desert View Water Agency and Helendale Community Services District are incorporated into MWA’s wholesale demand forecast presented in Chapter 6 - Mojave Water Agency, as they both have not reached the UWMPA compliance threshold of 3,000+ service connections and/or do not supply more than 3,000 acre-feet of water per year, but have significant demands and are active coordinators within the Region.
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TABLE 2-1:URBAN WATER RETAIL SUPPLIERS WITHIN THE MOJAVE REGION Urban Water Retail Supplier Service Area
(sq. miles)
Approximate
Connections
City of Adelanto 53 8,300
Liberty Utilities - Apple Valley Water Company 51 21,000 County Service Area 64 4 4,000
County Service Area 70J 28 3,400
Golden State Water Company - Barstow System 33 9,000
Hesperia Water District 78 27,600
Hi-Desert Water District 57 11,000
Joshua Basin Water District 97 4,900
Phelan Piñon Hills Community Service District 118 7,200 Victorville Water District 85 38,000
Bighorn-Desert View Water Agency 52 < 2,000
Helendale Community Services District 116 < 3,000
Several additional urban water suppliers dependent on MWA’s supplies and management are not specifically discussed within unique chapters of this RUWMP as their size does not yet require completion of a UWMP. However, these smaller suppliers, as well as numerous other water users dependent on groundwater throughout the Region such as agriculture, industry, and rural domestic pumpers, are reflected in MWA’s Wholesale chapter (Chapter 6 - Mojave Water Agency) and are incorporated into the Region’s overall water demand characterization.
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FIGURE 2-4:URBAN WATER RETAIL SUPPLIERS WITHIN THE MOJAVE REGION

2.1.3 Mojave Region Groundwater Basins
The Mojave Region overlies all or a portion of 36 groundwater basins and subbasins as defined by DWR Bulletin 118. Collectively, these basins and subbasins are broadly grouped into two larger hydrogeologically distinct areas – the South Lahontan Hydrologic Region and the Colorado River Hydrologic Region. Groundwater basins along the Mojave River and adjacent areas are referred to as the Mojave River Groundwater Basin. Remaining basins and subbasins in the southeastern Mojave Region are generally referred to as the Morongo Basin/Johnson Valley Area or “Morongo Area,” with the exception of the Lucerne Valley. The Lucerne Valley Subbasin is divided along the Helendale Fault with the southwest portion in the Mojave River Groundwater Basin and the northeast portion in the Morongo Area. Surface 392
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water drainage of Lucerne Valley is in the Colorado River Hydrologic Region but is not included in the Morongo Basin Area, isolating this area due to the hydrogeologic conditions.

Of the two main areas, the Mojave River Groundwater Basin is the largest. The 36 groundwater basins and subbasins are listed in Table 2-2 and grouped by the South Lahontan (Region 6) and Colorado River (Region 7) Hydrologic Regions. The Mojave Region also overlaps a small portion of a DWR basin in the South Coast Hydrologic Region (Region 8) as shown by the last subbasin listed in Table 2-2 – the Upper Santa Ana Valley. These basins are also shown in Figure 2-5.

TABLE 2-2: GROUNDWATER BASINS WITHIN THE MOJAVE REGION
DWR Basin Groundwater Basin Name DWR Basin Groundwater Basin Name South Lahontan Hydrologic Region Colorado River Hydrologic Region 6-35 Cronise Valley 7-10 Twentynine Palms Valley
6-36 Langford Valley 7-11 Copper Mountain Valley
6-37 Coyote Lake Valley 7-12 Warren Valley
6-38 Caves Canyon Valley 7-13 Deadman Valley
6-40 Lower Mojave River Valley 7-13 Deadman Valley
6-41 Middle Mojave River Valley 7-15 Bessemer Valley
6-42 Upper Mojave River Valley 7-16 Ames Valley
6-43 El Mirage Valley 7-17 Means Valley
6-44 Antelope Valley 7-18 Johnson Valley
6-46 Fremont Valley 7-18 Johnson Valley
6-47 Harper Valley 7-19 Lucerne Valley
6-48 Goldstone Valley 7-20 Morongo Valley
6-49 Superior Valley 7-50 Iron Ridge Area
6-50 Cuddeback Valley 7-51 Lost Horse Valley
6-51 Pilot Knob Valley 7-62 Joshua Tree
6-52 Searles Valley 8-2 Upper Santa Ana Valley
6-53 Salt Wells Valley
6-54 Indian Wells Valley
6-77 Grass Valley
6-89 Kane Wash Area
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FIGURE 2-5: GROUNDWATER BASINS WITHIN THE MOJAVE REGION 394
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Challenges in managing overdrafted groundwater resources along with the high cost of importing water drove the first adjudication efforts in the Region in the 1960s. In 1965, Morongo Basin was annexed into MWA’s service area adding 35.5 square miles to MWA’s boundary.

The Morongo Basin was a sixth but separate area that added management and delivery obligations beyond the five other distinct hydrological subareas within the Mojave Basin Area:

Este (East Basin), Oeste (West Basin), Alto (Upper Basin), Centro (Middle Basin) and Baja (Lower Basin).

2.1.3.1 Mojave River Basin
The Mojave River Basin (Mojave Basin Area or MBA) is the principal water management area of the Region. For management purposes, the MBA is separated into five distinct hydrologic divisions defined in previous studies (DWR, 1967), evolving over time based on a combination of hydrologic, geologic, engineering, and political considerations (Figure 2-6).

A second effort at adjudication within the MBA starting in 1990 proved more successful than attempts in the 1960s. The effort resulted in full adjudication of the MBA in 2002.6 It began when the City of Barstow and the Southern California Water Company filed a complaint against upstream (and up-basin) water users claiming that lowering groundwater levels and water availability due to withdrawals reduced the amount of water available to downstream users. A year later, MWA filed a cross-complaint declaring that native waterflow of the Mojave River and basin area groundwater was not sufficient to meet current and future demands.

The cross-complaint asked the court to determine surface and groundwater rights for the Mojave Basin Area. Negotiations over the next two years produced a Stipulated Judgment in January 1996 that formed a class of producers which used 10 acre-feet or less per year that were dismissed from litigation and offered an equitable solution for the remaining water producers that use over 10 acre-feet per year (aka Minimal Producers). The Riverside Superior Court appointed MWA as Watermaster for the area as part of the MBA Judgment. Appeals by non-stipulated parties continued over the next several years with the California Supreme Court finally ruling on the case in August 2000. Most of the appealing parties have stipulated to the MBA Judgment since the 1996 ruling.

The MBA Judgment helps maintain proper water balances between the Mojave Basin Area’s five distinct, but interrelated, subareas (Este, Oeste, Alto, Centro, Baja). The Alto Transition Zone was also defined as a sub-management unit to better understand the water flow from Alto to Centro. Some subareas were also recognized to historically receive natural water flow from upstream subareas; to maintain that relationship, annual obligations are set according to average annual natural flow baselines defined in the MBA Judgment as Base Annual Production (BAP). The MBA Judgment established a Free Production Allowance (FPA) allocation to Producers based on each Producer’s percentage share of the BAP which is set 6 The MBA Judgment can be accessed at Mojave Water Agency’s website:
https://www.mojavewater.org/basin-management/watermaster/reports/ 395
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each year by the MBA Watermaster. FPA is reduced over time until it comes within 5% of the Production Safe Yield (PSY) defined by the MBA Judgment. All water produced in excess of any Producer’s share of the FPA must be replaced by the Producer, either by payment to the Watermaster of funds sufficient to purchase Replacement Water, or by transfer of unused FPA from another Producer. The court can review and adjust the FPA for each Subarea on an annual basis as appropriate. The dynamics of the FPA and resulting forecasts of available native groundwater for the general subareas are discussed in more detail in Chapter 3 - Water Supply Characterization.

FIGURE 2-6: ADJUDICATED SUBAREAS AND DEFINED MANAGEMENT AREAS WITHIN THE MOJAVE REGION

2.1.3.2 Morongo Area
The Morongo Area includes 15 groundwater basins and subbasins that cover portions of the Morongo Area as defined in this RUWMP and shown in Figure 2-5. Several of these basins lie mostly outside of the Mojave Region, have low populations, and are essentially undeveloped 396
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with respect to groundwater. The remaining basins have been grouped into six within the Morongo Area, with two of primary importance: the Warren Valley Basin and Ames Valley Basin.

2.1.3.3 Warren Valley Basin
The Warren Valley Basin covers an area of approximately 17,200 acres and consists of waterbearing sediments beneath the Town of Yucca Valley and surrounding area. The Warren Valley Basin (Figure 2-6) is geologically defined by the Pinto Mountain Fault to the north; a bedrock outcrop of the Little San Bernardino Mountains to the south; a bedrock constriction called the ‘Yucca Barrier’ to the east; and by a bedrock constriction and topographic divide to the west. Natural recharge to the Warren Valley Basin includes direct percolation of precipitation and percolation of ephemeral streamflow from Water Canyon and Covington Canyon.

After extractions began exceeding supplies in the 1950s, the area was adjudicated in 1977 in a decision known as the Warren Valley Judgment. Hi-Desert Water District (HDWD) was appointed Watermaster in the Judgment (the “Warren Valley Watermaster”) and was ordered to help develop solutions to halting overdraft. A comprehensive approach was developed by the Warren Valley Watermaster Board which included adopting a Basin Management Plan that called for SWP water delivery from MWA through the Morongo Basin Pipeline (MBP) to address demand and replenish overdraft. Native groundwater supplies associated with the Warren Valley Judgment are described in more detail in Chapter 3 - Water Supply Characterization.

2.1.3.4 Ames Valley Basin
In 2014 the Ames/Reche Groundwater Storage and Recovery Program and Management Agreement replaced and superseded the original adjudication called Ames Valley Basin Water Agreement between HDWD and Bighorn-Desert View Water Agency (BDVWA) established in 1991. It was created for the construction and operation of the HDWD Mainstream Well located in the Ames Valley Basin (Figure 2-6). The 2014 Agreement was established by BDVWA, HDWD, and County of San Bernardino, with administrative support provided by MWA, and the Stipulation and Amended and Restated Judgment (Ames/Reche Judgment) was finalized by the Superior Court of California, County of Riverside in September 2014. The Ames/Reche Management Area includes 95 square miles encompassing the communities of Flamingo Heights, Landers, Pioneertown, and Yucca Mesa. Native groundwater supplies associated with the Ames/Reche Judgment are described in more detail in Chapter 3 - Water Supply Characterization.
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2.1.4 Major Regional Infrastructure
This sub-chapter focuses specifically on MWA’s water delivery infrastructure. Individual infrastructure assets, such as distribution pipelines, well locations or other attributes, associated with each urban water supplier are discussed in their corresponding chapter.

2.1.4.1 State Water Project
The SWP or California Aqueduct is the largest state-built, multi-purpose water project in the country. It was authorized by the California State Legislature in 1959, with the construction of most facilities completed by 1973. Today, the SWP includes 28 dams and reservoirs, 26 pumping and generating plants, and approximately 660 miles of aqueducts.

The primary water source for the SWP is the Feather River, a tributary of the Sacramento River.

The water flowing into the Feather River is captured by the SWP in Oroville Dam and Reservoir.

Storage released from Oroville Dam flows down natural river channels to the SacramentoSan Joaquin River Delta (Delta). While some SWP supplies are pumped from the northern Delta into the North Bay Aqueduct or diverted by SWP contractors upstream, the vast majority of SWP supplies are pumped from the southern Delta into the 444-mile-long California Aqueduct. The California Aqueduct conveys water along the west side of the San Joaquin Valley to the Edmonston Pumping Plant, where water is pumped over the Tehachapi Mountains. From there the California Aqueduct divides into the East and West Branches. MWA takes its SWP deliveries from the East Branch, which was completed in 2003. MWA delivers its SWP supplies to recharge local groundwater basins through transmission pipelines, recharge facilities, and direct releases from Silverwood Lake – a SWP regulating reservoir. Figure 2-7 depicts the SWP facilities that deliver water to MWA and details the sections of the Mojave Division Reaches of the California Aqueduct.

The initial SWP storage and conveyance facilities were designed to meet contractors’ water demands with the construction of additional storage facilities planned as demand increased.

However, few additional SWP storage facilities have been constructed since the early 1970’s and a portion of the original conveyance design was never completed. SWP conveyance facilities were generally designed and have been constructed to deliver Table A amounts to all contractors. The maximum Table A Annual Amount of all SWP Contractors totals approximately 4.133 million acre-feet but full Table A Annual Amount deliveries rarely occur.

Details regarding MWA’s characterization of SWP reliability is discussed in MWA’s wholesale Chapter 6 – Mojave Water Agency.

MWA diverts its SWP water from the East Branch of the California Aqueduct, which includes six turnout locations utilized by MWA (identified west to east): Sheep Creek Turnout, White Road Turnout, Highway 395 Turnout, Antelope Siphon Turnout, Unnamed Wash, and Cedar Springs Dam (Silverwood Lake). These turnouts are used to deliver water to recharge facilities located 398
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throughout the MWA service area. Figure 2-8 below depicts the MWA water turnout and delivery facilities.

FIGURE 2-7: SWP MOJAVE DIVISION AQUEDUCT REACH SECTIONS 399
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FIGURE 2-8: MWA TURNOUTS ALONG THE EAST BRANCH
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2.1.4.2 Delivery System
MWA relies on the SWP contracted supplies to supplement local groundwater supplies throughout the Region using the Mojave River and two primary pipelines. The Mojave River Pipeline (MRP) is approximately 76 miles long, extending from the California Aqueduct in the Phelan area to four groundwater recharge basins along the Mojave River. These recharge basins are located in Hodge, Lenwood, Daggett/Yermo, and Newberry Springs. The MRP delivers up to 45,000 acre-feet of water per year to the Region. An additional pilot recharge basin is also currently under construction: the West Victorville Recharge Basin, located at the turnout of the MRP and adjacent to the California Aqueduct.

The second major pipeline linking the SWP to the subareas in the Region is the Morongo Basin Pipeline, which currently delivers water to groundwater recharge sites in Landers, Yucca Valley, and Joshua Tree to help address supplemental water needs for the Ames/Reche Judgment and the Warren Valley Judgment. The pipeline also allows MWA to deliver imported water into the Mojave River at the Deep Creek and Rock Springs discharge locations that serve the needs of the MBA Judgment. These two facilities are in areas of the River with high percolation rates, allowing water to recharge the aquifer directly upstream of the area with the highest groundwater pumping demand in MWA’s service area (the Alto subarea).

The facility includes a pipeline which extends south along the river from the MBP, a flow control facility and outlet. It can recharge a maximum of approximately 40,000 acre-feet per year.

The Amethyst Basin Facility, completed in 2019, delivers SWP water to recharge the Oro Grande Wash in Victorville just east of Sycamore Street and Amethyst Road in Victorville. It provides flood control and allows recharge through a series of dikes and recharge ponds.

Water from the SWP is delivered to the recharge ponds through a pipeline that connects to the California Aqueduct at the Highway 395 turnout. Recharge capacity is about 8,000 acrefeet per year.

The Ames/Reche Recharge Facility delivers water from the SWP directly to the Pipes Wash in Landers, located north of Yucca Valley. The Ames/Reche facility consists of a pipeline extending west from the MBP at Winters Road to an outlet in Pipes Wash. Construction of the pipeline, flow control facility, and outlet was completed in 2014. The turnout is planned to flow up to a maximum capacity of five cubic feet per second, recharging a maximum of approximately 1,500 acre-feet per year.

Silverwood Lake is a reservoir owned and operated by the State of California and DWR. At the California Aqueduct terminus in Hesperia, water is siphoned into the lake where it is stored for use in San Bernardino and Inland Empire areas. MWA takes deliveries of SWP from the lake via the Cedar Springs Dam which releases into the Mojave River.

Reflecting a more recent addition to the Region’s infrastructure, MWA constructed and operates the Regional Recharge and Recover Project (R-Cubed). This conjunctive use project 401
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stores SWP deliveries in recharge sites in the Floodplain Aquifer along the Mojave River near Hesperia and southern Apple Valley (Figure 2-9). When needed, MWA-owned production wells on both sides of the Mojave River, immediately downstream of the recharge area, can recover and deliver the stored water through pipelines directly to local urban water retail suppliers. Current beneficiaries of R-Cubed include Liberty Utilities (Apple Valley), City of Adelanto, City of Hesperia, and Victorville Water District.

Phase 1 of the R-Cubed Project was partially completed in 2013. It currently produces approximately 15,000 acre-feet per year, with expansion plans under consideration.

FIGURE 2-9: R-CUBED FACILITIES
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2.1.5 Regional Climate
Located in the High Desert region of San Bernardino County, the climate in the Mojave Region is more extreme than the lowland areas of Southern California. As is typical of the Mojave Desert, the region is very arid because of the rain shadow effect of the surrounding mountains. The summers are extremely hot and dry with occasional monsoonal thunderstorms that can bring flash flooding and hail. Most of the precipitation happens in the winter, with snowfall possible, although much lighter than what occurs in the surrounding mountains and melting quickly.

The major settlements in the Region are along the Highway 15 corridor which generally parallels the Mojave River, primarily within the southern end of the Region including cities and communities of Hesperia, Victorville, Adelanto, and Apple Valley. Thirty-two miles to the north, also along the Highway 15 corridor, is the City of Barstow. The elevation variance across the Region leads to slight differences in reported climate data for various areas, but not significantly different for purposes of this discussion. Therefore, the following figures report data representing the southern area of the Region (using Victorville), with some discussion of the minor climate differences via reference to conditions in Barstow.

Historical averages show January as the coolest and wettest month, and July as the hottest and driest. The wet season is from December to March with a 30-year annual average rainfall of 5.8 inches for Victorville and 5 inches for Barstow. The annual mean temperature is about 62 degrees, but the High Desert climate leads to extreme temperature ranges with highs during the summer months regularly hitting the upper 90s and lows in winter dropping to averages in the lower 30s.

Other climate characteristics of the Region include monsoonal moisture in the later summer, which can cause thunderstorms. These thunderstorms do not deliver nearly as much rainfall as desert regions further east and the region receives only a small fraction of the annual precipitation compared to the eastern areas. Snowfall in Victorville during the winter, if it occurs, is light and tends to melt before accumulating. Snow in Barstow is much rarer and occurs infrequently. Autumn averages very warm and dry conditions still and becomes cooler by November with rainfall beginning as California’s traditional rainy season begins. Winter conditions usually appear by late November. Spring is usually warm during the days although low temperatures are still quite cool. Rainfall usually tapers off by May.

Figure 2-10 shows the average monthly temperature, rainfall, and evapotranspiration (ETo) for the service area. This figure reports data from Victorville. Actual annual rainfall totals deviate quite significantly from the 30-year average as illustrated in Figure 2-11. In most years, precipitation totals fall below the mean.
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FIGURE 2-10: AVERAGE CLIMATE CONDITIONS
FIGURE 2-11: ANNUAL PRECIPITATION VARIABILITY (1996-2024) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Temp 46.5 48.6 53.5 58.5 66.4 75.0 81.9 81.0 74.9 64.0 53.1 45.7 Precip 0.82 1.15 0.56 0.31 0.09 0.02 0.20 0.24 0.18 0.34 0.36 1.04 ETo 2.26 2.96 4.91 6.45 8.00 9.11 9.58 8.90 6.62 4.57 2.79 2.01 0 2
4 6
8 10
12 0
10 20
30 40
50 60
70 80
90 January February March April May June July August September October November December Precipitation, ETo (inches)
Mean Monthly Temp (°F)
Temp (degrees F) Precip (inches) ETo
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2.1.5.1 Climate Change
The CWC does not prescribe specific climate change planning and management measures for water suppliers; however, urban water suppliers should consider climate change when evaluating water supply availability and customer water use trends. For example, drier conditions or drought can lead to more residential irrigation and increased water use compared to wetter years.

Climate change will likely alter precipitation patterns, resulting in consequential externalities like reductions in Sierra Nevada snowpack. Given the region's reliance on imported water, particularly from the State Water Project, which relies on melting snowpack, any effect from climate change on Sierra Nevada snowpack levels and inflows to Northern California reservoirs and the Delta will have a serious impact on water availability. As shown by the trendlines in Figure 2-12, the region has experienced gradual warming in average temperatures over the last 100 years. Increasing temperatures locally within the Region can result in higher evapotranspiration, leading to additional water demand. Although annual median precipitation levels remain relatively consistent, projected changes in the frequency, magnitude, and volume of precipitation show large variability, which has implications for uncertainties in stormwater runoff and peak flow rates.

FIGURE 2-12: HISTORICAL ANNUAL TEMPERATURE AND TRENDS (YEARS) 405
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2.1.6 Current and Projected Population
Service area population and land use projections are critical to developing a useful planning framework as population dynamics and growth are a primary influence on water use within the Mojave Region. These projections directly influence planning measures for system supply, delivery, infrastructure, and demand management. The projections also provide the Region with the necessary data-driven means for assessing whether MWA is accomplishing its purpose of providing sufficient water to meet the Region’s current and future needs.

Similarly, the Region’s economic, social, and demographic trends provide valuable insight to water management and planning. This sub-chapter of the RUWMP addresses these factors to provide a supportable basis for forecasting future water use.

2.1.6.1 Current Population and Historical Trends
The Mojave Region has undergone a dramatic demographic transformation over the past century. In the early 20th century, the Region was sparsely populated, with an economy anchored by agriculture and the railroads, supporting only modest communities in Barstow and the Victor Valley. Following World War II, the Region began developing as Southern California’s suburban boom began pushing development eastward from Los Angeles into the Inland Empire. However, it was the housing affordability crisis in coastal California during the 1980s and 1990s that truly ignited the region’s expansion, as middle-class families sought more affordable housing opportunities. Relatively affordable housing continued to drive growth through the early 2000s, as the City of Victorville and neighboring communities in the Victor Valley entered a period of explosive residential growth, with tens of thousands of new residential homes constructed across former scrubland. This rapid expansion, however, came with significant challenges, including long commutes to employment centers, infrastructure strain, and acute vulnerability during the 2008 Housing Crisis.

The Region slowly recovered following the 2008 housing crisis, fueled by a booming logistics and warehouse industry and a rebounding real estate market. Much of this growth has been concentrated along the Interstate 15 corridor as fulfillment centers and warehouse operations locate themselves near highways and the railroads. Another notable incident was the COVID19 pandemic that brought an unexpected tailwind to the Planning Area as remote work flexibility and record low interest rates allowed more households to acquire affordable housing in the High Desert. Taken together, the Planning Area’s growth has stabilized in recent years, with population and sprawl tempered by water conservation and growth limitations.

In terms of population, the estimated population of the Region in 2025 was 586,000. This accounts for 26% of the total population San Bernardino County and a 19.6% increase from MWA’s 2020 UWMP population for the Region of just over 490,000.

This is a significant increase from the turn of the 21st Century when the Region only accounted for 16% of the County’s entire population. There was a sizable migration into the 406
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Region’s incorporated cities between 2000 and 2010; their annual average growth rate outpacing the overall County rate of 1.9%. Between 2011 and 2019, that growth rate slowed to

1.1% for Adelanto and 1.0% for Victorville, still outpacing the 0.8% rate for the County. Table 2-3 provides a representation of the Region’s population over the past several decades.

TABLE 2-3: HISTORICAL POPULATION7
1990 2000 2010 2020 2025
266,232 321,264 453,649 507,000 586,000

2.1.6.2 Projected Population
As part of its 2020 Urban Water Management Plan (UWMP) development, MWA commissioned a population forecast by the Center for Economic Forecasting and Development at the University of California, Riverside, which was completed in 2020 (UCR Study or Beacon Economics Study). The population forecast provided population estimates for the entire Mojave Region, organized in multiple ways, as estimates for the large urban water retail suppliers, incorporated cities, and adjudicated subareas within the MWA service area. The following sections detail the population projections built from the UCR Study and subsequently used to estimate water use within the expansive Mojave Region.

Methodology
The UCR Study estimated that the Region’s population would increase by 39% over the next 35 years, surpassing San Bernardino County’s projected 21% increase as well as the State’s 13% increase for the same period – resulting in a population increase of about 200,000 people by 2065.8Absent an updated UCR Study but given the release of 2020 Census data subsequent to the UCR Study’s completion, a review and update to the UCR Study was warranted to allow updated forecasts for this RUWMP. An update to the UCR Study and comparison with Southern California Association of Governments (SCAG) data was undertaken as follows:
• 2020 Census Data Update – The UCR Study’s 2020 incorporated city population totals were compared to the subsequently available 2020 Census values, organized for the same incorporated city areas. This comparison allowed for differences between the two datasets to be captured and ultimately resulted in the derivation of refined population projections for the large urban water retail suppliers and the remaining 7 The 2020 and 2025 population values for the Mojave Region reflects the refined UCR Study projections described in the later portions of this chapter.
8 The UCR Study projected the Region’s population to increase by approximately 205,284 people by 2065.

Note: this estimation was derived prior to the release of 2020 Census population data. 407
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portion of the Region to reflect actual 2020 populations. This update is referred to as the Adjusted UCR Study.
• Alternative Data Comparison – The original UCR Study values as well as Adjusted UCR Study values were compared with projections from the SCAG. This comparison focused on assessing whether the magnitude of projected population growth within the Region by the Adjusted UCR Study was adequately characterized. 2020 Census Data Comparison
As depicted in Table 2-4, the 2020 Census population totals for five of the six incorporated cities within the Mojave Region were greater than their respective UCR Study population totals, with differences ranging from 2% to 6%. These differences were used to adjust the UCR Study population projections of the six large urban water suppliers associated with these particular incorporated cities (Table 2-5). The remaining six large urban water suppliers that do not serve an incorporated city were not adjusted as part of this validation since Census data is not available at the water retailer service area boundary level. Furthermore, the six large urban water retail suppliers associated with this adjustment collectively represent 96% of the total projected growth between 2020 – 2065.9
Lastly, the refined population projections presented in Table 2-5 were used to adjust the UCR Study population projection of the entire Region, as depicted in Table 2-6.

TABLE 2-4: COMPARISON OF INCORPORATED CITY POPULATION DATA 9 The projected growth rate referenced is from the un-adjusted UCR Study population projections.

Incorporated City 2020 UCR 2020 Census
Percent
Difference
Adelanto 35,800 38,000 6%
Apple Valley 74,200 75,800 2%
Barstow 24,200 25,400 5%
Hesperia 97,800 99,800 2%
Victorville 127,700 134,800 6%
Yucca Valley 22,200 21,700 -2%
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TABLE 2-5:URBAN WATER SUPPLIER POPULATION PROJECTIONS –UCR STUDY AND ADJUSTED UCR STUDY10 TABLE 2-6: MOJAVE REGION POPULATION PROJECTIONS –UCRSTUDY AND ADJUSTED UCR STUDY 10 The following six water districts which do not supply an incorporated city did not have their population projections adjusted as part of the population validation: Bighorn-Desert View Water Agency, County Service Area 64, County Service Area 70 J, Helendale CSD, Joshua Basin Water District, and Phelan Piñon Hills CSD.

Large Urban Water
Retail Supplier
UCR Study Adjusted UCR Study
2020 2065 2020 2065
City of Adelanto 35,800 52,100 38,000 55,200
Liberty Utilities - Apple Valley Water
Company 62,100 80,900 63,300 82,500
Golden State Water Company -
Barstow System 32,200 35,100 33,800 36,900
Hesperia Water District 97,400 151,400 99,300 154,500
Victorville Water District 134,300 228,100 142,300 241,700 Hi-Desert Water District 25,700 31,000 25,100 30,300
Bighorn-Desert View Water Agency 4,100 4,600 N/A N/A
County Service Area 64 11,200 13,700 N/A N/A
County Service Area 70 J 10,200 11,500 N/A N/A
Helendale CSD 6,600 7,300 N/A N/A
Joshua Basin Water District 10,200 11,300 N/A N/A
Phelan Piñon Hills CSD 20,800 23,000 N/A N/A
UCR Study Adjusted UCR Study
2020 2065 2020 2065
492,000 698,000 507,000 722,000
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Comparison to SCAG
The Adjusted UCR Study population projections were compared to population projections found in the 2024 SCAG SoCal Connect Report.11 The purpose of this comparison was to ensure that the magnitude of the Adjusted UCR Study projected population growth as used for this RWUMP was within a reasonable range of SCAG’s projections, which used a different analysis and forecast method than the UCR Study. As depicted in Table 2-7, the SCAG provided a population projection specific to the Region through 2050.

TABLE 2-7: ADJUSTED UCR STUDY AND SCAG POPULATION PROJECTIONS Results
The intent of the update and comparison was to provide confidence for a population projection critical to the water demand forecast method further described in Chapter 4 – Water Use Characterization. Population data is a key indicator used to understand per-capita demand and thus becomes the source for demand forecasts when more specific housing developments are less clear. For purposes of the RUWMP, the Adjusted UCR Study projections are used for each participating retail urban water supplier and for MWA, with the latter reflecting all the remaining small water suppliers and rural domestic users that are reliant on the water resources available to the Region. Table 2-8 summarizes the population estimates for each participant.
11 Link to the 2024 SoCal Connect Report: https://scag.ca.gov/connect-socal-2024-read-draft-plan. The SCAG SoCal Connect Report is updated every four years and utilizes 2020 Census data as an input for establishing its population projections.

Mojave Region 2020 2050 2065
Adjusted UCR Study 507,000 673,000 722,000
SCAG 498,000 638,000 N/A
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TABLE 2-8: 2025 RUWMP POPULATION PROJECTIONS

2.1.7 Land Use, Economy, and Demographics
Land use in the Mojave Region is undergoing a fundamental shift from its historical agricultural roots toward rapid urbanization and industrial expansion. The region’s once thriving agricultural sector has declined as developmental pressures and geographic 12 Projected population estimates for the City of Victorville presented in this table were further refined by the City using the methodology described in its retail-chapter. 13 The Mojave Water Agency population shown in this table represents the portion of the Mojave Region located outside the service areas of the participating urban water retail suppliers. The projected decline reflects the assumption that future population growth will be increasingly served within the urban water retail supplier service area, rather than by areas represented under MWA’s wholesale population category.

Agency 2025 2030 2035 2040 2045 2050 2055 2060
City of Adelanto 44,588 45,913 47,239 48,565 49,890 51,216 52,542 53,867 County Service
Area 64 11,691 12,099 12,390 12,646 12,884 13,103 13,304 13,490 County Service
Area 70J 10,356 10,554 10,721 10,876 11,021 11,153 11,275 11,387 GSWC
Barstow 35,947 37,744 39,542 43,137 46,731 54,209 57,861 61,513 Hesperia Water
District 120,530 124,771 129,012 133,252 137,493 141,733 145,974 150,214 Hi-Desert
Water Agency 27,139 27,538 27,938 28,338 28,737 29,137 29,537 29,937 Joshua Basin
Water District 10,375 10,536 10,673 10,800 10,919 11,029 11,131 11,225 Liberty Utilities
Apple Valley12 70,707 72,184 73,661 75,138 76,615 78,092 79,569 81,045 Phelon-Piñon Hills
CSD 21,136 21,465 21,744 22,003 22,245 22,469 22,676 22,869 Victorville Water
District 148,323 157,229 166,135 175,042 183,948 192,855 201,542 210,689 Mojave Water
Agency13 85,602 84,485 83,152 79,907 76,230 68,100 64,002 59,422 Total Region 586,395 604,519 622,207 639,704 656,713 673,095 689,412 705,659 411
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proximity to Southern California have transformed the High Desert into a major commuter community and logistics hub. Broad land use trends reflect a mix of continued suburban growth, logistics and industrial expansion, and large-scale renewable energy development.

Incorporated communities such as Hesperia, Victorville, Apple Valley, and Adelanto have seen ongoing residential development, particularly single-family residential housing, driven by relatively affordable housing. At the same time, the Interstate 15 corridor has attracted significant warehouse, distribution, and manufacturing projects due to regional freight movement between Southern California and the Inland Empire, reinforcing the High Desert’s role as a logistics hub. In outlying areas, land use has increasingly shifted toward utility-scale solar energy and related infrastructure, supported by state renewable energy policies and the availability of large tracts of land. However, growth is occurring alongside planning efforts tied to groundwater sustainability in the Mojave River Basin, which are influencing development patterns, water supply planning, and the pace of new projects, particularly in communities that rely heavily on groundwater in overstressed portions of the Region’s many groundwater subbasins.

This transition is fueled by the Region’s relatively affordable housing and its strategic location along major interstate and rail corridors, leading to a projected 40% population increase over the next four decades that continues to transform the High Desert from rural to urban.

Specific land use and demographic trends are discussed in each individual retailer’s chapter.

This sub-chapter provides a region-wide outlook on its land use and demographic trends over the last several decades to present-day.

2.1.7.1 Current and Projected Land Use
Anchored by the rapidly growing incorporated communities of Victorville, Hesperia, and Apple Valley, the region continues to attract large master-planned residential developments and millions of square feet in new industrial and logistics facilities, fueled by affordable land and strategic infrastructure access. Utility-scale solar energy projects are simultaneously converting vast stretches of desert land to solar farms. The planned high-speed Brightline West rail station in Apple Valley is expected to further accelerate transit-oriented growth in the region. Underlying all these planned growth trends is a critical constraint: the basin’s groundwater supply.

Trends in future land use will be largely influenced by urbanization as more of the High Desert landscape is transformed into residential developments. Most residential development will be concentrated in the communities in the surrounding Victor Valley at the southern end of the Region, and in and around the City of Barstow. These two growth areas are also the region’s largest economic engines, where the region’s burgeoning logistics and transportation industries are expanding. In addition to these broader trends, several large-scale development projects have been identified that are expected to further accelerate growth within the Region. As shown in Table 2-9, these projects are anticipated to significantly 412
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influence population growth, job creation, and land use patterns, and have been incorporated into the population and water demand projections that underpin this RUWMP.

TABLE 2-9: KNOWN LAND USE PLANS IN THE MOJAVE REGION

2.1.7.2 Economic Trends and Other Social and Demographic Factors
California’s High Desert region, anchored by the Cities of Victorville and Barstow, is one of the state’s most consequential emerging growth corridors. Since the end of the Great Recession, it has seen some of the strongest employment growth in California, with the third largest workforce of the state’s metropolitan areas. Straddling the convergence of Interstate 15 and Interstate 40, the region sits at a geographic crossroads between Greater Los Angeles, the Las Vegas metro, and the broader American Southwest. What was once characterized primarily as a pass-through zone, famous for Route 66, is now experiencing a structural economic transformation driven by a booming demand for logistics and warehouses, affordable housing, and multiple landmark infrastructure projects that stand to reshape the Region’s role in the national supply chain and passenger mobility network.

The most consequential economic development in the region is the emergence of largescale logistics and warehousing infrastructure, driven by the exhaustion of industrial land in the traditional Inland Empire to the south and the availability of vast, inexpensive parcels in the High Desert. Over the last four years, approximately 4.5 million square feet of new industrial construction has been completed in the High Desert. Major investors include Prologis, Clarion, and LINK, with significant leasing activity from Amazon and Home Depot. The City of Victorville recently welcomed a 1.3-million square foot Goodyear Tire distribution center and an Amazon Fulfillment Center at the Southern California Logistics Airport (SCLA), with additional industrial projects totaling over 1.35 million square feet planned along Mojave Drive. The SCLA is already home to Boeing and General Atomics, giving it a dual identity as both an aerospace hub and an e-commerce distribution node.

Railroads have long played a foundational role in the economic development of the High Desert. The Cities of Barstow and San Bernardino first emerged as railroad hubs for local farmers to ship agricultural goods to market and as stopovers for trains heading into the Los Existing or Planned Project Project Area (acres) Residential Housing Units BNSF Barstow International Gateway 4,500 N/A
Brightline West Station 300 N/A
Rancho Lucerne Planned Development 1,376 4,257
Silverwood Specific Plan 9,336 15,663
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Angeles Basin. Recently, railroads have re-emerged as a transformative force in the region’s economy with the advent of the BNSF Barstow International Gateway (BIG) and the Brightline West high-speed rail line. BNSF Railway has announced plans to invest more than $1.5 billion in a master-planned rail facility designed to revolutionize cargo movement from Southern California ports. BIG will integrate a rail yard, intermodal facility, and warehouses to transfer containers directly from ships to rail for inland transit. It will directly connect the Ports of Los Angeles and Long Beach to Barstow via rail, allowing for faster transit of goods to the rest of the US. By moving containers by rail rather than trucks, BIG aims to reduce freeway traffic and cut emissions while creating 20,000+ jobs. Upon completion, BIG will be the largest intermodal transportation hub in North America – twice as large as any existing facility.

Passenger rail in the High Desert region anticipates a major tailwind from Brightline West. The privately financed 218-mile high-speed passenger rail line will connect Las Vegas to Rancho Cucamonga, with two planned railway station stops in Apple Valley and Hesperia. The project broke ground in 2024 and is projected to begin passenger service by 2028, with construction expected to generate more than 10,000 jobs and 1,000 permanent jobs. The Victor Valley station in Apple Valley is designed to accommodate commuter rail use, allowing High Desert residents to access employment in the Inland Empire and Los Angeles Basin at lower housing costs – a pattern that could accelerate population growth and transit-oriented development around the station.

Affordable housing is a critical driver of economic growth in the High Desert. As housing costs in coastal Southern California markets continue to rise, the High Desert has emerged as a population residential alternative for moderate household incomes. This popularity and proximity have spawned a large commuter population that works in nearby Los Angeles and Orange Counties. The number of residents commuting to jobs in neighboring counties is expected to increase in the near-term as housing prices continue to rise and supply remains constrained. Despite benefiting from population growth linked to affordable housing and commuters, the High Desert faces several structural economic and fiscal risks. With such a large proportion of the population commuting to coastal job centers in Los Angeles and Orange County, downturns in those economies can quickly ripple inland, reducing household income and housing stability. Moreover, dependence on commuters can distort land use and housing patterns. Effectively a “bedroom community,” where housing growth outpaces job creation, this imbalance can make it harder to attract employers seeking proximity to locally available workforce. However, the rise in remote workers and multiple major infrastructure developments have the potential to disrupt the High Desert’s legacy status as a bedroom community into a burgeoning employment hub.

The High Desert is at an inflection point. Victorville has already become a significant logistics and population center, the fastest-growing large city in inland Southern California, though its economic gains are concentrated in lower-wage warehouse and distribution work rather than higher-value sectors that would diversify and deepen its tax base. Generally, the Region has experienced strong job growth and sectoral restructuring around the logistics industry, shaped by both regional dynamics in the High Desert and broader economic shocks such as 414
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the COVID-19 pandemic. Over the past decade, the employment growth rate for non-farm labor in the San Bernardino County outpaced all other regions in Southern California and sustained less economic impact from the Covid-19 recession than Los Angeles, Orange, or San Diego Counties (Figure 2-13). Logistics, driven by the rise of e-commerce and the region’s transportation infrastructure, has been the dominant sector, growing by approximately 80% over the decade, while healthcare and education have grown by roughly 30-40%, reflecting population growth and increasing service demand. These trends highlight a broader structural shift toward a service and distribution-oriented economy, with logistics serving as the region’s primary economic engine.

At the same time, the labor market has shown improving stability compared to earlier decades. Unemployment rates, which were historically elevated in the Inland Empire, declined significantly following the post-Great Recession recovery and remained relatively moderate in the late 2010s. Although unemployment spiked sharply during the pandemic, reaching nearly 10% in 2020, the county experienced a strong recovery, with rates falling back to around 5% by 2024–2025, near statewide averages. This indicates a resilient labor market capable of rebounding from economic disruptions. However, more recent data suggest emerging signs of slowing growth and sectoral unevenness. Between 2022 and 2023, some key sectors, including logistics, manufacturing, and professional services, experienced modest employment declines, while healthcare and education continued to expand. This divergence reflects both post-pandemic normalization, particularly in goods movement, and broader economic headwinds affecting higher-wage industries.

Another defining feature of the past decade is the region’s continued reliance on lower-wage and goods-moving sectors, even as wages have begun to rise across industries. While salary growth has been notable, especially in professional and healthcare fields, job concentration in logistics and warehousing has reinforced concerns about job quality and economic diversification. Overall, the High Desert has grown significantly and become more diversified over the past decade. Between the region’s two largest cities, Victorville and Barstow, the High Desert is poised to leverage its emerging logistics industry and affordable housing stock to become a prosperous regional economy with its own identity. 415
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FIGURE 2-13: SAN BERNARDINO COUNTY EMPLOYMENT DATA 2015-2025

2.1.8 Summary
The Mojave Region is one of the fastest growing regions in California. As discussed, relatively affordable housing and strategic infrastructure corridor access continue to accelerate population and economic growth. However, limited water supplies, further exacerbated by mounting hydrological and regulatory limitations, continue to adversely constrain the Region.

Adequate water supplies and long-term resource management are paramount to the region’s outlook. This 2025 RUWMP helps MWA and the large urban water retail suppliers coordinate and collectively plan to meet an optimistic future condition. 416
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Chapter 3.0 REGIONAL WATER SUPPLY

CHARACTERIZATION
This chapter describes the Mojave Region’s water supply sources, which include imported surface water supplies managed by the Mojave Water Agency, and local surface and native groundwater supplies managed collectively by MWA, retail water suppliers, and designated watermasters in the adjudicated areas of the Region.

The more specific characterization of water available for import is presented in Chapter 6 - Mojave Water Agency, while the detailed characterization of retailer-specific groundwater is discussed within each urban water retail specific chapter (Chapters 7 through 16).

The available regional supplies discussed in this chapter reflect a summary of the more specific MWA and retailer supply conditions and are organized into the three Subregions described in Chapter 2 – The Mojave Region. Organizing supplies for each specific subregion facilitates the integration with subregional demands (Chapter 4 – Water Use Characterization), providing for supply reliability analysis to be presented by subregion (Chapter 5 – Regional Water Service Reliability). This subregional approach allows the entire Mojave Region to be viewed in a more aggregated form, while still reflecting important geographic, hydrologic and management circumstances that are lost if the analysis were completed for just the entire Mojave Region. Each of the retailer-specific chapters (Chapters 7 through 16) reflect each retailer’s reliance on the managed groundwater that results from two primary categories: (1) annually available sources including State Water Project (SWP) imports delivered through six turnouts on the East Branch of the California Aqueduct and subsequently recharged throughout the region, and (2) groundwater supplies comprised of natural recharge from the Mojave River and San Bernardino Mountains, return flows from water use, and imported wastewater from mountain communities. Recycled water is an important third component that is being deployed within the Mojave Region at the urban water retail supplier level and will continue to expand as an important supply source into the future.

3.1.1 Mojave Region Water Supply Sources
As described in Chapter 2 – The Mojave Region, the Mojave Region is situated in the High Desert of eastern San Bernardino County in a mostly closed topographic basin where water 417
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supply is derived almost entirely from pumped groundwater from the various basins, subbasins and aquifers within its service area. Beyond the minimal precipitation in the Region, natural recharge of the aquifers occurs primarily from flows originating in the San Bernardino Mountains to the south that infiltrate into the basin-fill sediments along the mountain front. The Mojave River also contributes to groundwater recharge through streambed infiltration during wet periods and after significant mountain snowmelt that flows to the Mojave River and its tributaries. Augmentation of the native groundwater is dependent on State Water Project imports and transfers and exchanges conveyed to the Region.

Additional local groundwater recharge occurs from irrigation return flows, wastewater imports, and recycled water.

The system is essentially a large underground reservoir where water moves slowly through interconnected aquifers creating the vital water supply for the region. For purposes of this RUWMP, water supplies available to the Region fall into the following major categories, each of which is described in detail throughout this chapter:
• Groundwater
• Imported Water
• Return Flows
• Treated Wastewater and Recycled Water
• Water Transfers and Exchanges
• Planned Water Suppliers

3.1.1.1 Groundwater
Groundwater is the principal source of municipal water supply in the Mojave Region. All retail water suppliers operating within the Region rely on managed groundwater – a blend of natural inflows and recharged imported water – to meet current and projected demand. As noted above, the MWA supports groundwater management in the Region by importing water supplies that are used to replenish groundwater extractions and help manage groundwater basin health.

Natural inflows into the groundwater aquifers are fed through direct percolated precipitation across the basin area and infiltration and storm runoff into stream systems during wet weather. The primary source of natural inflow is infiltration of stormflow runoff water from the San Bernardino Mountains into the Mojave River. The Mojave River is formed by the confluence of the West Fork Mojave River and Deep Creek, both originating in the northwestern San Bernardino Mountains. This mountain-front recharge provides the majority of natural groundwater replenishment to the basin and enters the system in the Alto subarea.

During Water Year 2024, natural water supplies exceeded historical averages, with total flow at the Mojave River Forks reaching 102,389 acre-feet. After accounting for 14,825 acre-feet of 418
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SWP water that MWA imported to the West Fork Mojave River system, natural inflow was measured at 87,564 acre-feet compared to a Base Period average of 65,540 acre-feet.

Despite this above-average year, the Region continues to experience long-term drought impacts, with native water supply conditions over the past 13 years averaging only 69.4% of the historical baseline (1931-1990).

As mentioned in Chapter 2, the Mojave Region overlies all or a portion of 36 groundwater basins and subbasins, as presented in Figure 2-5. Those situated along the Mojave River and adjacent areas are collectively referred to as the Mojave River Groundwater Basin, otherwise known as the Mojave Basin Area. The remaining basins in the southeastern portion of the Region are generally designated as the Morongo Basin/Johnson Valley Area (Morongo Area), with the exception of the Lucerne Valley, which is treated as a distinct management unit.

MWA characterizes a long-term average of the natural supplies for the region, including both the Mojave Basin area and the Morongo Basin Area, as 57,349 acre-feet per year. This value is derived from previous assessments of natural supply available and groundwater basin conditions.

Most groundwater production in the Region relies on three primary aquifers: the Floodplain Aquifer, Regional Aquifer, and Morongo Aquifer (Figure 3-1). Each aquifer system has distinct hydrogeologic characteristics and recharge mechanisms. The Floodplain Aquifer is composed of sand and gravel weathered from metamorphic and granitic rocks of the San Gabriel and the San Bernardino Mountains, respectively, and deposited in a fluvial environment. Recharge occurs primarily through direct infiltration of Mojave River surface flows during the wet season, with the greatest recharge rates occurring near the mountain front where surface flows are most frequent and vigorous.

The Regional Aquifer underlies and surrounds the Floodplain Aquifer, comprising interconnected alluvial fan and basin fill deposits. Its primary recharge source is groundwater migrating laterally from the Floodplain Aquifer. Additional recharge is contributed by runoff from the higher elevations of the San Gabriel and San Bernardino Mountains, supplemented by smaller runoff volumes from local ephemeral streams and desert washes.

The Morongo Basin Area encompasses several interconnected basins in southern San Bernardino County. It is a vital water source, managed by the MWA and the local retail water suppliers, for the benefit of communities in the eastern portion of the Region. Groundwater supplies in the Morongo Area are supplemented by imported water conveyed through the 71- mile Morongo Basin Pipeline (MBP) that delivers water from the SWP’s California Aqueduct to recharge basins in the Morongo Basin Area. The MBP serves a dual purpose: reducing overdraft in the Warren Valley Basin and Ames Valley Basin, and supporting groundwater 419
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levels in the Joshua Tree Basin (see Chapter 2 – The Mojave Region).14 Groundwater flow in the Morongo Area is complex but is generally from south to north in Johnson Valley and from west to east-northeast elsewhere in the area. Natural recharge originates primarily from the mountains on the southern and western boundaries of the Morongo Area, resulting in groundwater flow gradients to the north, east, and south adjacent to the boundaries, before turning to the east-northeast. Groundwater flow is complicated locally by pumping, faulting, shallow bedrock, and enhanced recharge basins. For example, in the vicinity of the developed area of Yucca Valley, groundwater flow is controlled to some extent by local recharge basins.

FIGURE 3-1: FLOODPLAIN AND OTHER REGIONAL AQUIFERS
14 The following agencies jointly financed the MBP and currently rely on it for portions of their water supply:

Hi-Desert Water District, Joshua Basin Water District, Bighorn-Desert View Water Agency, and CSA 70 W-4 Pioneer Town
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3.1.1.2 Groundwater in the MBA Judgment Area
The MBA Judgment (see Chapter 2 – The Mojave Region) established a Production Safe Yield (PSY) system that defines sustainable groundwater pumping levels for each Subarea subject to the Judgment. Specifically, PSY is defined as the maximum production level that can be maintained over a sequence of years representative of long-term average natural water supply conditions, accounting for natural outflow, and under established patterns of water production, applied water, return flows, and consumptive use, while ensuring no long-term net reduction in groundwater storage. The MBA Judgment also assigned Base Annual Production (BAP) rights to each producer using 10 acre-feet or more, based on historical production during the period 1986-1990. Parties to the MBA Judgment are assigned a variable Free Production Allowance (FPA), which is a percentage of the BAP set annually by the Court for each Subarea based on the recommendation of the Watermaster. The BAP is reduced or “ramped-down” over time until FPA comes within 5% of the Judgment-defined PSY. The FPA changes over time as the MBA Watermaster assesses supply availability for all adjudicated purveyors against the long-term health and PSY.

The FPA is set as follows for each Subarea for water year 2025-2026:15 • Alto Subarea – 50.4% of BAP
• Oeste Subarea – 45% of BAP
• Este Subarea – 45% of BAP
• Centro Subarea – 56% of BAP
• Baja Subarea – 19.5% of BAP
Any Producer that pumps more than their FPA must purchase Replacement Water from the Watermaster equal to the amount of production in excess of their total available FPA or transfer unused FPA from another party within their Subarea. Funds collected for Replacement Water are then used by MWA for purchase of SWP supplies and recharged into the Subarea they were produced from. In addition to purchasing water to offset the Replacement Water Obligations under the Judgment, MWA purchases and stores water in the Mojave Basin Area for future obligations (see Chapter 6 – Mojave Water Agency).

In Chapters 7 through 16, the projected FPA for each urban water retail supplier participating in the 2025 RUWMP, consistent with the UWMPA requirements, is provided. 16 Using the
Subregions described in Chapter 2 – The Mojave Region, the summary of available native groundwater is presented in Table 3-1. These totals represent the native groundwater (i.e.

FPA) in Subregions 1 and 2 and are inclusive of FPA available to the urban water retail 15 Water Year 2024-2025 Mojave Basin Area Watermaster Annual Report, June 2026 16 For instance, see values for Hesperia Water District in Table 11-8 and Table 11-9 in Chapter 11 – Hesperia Water District.
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suppliers participating in the 2025 RUWMP as well as all other groundwater users within each subregion outside of a participating retailer’s service area.

TABLE 3-1: PROJECTED NATIVE GROUNDWATER FOR EACH SUBREGION THROUGH 2050 (AFY)

3.1.1.3 Groundwater in the Morongo Subarea
As described in Chapter 2 – The Mojave Region, the Morongo Subarea encompasses both the Ames Valley Judgment and the Warren Valley Judgment. While these Judgments function differently than the MBA Judgment, they reflect conditions where native groundwater use exceeded natural recharge. Unlike the MBA Judgment Area, the Morongo Subarea does not have a single regional framework that establishes a quantified native groundwater production allowance appliable across all basins and users. The Morongo Subarea is composed of multiple groundwater basins with varying levels of development, monitoring, adjudication, and management. As a result, the amount of native groundwater reasonably available across the entire Morongo Subarea is not conclusively quantified for purposes of this RUWMP.

3.1.1.4 Imported Water
MWA relies on a diverse portfolio of imported surface water supplies. Imported water is delivered to the Mojave Region via the SWP California Aqueduct. As one of 29 SWP Contractors, MWA’s primary imported supply source is its Annual Table A Allocation, followed by supplementary supplies obtained by various contractual agreements, transfers, and exchanges. Upon delivery of imported water, by the East Branch of the California Aqueduct, to the Agency’s service area, MWA delivers this blend of imported water to various recharge sites throughout its service area. Fundamentally, MWA’s mission is to provide the region with imported water to supplement local groundwater supplies and recharge local groundwater basins. A summary of the MWA’s imported water supplies is provided in Table 3-2. Additional details on the SWP supplies and forecast reliability are detailed in Chapter 6 – Mojave Water Agency.

Projected Native Groundwater
For All Year Types
2030 2035 2040 2045 2050
Subregion 1 70,389 70,389 70,389 70,389 70,389
Subregion 2 39,602 39,602 39,602 39,602 39,602
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TABLE 3-2: MWA’S PROJECTED IMPORTED WATER SUPPLIES (AFY) Total Supply Percent
Allocation 2030 2035 2040 2045 2050
Normal 54% 48,492 48,492 48,492 48,492 48,492
Single Dry Year 5% 4,490 4,490 4,490 4,490 4,490 Multi-Year Drought Year 1 35% 31,430 31,430 31,430 31,430 31,430
Year 2 5% 4,490 4,490 4,490 4,490 4,490
Year 3 5% 4,490 4,490 4,490 4,490 4,490
Year 4 20% 17,960 17,960 17,960 17,960 17,960
Year 5 35% 31,430 31,430 31,430 31,430 31,430

3.1.1.5 Return Flows
When water supplies are extracted from the groundwater basins, a portion of the water pumped is consumed and another portion of the extracted water is returned to the groundwater aquifer and becomes part of the available water supply. This “return flow” is an important component of the Region’s managed groundwater supply. For example, nearly all indoor water use is assumed to be returned to the basin either by percolation from septic tanks or treated wastewater effluent produced by municipal wastewater facilities. The MBA Watermaster Report calculates consumptive use for each producer in each Subarea of the MBA Judgment. The calculation is based on production amount, type of use, and an evaluation of processes that consume water.

Return flows shown in Table 3-3 are calculated as a percentage of the previous years’ water production for each water use category, as defined by the MBA Watermaster. Return flow factors, on a regional basis, average approximately 40% of the groundwater production, although this amount can vary significantly by Subarea and on an annual basis. Importantly, as water extractions increase in the Region, the return flows will also increase over time.

However, as system efficiencies improve, return flows may begin to slowly decline.

Nevertheless, for purposes of this 2025 RUWMP, return flows are assumed to be a percentage of the total Water Year Verified Production for each Subarea for the most recent reported Water Year.17 This value is then held constant in all future year types and all years through 2050. A return flow is not calculated for the Morongo Subarea (Subregion 3). 17 Water Year 2024-2025 Watermaster Report, June 2026, Verified Projection by Subarea, Appendix B, p.15 of 16. This methodology is consistent with the investigation of consumptive use by the MBA Watermaster. 423
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While this is a recognized source of water affecting determinations of available FPA within the MBA Judgment Subareas, for purposes of this RUWMP, this supply source is ignored. This is a conservative assumption that allows this value to be refined while the interaction among FPA, Return Flows, and Managed Stored Groundwater continues to be evaluated to avoid inadvertently double-counting supplies in the Region’s overall water reliability assessment.

TABLE 3-3: SUMMARY OF RETURN FLOW FOR SUBREGION 1 AND SUBREGION 2 THROUGH 2050 (AFY) Subregion18 Verified Production Estimated Return Flow
Subregion 1 78,278 31,300
Subregion 2 23,605 9,500

3.1.1.6 Treated Wastewater and Recycled Water
The Region’s self-sufficiency includes development of recycled and reusable water supplies combined with a region-wide emphasis on water use efficiency. Additionally, the Region also accepts treated wastewater imported into certain subareas.

Treated wastewater effluent is imported from three wastewater entities outside the Region.

Specifically, treated wastewater from the Lake Arrowhead Community Services District is imported into the Alto Subarea, while effluent from Big Bear Area Regional Wastewater Agency is imported to the Este Subarea. Wastewater from Crestline Sanitation District is also imported but already accounted for in the natural groundwater recharge. This water is considered indirect potable reuse. The MBA Watermaster recognizes these imports in its annual reporting, recognizing almost 3,400 acre-feet in the Water Year 2024-2025 Report.

However, over half of this came from the Big Bear facility, which is currently implementing a local recycled water program that will result in this source rarely being available to the Region. For the purposes of this 2025 RUWMP, the recycled water is only assumed available to Region 1 and will be limited to approximately 1,200 acre-feet annually (continuing from Lake Arrowhead CSD and Crestline CSD).

The Region also relies upon and anticipates increasing the local recycled water portfolio to provide both direct use, direct recharge, and indirect aquifer replenishment within the Region, particularly in Subregion 1, where the Region’s largest population base drives wastewater generation and, in turn, recycled water supply availability.

The primary recycled water source is the Victor Valley Wastewater Reclamation Authority (VVWRA) with recycled water production from its Regional Water Reclamation Plant (Regional 18 As discussed in Chapter 2 – The Mojave Region, Subregion 1 includes the Alto, Este, and Oeste Subareas while Subregion 2 includes the Centro and Baja Subareas. 424
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WRP) and two additional Subregional WRPs, one in Hesperia, and one in Apple Valley. There are currently five permitted recycled water users in the service area: American Organics, the City of Victorville, High Desert Power Plant, the City of Hesperia, and the Town of Apple Valley.19 The VVWRA also contributes recycled water through wastewater effluent discharges to the Mojave River to replenish the downstream aquifer and to support the riparian corridor that lies within the Alto Transition zone. In the Water Year 2024-2025 Watermaster Report, Victorville and VVWRA contributed approximately 14,000 acre-feet of recharge to the Mojave River. While only permitted to discharge 14 million gallons per day (MGD)20, the main Victorville facility is designed to produce up to 22 MGD of water and is capable of discharging up to 18 MGD. The Apple Valley21 and Hesperia22 facilities are designed to be operational in phases, with Phase I having a capacity of 1 MGD, Phase II having a capacity of 2 MGD, and Phase III having a capacity of 4 MGD. Water from the main VVWRA facility is used to both provide flows in the Mojave River and recharge the aquifer as well as cooling in a nearby power plant. The Hesperia Subregional facility is used for irrigation at the Hesperia Golf Course and local area parks (see Chapter 11 – Hesperia Water District). The Apple Valley Subregional Facility at Brewster Park is expected to produce irrigation water for Brewster Park, the Civic Center and Apple Valley Golf Course among other locations.

Recycled water is subject to certain restrictions within the law, and localized use requires specific infrastructure investments. The recycled water facilities are governed by National Pollutant Discharge Elimination System (NPDES) permit restrictions. Additionally, the facilities are permitted only for the following beneficial uses: Municipal and Domestic Supply, Agricultural Supply, Industrial Service Supply, Freshwater Replenishment, and Aquaculture.

Future recycled water projects will play a central role in enabling the Region to continue demonstrating reduced reliance on Delta imports.

For the purposes of this 2025 RUWMP, Subregion 1 will conservatively only represent the estimated recycled water volume that is available to Hesperia Water District and the City of Victorville, as further detailed in their individual retail chapters. Table 3-4 presents projected recycled water supplies for Subregion 1 through 2050.

TABLE 3-4: RECYCLED WATER SUPPLIES FOR SUBREGION 1 THROUGH 2050 (AFY) 19 VVWRA 2024 Annual Recycled Water Report, Table 2.
20 https://www.vvwraca.gov/home/showpublisheddocument/194/637694937439730000 21 https://www.vvwraca.gov/home/showpublisheddocument/200/637694940317370000 22 https://www.vvwraca.gov/home/showpublisheddocument/204/637694942003170000 Subregion 2030 2035 2040 2045 2050
Subregion 1 2,004 3,238 3,834 4,408 4,908
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3.1.1.7 Water Transfers and Exchanges
As discussed in Chapter 6 – Mojave Water Agency, MWA engages in water transfers and exchanges involving its SWP assets and other SWP Contractors’ SWP assets. Historically, MWA has both received and delivered water through these transfers and exchanges with various agencies throughout California. These transfers are essentially spot market transfers where short-term opportunities are identified and then actions taken for purchase and acquisition.

These transfers help support management of MWA’s and its retail agencies’ water supply portfolios. Future MWA transfers and exchanges depend upon allocations available to MWA and other water purveyors and are not considered an available supply for purposes of this RUWMP.

3.1.1.8 Planned Water Supplies
Potential future water supply projects, supplementary to existing supplies, consist of the MWA’s participation in Sites Reservoir, Delta Conveyance Project, and potential recharge projects. All of these focus on helping MWA improve the reliability and management of SWP supplies and are discussed in more detail in Chapter 6 – Mojave Water Agency.

3.1.2 Water Quality
Water quality is a critical consideration in the Mojave Region. Because local potable supplies are derived from blended groundwater sources, well locations, recharge activities associated with imported water, and other key system components are actively coordinated and managed among participating retailers and MWA.

3.1.2.1 Imported Water Quality
Generally, the imported surface water conveyed through the California Aqueduct and recharged throughout the Region is considered to be good quality. Many retailers rely on the imported supplies to help manage the quality of water delivered to customers, using the benefits of the imported water as a blending supply to the native groundwater. Water quality delivered to the Region is monitored by the DWR Division of Operations and Maintenance within the California Aqueduct. More details regarding the specific quality information are included in Chapter 6 – Mojave Water Agency.
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3.1.2.2 Groundwater Quality
MWA has implemented a comprehensive groundwater monitoring program to improve understanding of both water quantity and quality across the Mojave Region’s groundwater basins. In coordination with the United States Geological Survey (USGS), this program includes an 850-well monitoring network. Water levels from these wells are recorded on a regular basis and several of the wells are tested for water quality on a rotating sampling schedule.

Numerous studies dating back to the early 1900's have been conducted by various agencies to characterize groundwater quality in the Region and further the understanding of the Mojave River and Morongo Groundwater Basins. The most recent study was the Mojave Salt and Nutrient Management Plan completed in 2015.23 Despite local groundwater quality degradation, these studies generally confirmed the suitability of groundwater for beneficial uses in the Region. Groundwater quality data, including intrinsic tracers, have been used to confirm sources of groundwater recharge and travel times along interpreted flow paths in the Floodplain and Regional aquifers. Investigations have also been conducted to identify the source and occurrence of key naturally occurring groundwater contaminants, including hexavalent chromium (Cr-VI) and arsenic, in the Mojave Desert region.

The impairment of groundwater from the perspective of its beneficial use as drinking water is determined by comparing concentrations of constituents of concern in the groundwater against drinking water maximum contaminant levels (MCLs) and agricultural water quality parameters needed for specific crops. Key groundwater constituents of concern in the Region include arsenic, nitrates, iron, manganese, Cr-VI, fluoride, and total dissolved solids (TDS).

Some of these constituents are naturally occurring in desert environments while others are associated with human (anthropogenic) activities. Measurements exceeding drinking water standards have been found for some of these constituents within the Mojave River Basin and the Morongo Basin. If necessary, groundwater in these areas may require treatment prior to consumption.

MWA’s Salt and Nutrient Management Plan (SNMP) provides an evaluation of potential groundwater quality issues that may result from sources of salts and nutrients. The SNMP addresses whether these constituents would unreasonably degrade groundwater quality and potentially decrease the beneficial uses of groundwater within the basin. For the MWA SNMP, TDS and nitrate were analyzed as appropriate indicator constituents of salts and nutrients.

Total salinity is commonly expressed in terms of TDS as milligrams per liter (mg/L). TDS concentrations in the groundwater are influenced by the chemistry of the aquifer and quality of water recharging the aquifer. TDS is not a health hazard at typical groundwater 23 Relevant water quality studies are available at http://www.mojavewater.org/regional-studies.html.

Hereafter “2015 Salt and Nutrient Plan”).
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concentrations but can be an aesthetic issue and can shorten the useful life of pipes and water-based appliances in homes and businesses. TDS monitoring data are widely available for source waters (both inflows and outflows) in the Region, and because TDS is a general indicator of total salinity, TDS is an appropriate indicator of salt loading. TDS concentrations generally increase in downgradient portions of the Mojave River Basin and along groundwater flow paths away from the primary recharge source in the basin, the Mojave River. Elevated TDS concentrations (greater than 1,000 mg/L) are generally associated with natural processes including mineralization and evaporation beneath dry lake beds. In the Morongo Basin, groundwater TDS concentrations generally increase along groundwater flow paths away from the southwestern margins of the basin where mountain-front recharge occurs.

Nitrate is a widespread contaminant in California groundwater. High levels of nitrate in groundwater are associated with agricultural activities, septic systems, confined animal facilities, landscape fertilization, and wastewater treatment facilities. Nitrate does occur naturally in groundwater – however, natural nitrate levels in groundwater are generally very low (typically less than about 10 mg/L as nitrate-NO3).

The volume-weighted average of existing TDS and nitrate-NO3 concentrations were calculated for each of the 22 analysis subregions. Results are summarized in Table 3-5.

Average subregional TDS concentrations vary considerably, ranging from 153 mg/L to 1,716 mg/L across the Region. Average TDS concentrations are very low in the upgradient portions of the Mojave River Basin (less than 300 mg/L) and increase along the pathways along and away from the Mojave River due to natural processes (e.g., mineralization) and impacts from anthropogenic loading. Eight of the nine downgradient analysis subregions composing the Alto Transition Zone, Centro, and Baja Subareas have average TDS concentrations at or above 500 mg/L (Baja - Floodplain is the lone exception). In the Morongo Basin, average TDS concentrations are generally below the recommended secondary MCL for TDS of 500 mg/L.

Exceptions include Lucerne Valley (north) (1,716 mg/L) and Johnson Valley (678 mg/L), where elevated TDS concentrations primarily reflect a high degree of mineralization and dry lakebed evaporation. Elevated TDS concentrations are naturally characteristic of dry lakes in arid desert environments.

Nitrate-NO3 concentrations are generally low across the Region. Average SNMP subregional concentrations are approximately 6.0 mg/L. Average nitrate-NO3 concentrations exceed 15 mg/L in Centro – Floodplain and Warren Valley. Additionally, nitrate-NO3 concentrations are slightly elevated (between 7.5 and 10 mg/L) in Centro – Regional (west), Alto Transition Zone – Floodplain (Helendale), and Alto – Right Regional. In the Centro Subarea, elevated nitrate concentrations are associated with historical and existing agricultural operations (crop field and dairies) and other naturally occurring processes. In the Alto subarea, septic tank return flows are likely the most significant contributing factor to slightly elevated groundwater nitrate concentrations. In the Warren Valley Basin, elevated nitrate concentrations are associated with historical entrainment of septage following managed aquifer recharge operations and a high density of septic tanks in the subarea. 428
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The emerging water quality constituents of concern are per-and polyfluoroalkyl substances (PFAS) and perfluorooctanoic acid (PFOA). These chemical constituents are generally produced through chemical manufacturing of items like Teflon pans, stain resistant carpet, and fast-food packaging. Acceptable levels for PFAS and PFOA compounds are regulated by the State of California and have recently been lowered. As such, the regulatory actions may have some impact on the regional availability of groundwater supplies. MWA and the regional purveyors are addressing this emerging issue in the region-wide management of groundwater resources and imported supplies that augment the local sources.

TABLE 3-5: AVERAGE EXISTING TDS AND NITRATE CONCENTRATIONS BY SNMP SUBREGION SNMP Analysis Subregion Average Existing TDS
Concentration (mg/L)
Average Existing Nitrate‐NO3
Concentration (mg/L)
Mojave River Basin
Baja ‐ Floodplain 401 3.9
Baja ‐ Regional 617 1.4
Centro ‐ Floodplain 711 20.7
Centro ‐ Regional (east) 618 3.2
Centro ‐ Regional (west) 711 7.7
Centro ‐ Regional (Harper Dry Lake) 1,028 4.0
Alto Transition Zone ‐ Floodplain
(Helendale) 915 10.0
Alto Transition Zone ‐ Floodplain 500 3.4
Alto Transition Zone ‐ Regional 529 3.9
Alto ‐ Floodplain (Narrows) 205 4.3
Alto ‐ Floodplain 177 3.3
Alto ‐ Left Regional 310 0.9
Alto ‐ Mid Regional 153 3.5
Alto ‐ Right Regional 579 7.5
Oeste ‐ Regional 781 2.5
Este ‐ Regional 299 4.3
Morongo Basin
Lucerne Valley (north) 1,716 5.6
Lucerne Valley (south) 472 5.7
Johnson Valley 678 6.2
Ames‐Means Valley 330 5.7
Warren Valley 243 15.4
Copper Mountain‐Giant Rock 247 7.5
Joshua Tree 202 14.7
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3.1.2.3 Groundwater Monitoring and Protection
The general goal of groundwater protection activities is to maintain the groundwater and the aquifer to ensure a reliable high quality water supply. Activities to meet this goal include continued and increased monitoring, data sharing, education and coordination with other agencies that have local or regional authority or programs. The current MWA groundwater monitoring program includes groundwater quality data collected by MWA and the USGS through their cooperative water resources program and through the Drinking Water Program directed by the State Water Resources Control Board Department of Drinking Water (SWRCB DDW).

The SWRCB DDW enforces the monitoring requirements established in Title 22 of the CCRs for drinking water wells and all the data collected must be reported to the DDW (note: each participating retailer’s specific Consumer Confidence Report is included within its respective Chapter). Title 22 also designates regulatory limits (e.g., MCLs) for various water contaminants, including volatile organic compounds, non-volatile synthetic organic compounds, inorganic chemicals, radionuclides, disinfection byproducts, general physical constituents, and other parameters. Title 22 testing applies to potable public drinking water systems. MWA performs Title 22 testing only on water produced for the R-Cubed distribution system which supplies wholesale potable water to a few retail water suppliers in the Alto Subarea.24 All retail water purveyors are subject to drinking water standards set by the Federal Environmental Protection Agency (EPA) and the SWRCB DDW.

MWA has developed and actively maintains a Key Well program to support ongoing groundwater management activities, including monitoring of groundwater levels and water quality throughout the Region. Wells in the Key Well program include a combination of dedicated monitoring wells, scientific investigation wells, domestic water supply wells, and agricultural irrigation wells. Retailer’s public water supply wells are not included in the Key Well program but data from these wells are tracked and included in the MWA database.

Important wells identified or installed during scientific studies are continually added to the Key Well program.

There are a range of groundwater contamination sites across the region. These sites are regulated by the Lahontan and Colorado River Basin Regional Water Quality Control Boards.

The potential detriments to water supply from these sites are being monitored by MWA and potentially effected retailers on a regional basis.
24 Groundwater quality data are submitted electronically and are available for download online at the SWRCB water quality analyses data and download page:
http://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/EDTlibrary.shtml 430
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3.1.3 Desalination Opportunities
The California UWMP Act requires a discussion of potential opportunities for use of desalinated water (Water Code Section 10631(i)). In the past, MWA has evaluated potential options for developing desalination projects. However, none of the opportunities are currently practical or economically feasible for MWA or the Mojave Region, and MWA has no current plans to pursue them. Therefore, desalinated supplies are not included in the supply summaries in this RUWMP.

As discussed elsewhere in this document, the groundwater supplies in the Region are not considered brackish in nature, and desalination is not required. There are brackish supplies near the dry lakes, but it is not practical to pump, treat and potentially induce migration of better-quality water to the dry lake areas. However, MWA and the retail water purveyors could partner with other SWP contractors and provide financial assistance in construction of other regional groundwater desalination facilities in exchange for SWP supplies. The desalinated water would be supplied to users in communities near the desalination plant, and a similar amount of SWP supplies would be exchanged and allocated to MWA from the SWP contractor for use in the Mojave Region. In addition, should an opportunity emerge with a local agency other than an SWP contractor, an exchange of SWP deliveries would most likely involve a third party, such as Metropolitan Water District. Most local groundwater desalination facilities would be projects implemented by retailers of SWP contractors and, if an exchange program were implemented, would involve coordination and wheeling of water through the contractor’s facilities to MWA.

Because the MWA service area is not in a coastal area, it is neither practical nor economically feasible for MWA to implement a seawater desalination program.

3.1.4 Delta Reliance
The Mojave Region continues to demonstrate reduced reliance on water supplies derived from the Delta and regional self-sufficiency through the actions of the retail agencies and MWA. The reduced reliance and regional self-sufficiency are attributable to significant advances in developing recycled and reusable water supplies combined with a region-wide emphasis on water use efficiency among MWA and the retail agencies. Table 3-6 presents the reduced reliance analysis for the Mojave Region. The Reduced Delta Reliance and improved regional self-sufficiency are detailed in Appendix 2. 431
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TABLE 3-6: REDUCED DELTA RELIANCE
Year 2010 2015 2020 2025 2030 2035 2040 2045 2050
Total Water Supplies from the
Delta Watershed 34.2% 34.2% 31.0% 26.1% 24.6% 23.5% 22.9% 22.3% 21.7% Change in Water Supplies from
the Delta Watershed -0.1% -3.3% -8.2% -9.6% -10.7% -11.4% -12.0% -12.5%

3.1.5 Climate Change
While the CWC does not prescribe specific climate change planning and management measures for water suppliers, it does emphasize that climate change is appropriate to consider when assessing drought risk assessment, water conservation and use efficiency, and demand management and supply – both in an historical and future – projection context.

The Region’s primary climate change concern involves MWA’s capability of providing imported SWP water for groundwater recharge and changes to the pattern and intensity of rainfall within the Region and snowfall in the mountains that feed the Mojave River and various local ephemeral streams.

As discussed in Chapter 6 – Mojave Water Agency, MWA uses DWR’s 2025 Delivery Capability Report (DCR) to assess current and future reliability of SWP Contract Table A supplies. MWA’s representation of supply availability during single dry and multiple dry years reflects its consideration of climate change impacts on its Table A water supplies.

3.1.6 Summary of Existing and Planned Water Supplies
Available wholesale water supplies in the RUWMP Planning Area consist of supplies managed exclusively by MWA and other supplies managed by constituent retail water agencies. MWA coordinates with its retailers to meet regional demands. Each retail water agency in the RUWMP Planning Area uses a unique mix of supplies and not all supply comes from MWA.

The projected total water supplies required to meet the demands of all of MWA’s retail agencies and other water uses within the Mojave Region are summarized below in Table 3-7 and Table 3-8. While MWA does not anticipate meeting all regional demands solely through collective water assets it directly manages, the Agency will work collaboratively with retail agencies and other stakeholders to manage available water supplies and ensure that projected regional demands can be met. The Region’s overall water asset portfolio consists of same-year SWP Table A allocations, Article 56 Carryover (and Article 21 Interruptible Water), Stored SWP supplies as managed by MWA, Water Transfers and Exchanges, local native groundwater, local surface water, return flows, and recycled supplies. 432
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TABLE 3-7: PROJECTED TOTAL WATER SUPPLY FOR THE MOJAVE REGION FOR THE NEXT 5-YEARS (AFY) Year Type
All Sources
(Native Groundwater, Recycled Water, SWP Table A)
Normal 162,812
Single Dry Year 118,810
Multi-Year Drought
2026 (1st Year) 145,759
2027 (2nd Year) 118,810
2028 (3rd Year) 118,810
2029 (4th Year) 132,280
2030 (5th Year) 145,759
TABLE 3-8: PROJECTED TOTAL WATER SUPPLY FOR THE MOJAVE REGION THROUGH 2050 (AFY) Year Type
All Sources
2030 2035 2040 2045 2050
Normal 162,812 164,046 164,642 165,216 165,716
Single Dry Year 118,810 120,044 120,640 121,214 121,714 Multi-Year Drought
Year 1 145,759 146,993 147,589 148,163 148,663
Year 2 118,810 120,044 120,640 121,214 121,714
Year 3 118,810 120,044 120,640 121,214 121,714
Year 4 132,280 133,514 134,110 134,684 135,184
Year 5 145,759 146,993 147,589 148,163 148,663
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Chapter 4.0 WATER USE

CHARACTERIZATION
Understanding water use characteristics across the Mojave Region is fundamental to evaluating long-term water supply reliability and informing regional water management strategies. As described in Chapter 2, the Region encompasses a diverse range of communities with varying population densities, land use patterns, and economic drivers, all of which influence water use behavior and demand. This chapter characterizes current water use across the region and develops projections of future water demand over the planning horizon.

Consistent with the coordinated regional approach established for the 2025 RUWMP, population, land use, and economic assumptions described in Chapter 2 form the basis for demand projections presented herein. Retailer-specific demand characteristics, including customer class distributions and system water use profiles, are developed within their respective retailer chapters and incorporated into the regional demand projections presented in this chapter. Demands occurring outside the service area boundaries of participating urban water retail suppliers – including agricultural, industrial, and recreational uses, as well as demands from small water systems and rural domestic pumpers – are characterized within the Mojave Water Agency’s wholesale planning framework as described in Chapter 6 – Mojave Water Agency.

Projected water demands developed in this chapter serve as the analytical framework for integrating regional water use with available supplies described in Chapter 3 – Water Supply Characterization. Together, these elements support the evaluation of system reliability under normal, single dry year, and multiple dry year conditions presented in Chapter 5 – Water System reliability and Drought Risk Assessment.

This chapter therefore provides a comprehensive and consistent framework for quantifying regional water use, supporting both near-term and long-term planning requirements and water resource management across the Mojave Region.

4.1.1 Current Regional Water Use
Water use within the Mojave Region reflects a diverse mix of urban, rural, industrial, recreational, and agricultural demands supported by a combination of managed 434
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groundwater and supplemental supplies. Understanding how water is currently used across the Region provides critical context for evaluating demand trends, informing future projections, and assessing long-term water supply reliability.

Water use within the Mojave Basin Area is tracked and reported through Mojave Watermaster Verified Production reports, which document production across the five Subareas in accordance with the terms of the adjudication. In addition, urban water suppliers track and report their production to the State Water Resources Control Board (SWRCB) through monthly reporting requirements. For areas outside of the Mojave Basin Area, such as Subregion 3, water use data for Hi-Desert Water District and Joshua Basin Water District is derived from agency production records and State Water Resources Control Board reporting. Historic demand data for other uses within Subregion 3, including smaller systems and non-urban demands, are based on estimates developed as part of MWA’s chapter, Chapter 6 – Mojave Water Agency.

Collectively, these data sources are synthesized to characterize recent and current water use across the Mojave Region. Table 4-1 presents a summary of regional water use for the period 2021 through 2025 by major use categories, including (1) urban water retail suppliers, (2) small potable water systems and rural domestic users, (3) other uses such as industrial, commercial, and recreational demands, and (4) agricultural uses. To further illustrate spatial variability in water use Table 4-2 through Table 4-4 provide a breakdown of these same categories by subregion.

This characterization of recent and current water use provides insight into regional demand patterns, the relative magnitude of different water use sectors, and the influence of long-term demand management measures and regulatory frameworks. These observed trends form the basis for developing and evaluating future water demand projections presented in the later portions of this chapter.
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TABLE 4-1: REGIONAL WATER USE 2021-2025 (AFY)
Water Use Category 2021 2022 2023 2024 2025
Urban Water Retail Supplier
City of Adelanto 4,487 4,640 4,570 4,636 5,044
County Service Area 64 2,793 2,677 2,561 2,597 2,666
County Service Area 70 J 1,794 1,725 1,633 1,146 1,742
Golden State Water Company - Barstow 6,004 5,604 5,421 5,591 5,437 Hesperia Water District 14,253 13,645 12,604 13,724 13,852 Hi-Desert Water Company 2,909 2,919 2,800 2,874 2,817
Joshua Basin Water District 1,333 1,299 1,276 1,307 1,292 Liberty Utilities - Apple Valley Water Company 10,014 9,538 9,399 9,698 9,642 Phelan Piñon Hills CSD 3,094 2,863 2,555 2,674 2,717
Victorville Water District 22,346 22,071 20,079 20,389 20,956 Subtotal Urban Water Retailer 69,028 66,981 62,897 64,636 66,164 Other
Small Water Systems and Rural Domestic 17,836 15,869 15,215 16,699 17,050 Industrial 10,435 10,135 9,035 9,235 7,335
Golf Course 4,615 4,715 3,515 4,415 5,215
Recreational 9,050 9,250 8,250 7,850 7,250
Agricultural 21,700 16,200 15,300 15,100 14,500
Subtotal Other 63,636 56,169 51,315 53,299 51,350
Total Water Use in Mojave Region 132,664 123,150 114,212 117,934 117,514 436
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TABLE 4-2: SUBREGION 1 WATER USE 2021-2025 (AFY)
Water Use Category 2021 2022 2023 2024 2025
Urban Water Retail Supplier
City of Adelanto 4,487 4,640 4,570 4,636 5,044
County Service Area 64 2,793 2,677 2,561 2,597 2,666
County Service Area 70 J 1,794 1,725 1,633 1,146 1,742
Hesperia Water District 14,253 13,645 12,604 13,724 13,852 Liberty Utilities - Apple Valley Water Company 10,014 9,538 9,399 9,698 9,642 Phelan Piñon Hills CSD 3,094 2,863 2,555 2,674 2,717
Victorville Water District 22,346 22,071 20,079 20,389 20,956 Subtotal Urban Water Retailer 58,781 57,159 53,400 54,864 56,619 Other
Small Water Systems and Rural Domestic 12,243 10,893 10,444 11,463 11,704 Industrial 5,600 5,100 4,900 5,500 4,400
Golf Course 4,400 4,500 3,300 4,200 5,000
Recreational 7,000 7,400 6,400 6,000 5,400
Agricultural 4,700 3,800 3,400 3,400 3,000
Subtotal Other 33,943 31,693 28,444 30,563 29,504
Total Water Use in Subregion 1 92,724 88,852 81,844 85,427 86,122 437
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TABLE 4-3: SUBREGION 2 WATER USE 2021-2025
Water Use Category 2021 2022 2023 2024 2025
Retailer
Golden State Water Company - Barstow 6,004 5,604 5,421 5,591 5,437 Subtotal Urban Water Retailer 6,004 5,604 5,421 5,591 5,437 Other
Small Water Systems and Rural Domestic 2,971 2,644 2,535 2,782 2,840 Industrial 4,500 4,700 3,800 3,400 2,600
Golf Course 0 0 0 0 0
Recreational 2,000 1,800 1,800 1,800 1,800
Agricultural 17,000 12,400 11,900 11,700 11,500
Subtotal Other 26,471 21,544 20,035 19,682 18,740
Total Water Use in Subregion 2 32,476 27,148 25,456 25,273 24,178 TABLE 4-4: SUBREGION 3 WATER USE 2021-202525
Water Use Category 2021 2022 2023 2024 2025
Retailer
Hi-Desert Water Company 2,909 2,919 2,800 2,874 2,817
Joshua Basin Water District 1,333 1,299 1,276 1,307 1,292 Subtotal Urban Water Retailer 4,243 4,218 4,076 4,180 4,109 Other
Small Water Systems and Rural Domestic 2,621 2,332 2,236 2,454 2,506 Industrial 335 335 335 335 335
Golf Course 215 215 215 215 215
Recreational 50 50 50 50 50
Agricultural 0 0 0 0 0
Subtotal Other 3,221 2,932 2,836 3,054 3,106
Total Water Use Subregion 3 7,464 7,150 6,912 7,234 7,214 25 Subregion 3 “Other” water use categories were estimated by Zanjero using available spatial and water-use indicators as no single Watermaster or centralized reporting source tracks all non-urban retail water use throughout Subregion 3.
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4.1.2 Forecasting Regional Water Use
Forecasting water use leverages the current understanding of prevailing regional water needs and trends while considering factors directly influencing more recent urban water use efficiency regulatory pressures and regional population trends. The following discusses the assumptions used to forecast water use at both the regional and subregional levels.

4.1.2.1 Forecasting Urban Water Retail Supplier Use
There are several factors significantly impacting the projection of future water use for the urban water retail suppliers ultimately informing the majority of the water use within the Mojave Region. These factors include State and local landscape regulations, building code requirements, and residential water-use mandates, as well as changes in types of housing products offered. These factors are incorporated into determining appropriate per-customer connection water demand values for use in forecasting future water needs. Relevant factors include:
• California Model Water Efficient Landscape Ordinance26 • Green Building Standards Code (hereafter the “CAL Green Code)27 • Per-capita Urban Water Conservation Objectives28
A significant portion of the projected growth in water demand includes a range of residential and non-residential uses within the urban water retail supplier’s service areas, driven by the varied development proposals already approved (but not yet built) as well as future proposals, to meet regional population increases. Residential customers will include both single-family dwelling units, some with accessory dwelling units, built under a variety of densities, as well as multi-family residential dwelling units. Non-residential uses are expected to include a blend of commercial, institutional, industrial, and active landscapes such as parks, in ratios similar to current residential-to-non-residential connections. The forecasted future demands of the 10 RUWMP urban water retail suppliers will reflect the needs of existing customers and future new customers. The methodology repeats that used for the 2020 Mojave Water Agency UWMP, where existing customer use and forecasted new customer use are primarily based upon multiplying the population by a gallons-per-capita-per day water factor for residential and non-residential uses.
26 Information regarding the California Model Water Efficient Landscape Ordinance (MWELO) can be accessed here.
27 Information regarding the Green Building Standards Code (CAL Green Code) can be accessed here. 28 Information regarding Per-capita Urban Water Conservation Objectives can be accessed here. 439
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Forecasting Existing Customer Future Use
For each urban water retail supplier, data submitted to the SWRCB to satisfy monthly reporting requirements was obtained to establish the current water use characteristics, as presented in Table 4-1. The current total annual production values were then divided by each retailer’s current population to generate gallons-per-capita-per-day (gpcd) values which are representative of each retailer’s total gpcd when considering all residential and nonresidential uses. The “current” gpcd values for these populations were then used to generate representative gpcd values for new customers as discussed below.

For existing customers’ future use, the gpcd was either (1) held constant or (2) reduced slightly to reflect expected conservation through replacement of fixtures and appliances, continued adoption of a conservation ethic, and modifications of irrigated landscapes, as well as a function of continued implementation of the retailer’s ongoing conservation programs.

Forecasting New Customer Future Use
One element of the information reported to SWRCB is the percentage each retailer serves to residential customers, a key value for the SWRCB’s determination of the “residential gallonsper-capita-per-day” water use – or “r-gpcd.” Using the total r-gpcd value as well as the wintertime r-gpcd values, which are often lower than during summer months, an estimate of the (1) residential versus non-residential per-capita use and (2) the residential indoor versus outdoor per-capita water use factor was derived for each retail supplier. The estimated gpcd values were then used to establish an anticipated gpcd value for each new customer using the following criteria:
• As stipulated by the CWC, each new residential user should have an indoor factor of 47 gpcd, dropping to 42 gpcd in the future.29 For purposes of this forecast, 47 gpcd is used for all new customers until 2030 and 42 gpcd is used for growth beyond 2030. • Using the residential indoor versus outdoor gpcd estimate from the existing customer data, an outdoor gpcd value was determined (as the difference between total r-gpcd and the estimated indoor r-gpcd). This outdoor value was added to the indoor value of 47 gpcd or 42 gpcd to generate a total residential gpcd value for future customers. • The difference between the residential gpcd and the total gpcd created a representative non-residential gpcd value unique to each retailer. This non-residential 29 CWC Section 10609.4(a)(2) establishes the indoor residential water use ‘standard’ to be 47 gpcd beginning in 2025 through January 1, 2030 while CWC Section 10609.4(a)(3) establishes the indoor residential water use ‘standard’ to be 42 gpcd beginning in 2030. These values represent average values across the entire customer base served by any urban water supplier. 440
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gpcd was added to the residential gpcd to create an expected total gpcd for each new customer.
• The new gpcd value was multiplied by the incremental additional population anticipated during each five-year increment through 2050. • The existing customer future demand and the new future customer demand were combined to represent the total demand for each large water retail supplier.

Projected water use for each participating urban water retail supplier is presented in the Water Use Characterization sub-chapter of each respective retailer chapter (Chapters 7 – 16). Each sub-chapter describes the retail-specific assumptions, customer use trends, existing and new customer demand forecasts, distribution system losses, and other factors used to develop each retailer’s projected water use. The regional demand summaries presented in this chapter rely on those retail-specific forecasts and aggregate them, where appropriate, to support the broader regional water use characterization and reliability analysis.

4.1.2.2 Forecasting Non-Urban Water Retail Supplier Uses In addition to the demands associated with participating urban water retail suppliers, the Mojave Region includes other water uses such as agricultural, industrial, golf, recreational, small systems, rural domestic, and other non-retailer demands. Historical use associated with these categories is summarized in this chapter to provide a more complete accounting of regional water use.

Future demands for non-urban water retail supplier uses were developed separately from the participating retailer demand projections. The methodology and assumptions used to forecast these demands are described in Chapter 6 – Mojave Water Agency. The regional demand projections presented later in this chapter aggregate these retailer and non-retailer forecasts to provide a total regional demand forecast for use in Chapter 5 – Regional Water Service Reliability.

4.1.3 Summary of Future Regional Water Use
The preceding sections identify the forecast sources used to develop future water use projections for the Mojave Region, including participating urban retail water supplier demands and non-urban/non-retailer demands. For regional planning purposes, these forecasts are aggregated in this section to present total projected water use for the Mojave Region.

Table 4-5 through Table 4-7 summarize projected water use from 2030 through 2050 by subregion. Table 4-8 summarizes projected regional water use from 2030 through 2050 and provides the long-term regional demand forecast used to evaluate supply and demand conditions in Chapter 5 – Regional Water Service Reliability. 441
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The projections presented in Table 4-5 through Table 4-8 reflect baseline planning demands, do not include an additional adjustment for climate change, and are rounded to the nearest five acre-feet.

TABLE 4-5: PROJECTED SUBREGION 1 WATER DEMAND 2030-2050 (AFY) TABLE 4-6: PROJECTED SUBREGION 2 WATER DEMAND 2030-2050 (AFY) TABLE 4-7: PROJECTED SUBREGION 3 WATER DEMAND 2030-2050 (AFY) Subregion 1 2030 2035 2040 2045 2050
Year 1 89,700 91,070 92,150 93,155 93,530
Year 2 89,975 91,290 92,355 93,220 93,560
Year 3 90,250 91,500 92,545 93,305 93,585
Year 4 90,525 91,715 92,750 93,375 93,610
Year 5 90,795 91,930 92,950 93,450 93,635
Subregion 2 2030 2035 2040 2045 2050
Year 1 24,270 24,480 24,875 25,510 26,120
Year 2 24,315 24,560 25,000 25,630 26,270
Year 3 24,355 24,635 25,130 25,755 26,415
Year 4 24,395 24,715 25,255 25,875 26,565
Year 5 24,435 24,795 25,380 25,995 26,715
Subregion 3 2030 2035 2040 2045 2050
Year 1 7,280 7,290 7,245 7,175 6,985
Year 2 7,285 7,275 7,225 7,140 6,965
Year 3 7,280 7,270 7,210 7,100 6,955
Year 4 7,285 7,260 7,205 7,060 6,935
Year 5 7,285 7,250 7,190 7,025 6,920
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TABLE 4-8: PROJECTED REGIONAL WATER DEMAND 2030-2050 (AFY) Mojave Region 2030 2035 2040 2045 2050
Year 1 121,250 122,840 124,270 125,840 126,635
Year 2 121,575 123,125 124,580 125,990 126,795
Year 3 121,885 123,405 124,885 126,160 126,955
Year 4 122,205 123,690 125,210 126,310 127,110
Year 5 122,515 123,975 125,520 126,470 127,270
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Chapter 5.0 REGIONAL WATER SERVICE

RELIABILITY
This chapter outlines the Mojave Region’s general water system reliability findings as required under CWC §10635 and provides reliability information that the MWA and its constituent retail agencies may use in completing an annual supply and demand assessment under CWC §10632.1.

Assessing water service reliability is the fundamental purpose for MWA and the participating retail suppliers in preparing this 2025 RUWMP. Water service reliability reflects the Region’s ability to demonstrate that the regional water needs may be satisfied under projected hydrological and regulatory conditions. The Region’s 2025 RUWMP considers the reliability of meeting water demands by analyzing plausible hydrological variability, regulatory variability, climate conditions, and other factors that impact the regional water supplies. The reliability assessment looks beyond past experiences and considers what could be reasonably foreseen in the future in order to reflect potential water supply planning scenarios. This chapter synthesizes the details imbedded in Chapters 3 and 4, which each on their own reflect synthesis of Chapters 6 through 16, and provides a rational basis for future decisionmaking related to supply management, demand management, and project development.

This chapter presents two regional water reliability findings:30 • Five Year Drought Risk Assessment: the 2026 through 2030 Drought Risk Assessment (“DRA”) for the Mojave Region;
• Long-Term Service Reliability: the reliability findings for a Normal Year, Single Dry Year, and Five Consecutive Dry Years in five-year increments through 2050; In summary, regional water supplies are sufficient to meet regional water demands during normal, single dry, and five consecutive dry years through 2050. 30 These findings are also used by Mojave Water Agency to represent reliability for their “wholesale water supplier” responsibilities under the UWMPA.
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5.1.1 Mojave Region Five-Year Drought Risk
Assessment
The Region is characterized by a unique portfolio of water supplies and infrastructure components. As noted in Chapter 3 – Regional Water Supply Characterization and Chapter 6 – Mojave Water Agency, the regional supplies that are available include MWA’s SWP Table A Annual Amount, Native Groundwater, Imported Wastewater, Return Flows, Recycled Water and Stored and Carryover supplies (such as Article 56). These supplies are managed throughout each of the Subregions. For example, although MWA brings its annual SWP Table A allocation into its service area for delivery into the Subregions, it also may store some of its Table A allocation within the SWP system under the Carryover provisions in its SWP Contract or may store portions of the Table A allocation in regional groundwater basins for use in later years. As such, the annual management of the diverse water supply sources in the regional water supply portfolio forms the supply reliability assessment described in this Chapter.

The Region, as coordinated through MWA, the participating retailers and other users, manages its water supplies to address projected dry conditions. Specifically, MWA captures and stores surplus imported water in normal and wet years to use those water assets to meet regional demands in dry years. These strategic management actions stabilize annual fluctuations in supplies that may not meet regional demands under certain dry conditions. In other words, any surplus imported water supplies are captured and stored for future delivery to improve long-term supply reliability. As discussed in Chapter 6 – Mojave Water Agency, MWA has preemptively stored over 250,000 acre-feet of water to mitigate against dry conditions.

Table 5-1 below shows the Region’s Five-Year Drought Risk Assessment (DRA) which integrates all of the regional water supplies for 2026 through 2030 as described in Chapter 3 – Regional Water Supply Characterization and reflects the water uses described in Chapter 4 – Water Use Characterization. As presented in the table, the Region maintains surplus water assets in the first, fourth, and fifth years of a projected five-year dry period but also indicates how stored water supplies are required to meet demands in the second and third years of the projected dry year period.
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TABLE 5-1: MWA FIVE YEAR DROUGHT RISK ASSESSMENT (AFY)
2026 2027 2028 2029 2030
Supply 145,759 118,810 118,810 132,280 145,759
Demand 119,390 119,856 120,351 120,832 121,252
Difference 26,369 -1,046 -1,541 11,448 24,507
Use of Managed
Groundwater Storage
0 1,046 1,541 0 0
Revised Difference 0 0 0 0 0
The key takeaway is that MWA uses a portion of its stored water assets in the middle of a multi-year drought period to address deficits in the otherwise predictable water supplies (e.g. native groundwater, recycled water, and current-year SWP Table A). In shoulder years, where imported supplies in combination with other supplies exceed the demands, MWA has the option for excess water to be stored for future use as either carryover supply in the SWP system (e.g., San Luis Reservoir) or banked underground in local groundwater basins.

5.1.2 MWA Long-Term Service Reliability
The UWMPA directs urban water purveyors to analyze water supply reliability in normal, single dry, and five consecutive dry years over a 20-year planning horizon. The 2025 UWMP Guidebook recommends extending that period to 25 years to provide a guiding document for future land use and water supply planning through the next UWMP Cycle. The following subchapters describe the long-term water service reliability for the Region through 2050.

5.1.2.1 Normal and Single Dry Conditions 2030-2050
The Region’s long term service reliability is characterized in normal, single dry, and five consecutive dry years through 2050. The future water supplies in normal and single dry conditions depicted in this section reflect the same hydrological, regulatory, and institutional criteria associated with each water asset as described in Chapter 3 – Regional Water Supply Characterization. In normal years, for example, SWP supplies are generally constrained only by the projected Table A allocations derived from DWR’s DCR. Under the normal conditions, the same-year SWP Table A allocation, combined with other supplies, is adequate to fully meet demand without using any of the locally pre-stored Managed Groundwater. In dry years, additional hydrological, regulatory, and institutional issues may constrain the availability of water that reduce SWP supply availability based on reduced allocation percentages as noted in Chapter 3. In these years, Managed Groundwater Storage is available to address any shortfall forecast absent the stored groundwater. Additionally, other future water supplies, like return flow, tend to grow in annualized volumes as annualized 446
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demands grow in parallel. However, as described in Chapter 3, many of these other supplies are not reflected as an annually available predictable supply to allow this RUWMP to make a conservative estimate of reliability. This information is described in detail in Chapter 3 and is incorporated into the supply and demand tables presented below.

The Region’s future water demands in normal and single dry conditions through 2050 reflect the same considerations described in previous sections of this chapter. In both normal and dry conditions, demands tend to reflect anticipated uses based upon the climatological conditions in the Region. Future water demands are generally predicted to increase as land uses and populations grow within the Region. This information is detailed in Chapter 4 – Water Use Characterization and reflected in the values shown in the tables below. In normal years, the Region projects surplus water conditions, allowing MWA to recharge and store available supplies for future dry-year needs or coordinate with other SWP contractors to manage surplus supplies. The 2027 Master Plan, currently under development, is expected to reflect MWA’s continued efforts to establish an imported water policy that helps provide further clarity regarding decisions during such circumstances.

Table 5-2 shows the normal year and single dry-year supplies and demands from 2030 through 2050. The single-dry conditions reflect the use of Managed Groundwater Storage to meet forecast shortfalls (shown as a negative difference), where the volume of Managed Groundwater Storage is set to resolve any shortfall to zero.31 31 As described in Chapter 6, MWA currently has over 250,000 acre-feet of Managed Groundwater Storage throughout the three Subregions. This supply is also available to help retail suppliers meet demands during future periods where demands may exceed the supply shown in their retail chapters in interim years but fall within the total 2050 supply shown in this RUWMP. 447
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TABLE 5-2: NORMAL AND SINGLE DRY YEAR WATER SUPPLY AND DEMAND THROUGH 2050 (AFY) Normal Year 2030 2035 2040 2045 2050
Supply 162,812 164,046 164,642 165,216 165,716
Demand 121,250 122,840 124,270 125,840 126,635
Difference 41,562 41,206 40,372 39,376 39,081
Single Dry Year 2030 2035 2040 2045 2050
Supply 118,810 120,044 120,640 121,214 121,714
Demand 121,250 122,840 124,270 125,840 126,635
Difference -2,440 -2,796 -3,630 -4,626 -4,921
Use of Managed
Groundwater Storage 2,440 2,796 3,630 4,626 4,921
Revised Difference 0 0 0 0 0

5.1.2.2 MWA Five Consecutive Dry Years through 2050
The Region defines a drought condition lasting five consecutive years as one that constrains MWA from obtaining some of the water supplies within its water supply portfolio due to hydrological, regulatory, and institutional constraints. These conditions include more restrictive regulatory constraints that limit its Table A allocation but do not limit the availability of groundwater resources or wastewater imports. As more thoroughly described in Chapter 6 – Mojave Water Agency, the multiple dry years are assumed to use the following consecutive Table A allocations: 35%, 5%, 5%, 20%, 35%. These assumptions set forth the available same-year Table A supply that is added to the native groundwater and other local supplies, as summarized in Chapter 3 – Regional Water Supply Characterization.

The future dry year projections show the Region relying more on Managed Groundwater Storage as its population grows and water demands increase. Specifically, the Region continues to increase its use of MWA’s Managed Groundwater Storage supplies in years two and three of a five consecutive year drought through the entire planning horizon. This gradual decrease in supply availability and eventual reduction in Managed Groundwater Storage in years one, four, and five would also impact MWA’s ability to store surplus water in those years.

Accordingly, although MWA will have adequate water supplies to meet the regional demands for five consecutive dry years in 2050, the Region will be using more of MWA’s Managed Groundwater Storage supplies to handle those conditions. These issues are described in significant detail in Chapter 3 – Regional Water Supply Characterization and reflected in the 448
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monthly reliability table below. Table 5-3 presents the water supply and demand conditions for MWA’s service area in five consecutive dry years from 2030 through 2050.

TABLE 5-3: FIVE CONSECUTIVE DRY YEARS WATER SUPPLY AND DEMAND THROUGH 2050 (AFY) 2030 2035 2040 2045 2050
Year 1
Supply 145,759 146,993 147,589 148,163 148,663
Demand 121,250 122,840 124,270 125,840 126,635
Difference 24,509 24,153 23,319 22,323 22,028
Year 2
Supply 118,810 120,044 120,640 121,214 121,714
Demand 121,575 123,125 124,580 125,990 126,795
Difference -2,765 -3,081 -3,940 -4,776 -5,081
Use of Managed
Groundwater Storage 2,765 3,081 3,940 4,776 5,081
Revised Difference 0 0 0 0 0
Year 3
Supply 118,810 120,044 120,640 121,214 121,714
Demand 121,885 123,405 124,885 126,160 126,955
Difference -3,075 -3,361 -4,245 -4,946 -5,241
Use of Managed
Groundwater Storage 3,075 3,361 4,245 4,946 5,241
Revised Difference 0 0 0 0 0
Year 4
Supply 132,280 133,514 134,110 134,684 135,184
Demand 122,205 123,690 125,210 126,310 127,110
Difference 10,075 9,824 8,900 8,374 8,074
Year 5
Supply 145,759 146,993 147,589 148,163 148,663
Demand 122,515 123,975 125,520 126,470 127,270
Difference 23,244 23,018 22,069 21,693 21,393
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5.1.3 Water Supply Reliability Summary
The Mojave Region’s water supply portfolio is capable of meeting the water uses in Region in normal, single dry, and five consecutive dry years from 2025 through 2050. 450
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Chapter 6.0 MOJAVE WATER AGENCY
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TABLE OF CONTENTS
Sub-Chapter 6.1 – Introduction .........................................................................................................................6-6

6.1.1 Background and Purpose...................................................................................................................................................... 6-7

6.1.2 Basis for Plan Preparation ..................................................................................................................................................... 6-7

6.1.3 Coordination and Outreach ................................................................................................................................................6-8

6.1.4 RUWMP Adoption......................................................................................................................................................................... 6-9

6.1.5 Document Organization......................................................................................................................................................... 6-9 Sub-Chapter 6.2 – Water Service and System Description ........................................................................6-10

6.2.1 Service Area Climate................................................................................................................................................................6-11 Sub-Chapter 6.3 – Population, Land Use, Economy, and Demographics ................................................6-12

6.3.1 Small Water System and Rural Domestic User Population............................................................................6-12 Sub-Chapter 6.4 – Imported Water Supply and Reliability Characterization ........................................6-14

6.4.1 State Water Project...................................................................................................................................................................6-14

6.4.2 SWP Restrictions........................................................................................................................................................................ 6-20

6.4.3 Delta Conveyance Project..................................................................................................................................................6-22

6.4.4 Evaluating and Managing Supply Reliability Risks..............................................................................................6-22

6.4.5 Evaluating Future Risk Scenarios....................................................................................................................................6-23 Sub-Chapter 6.5 – Managed Groundwater Storage ...................................................................................6-25

6.5.1 Alto Subarea................................................................................................................................................................................ 6-25

6.5.2 Centro Subarea......................................................................................................................................................................... 6-25

6.5.3 Baja Subarea.............................................................................................................................................................................. 6-26

6.5.4 Este Subarea............................................................................................................................................................................... 6-26

6.5.5 Oeste Subarea........................................................................................................................................................................... 6-26

6.5.6 Morongo Basin........................................................................................................................................................................... 6-26

6.5.7 Summary of Managed Groundwater Storage by Subregion......................................................................6-27

6.5.8 Water Quality...............................................................................................................................................................................6-27

6.5.9 Recycled Water Supplies ......................................................................................................................................................6-31

6.5.10 Desalination Opportunities..................................................................................................................................................6-31

6.5.11 Water Transfers and Exchanges......................................................................................................................................6-31

6.5.12 Supply Summary........................................................................................................................................................................6-31 452
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6.5.13 Groundwater within the Remaining Areas of the Mojave Region............................................................ 6-33 Sub-Chapter 6.6 – Water Use Characterization...........................................................................................6-35

6.6.1 Forecasting Water Demands Outside Participating Retailer Service Areas..................................... 6-35 Sub-Chapter 6.7 – Water Conservation and Shortage Response ............................................................6-40

6.7.1 Demand Management Measures ..................................................................................................................................6-41

6.7.2 Foundational Demand Management Measures ..................................................................................................6-41

6.7.3 Water Shortage Contingency Plan............................................................................................................................... 6-43 Sub-Chapter 6.8 – Water System Reliability and Drought Risk Assessment.........................................6-46 Sub-Chapter 6.9 – Energy Intensity Analysis ...............................................................................................6-47 453
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LIST OF TABLES
Table 6-1: Public Water System Information......................................................................................................................................6-8 Table 6-2: Projected Small Water System and Rural Domestic User Population 2030-2050 ..........................6-13 Table 6-3: MWA’s Historic SWP Table A Allocations and Deliveries .................................................................................. 6-16 Table 6-4: SWP Allocation Compared to Actual Deliveries into MWA Service Area...............................................6-19 Table 6-5: MWA Water Supply Portfolio Summary ......................................................................................................................6-32 Table 6-6: MWA’s Projected SWP Supply for 2026 – 2030 (AFY).........................................................................................6-32 Table 6-7: MWA’s Projected SWP Supply Through 2050 (AFY) ............................................................................................ 6-33 Table 6-8: Projected Small Water System and Rural Domestic Demand 2030-2050 (AFY) ...........................6-37 Table 6-9: Projected Agricultural Demand 2030-2050 (AFY).............................................................................................. 6-38 Table 6-10: Projected Industrial, Recreational, and Golf Course Demand 2030-2050 (AFY).......................... 6-39 Table 6-11: Energy Intensity – Total Utility Approach for Month Year through Month Year.............................. 6-47 454
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LISTS OF FIGURES
Figure 6-1: Example Representation of MWA’s Annual Management of SWP Supplies...................................... 6-20 Figure 6-2: Check 66 Electrical Conductivity 2015-2025......................................................................................................... 6-28 Figure 6-3: Check 66 Water Temperature 2015-2025 .............................................................................................................. 6-29 Figure 6-4: Check 66 Water Turbidity 2015-2025......................................................................................................................... 6-29 Figure 6-5: Check 41 (Kern) pH Value (2015-2025) .................................................................................................................... 6-30 Figure 6-6: Pacheco Pumping Plant Fluorescence 2015-2025 ........................................................................................... 6-30 455
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Sub-Chapter 6.1 – Introduction
The Mojave Water Agency (MWA or Agency) was formed in 1960 as a special act district codified in Chapter 97 of the California Water Code (CWC) Appendix as the Mojave Water Agency Law (MWA Law).32 The MWA Law states that MWA was created, in part, “to do any and every act necessary to be done so that sufficient water may be available for any present or future beneficial use of the lands and inhabitants of the agency….”33 That statutory charge has long been shaped by the region’s fundamental water management challenge:
groundwater use in excess of natural replenishment. The aquifers in MWA’s service area have been in overdraft since the early 1950s, as residents and other water users have historically used more water than is naturally replaced by limited rainfall and surface flows from the Mojave River and its tributaries originating in the San Bernardino mountains to the south. The Mojave Basin Area (MBA) Adjudication further reaffirmed MWA’s role in managing local water supplies and tasked MWA with seeking and securing supplemental water supplies to help address groundwater overdraft and support the quality of life within its boundaries.

The MWA service area encompasses approximately 4,900 square miles of eastern San Bernardino County (County) and is concurrent with the Mojave Region (Region or RUWMP Planning Area) boundary as that is used for purposes of this 2025 RUWMP. Its service area is divided into eight Subareas, each one affiliated with a hydrological groundwater basin or boundary defined through adjudications or resulting from other practical basis (see Figure 2- 1).

As discussed in Chapter 3 – Regional Water Supply Characterization, water supply for the Region is sourced almost entirely from pumped groundwater. As a State Water Project (SWP) contractor and MBA Watermaster, MWA acts as a wholesale supplier to large and small retail water agencies as well as many other individual users and uses throughout its service area by importing water supplies and placing them into the various groundwater basins to support on-going groundwater basin health needs – whether stipulated by judgments or based upon pre-emptive and anticipatory actions – to support the Region’s reliance on pumped groundwater.
32 California Water Code Appendix, Mojave Water Agency Law, Section 97-1 et seq., 1960. 33 MWA Law Section 97-1.5, July 21, 1960
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6.1.1 Background and Purpose
The Agency has ensured compliance with the Urban Water Management Plan Act (UWMPA) requirements for urban water suppliers through its participation in the 2025 RUWMP and preparation of this wholesale-specific chapter.34 The UWMPA requires urban water suppliers to evaluate the adequacy of their water supplies to meet projected demands under average conditions, single dry years, and multiple dry year scenarios through a 20-year planning horizon. This chapter, in conjunction with critical Regional summary tables presented in Chapter 3, Chapter 4, and Chapter 5, presents MWA’s evaluation of these requirements and demonstrates its ability to meet anticipated water demands under near-term and long-term normal and drought conditions.

The 2025 RUWMP, together with this wholesale-specific chapter, updates MWA’s 2020 Wholesale Urban Water Management Plan (UWMP) and incorporates new data, analyses, and regulatory guidance issued since 2020 by the California Department of Water Resources (DWR) pursuant to the CWC. In addition to satisfying statutory requirements, the 2025 RUWMP serves as a comprehensive planning document describing existing and future water supplies, projected water demands, demand management progress, and actions necessary to maintain long-term supply reliability. The regional approach also documents cooperative efforts among participating agencies to efficiently manage shared resources and address future water needs across the RUWMP Planning Area.

6.1.2 Basis for Plan Preparation
With one exception, MWA does not operate as a Public Water System (PWS) as described in California Health and Safety Code Section 116275. Rather, it is solely classified as an Urban Water Supplier pursuant to CWC Section 10617, as it provides water for wholesale water supplies for municipal purposes to more than 3,000 service connections and supplies more than 3,000 acre-feet of water annually through the management of imported water supplies on behalf of the Region. These qualifications require the preparation and adoption of a UWMP every five years. Under CWC Section 10620 (d)(1), these requirements may be satisfied through participation in a RUWMP, which the MWA and the other Urban Water Suppliers within the RUWMP Planning Area have elected to prepare collaboratively.

The one exception of a PWS is MWA’s Regional Recharge and Recover Project (R-Cubed) which is a conjunctive use project that pumps a combination of participating retailers’ MBA Judgement FPA and MWA’s Managed Groundwater Storage within the Floodplain Aquifer along the Mojave River in Hesperia and southern Apple Valley (see Figure 2-9 and Figure 3-1).

When needed, MWA-owned production wells on both sides of the Mojave River, immediately 34 California Water Code Sections 10610 through 10657
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downstream of the recharge areas, can recover and deliver the FPA or stored water through pipelines directly to local retail suppliers. Details of the MWA’s PWS are provided in Table 6-1.

TABLE 6-1: PUBLIC WATER SYSTEM INFORMATION
Public Water System Number Public Water System Name Number of Municipal Connections CA3610129 Mojave Water Agency
(R-Cubed) 5

6.1.3 Coordination and Outreach
Preparation of the 2025 RUWMP involved coordination among the participating Urban Water Suppliers and MWA. This coordination ensured consistency in assumptions, methodologies and regional analyses. MWA actively participated in this collaborative process through technical meetings, data sharing, and review of draft materials addressing regional conditions as well as MWA- and retailer-specific operations, As required by the UWMPA, MWA coordinated with nearby agencies during development of this chapter to ensure consistency with related land use and water resource planning efforts, including City General Plans, Water Master Plans, and Specific Plans associated with anticipated development.

Consistent with CWC Section 10641, MWA encouraged active participation from a broad cross-section of the community representing diverse social, cultural, and economic interests within its service area during preparation of this chapter. Public notice of the plan’s availability and the scheduled public hearing was provided, and a public hearing was conducted prior to adoption to solicit input from customers, stakeholders, and interested parties.

Comprehensive documentation of the regional planning process, including interagency coordination, formal notifications provided in accordance with CWC Section 10621(b), stakeholder engagement, and outreach activities conducted on behalf of all participating agencies is provided in Sub-Chapter 1.1.3 Coordination and Outreach of Regional Chapter 1 - Introduction.

6.1.3.1 Water Supplier Information Exchange
Compliance with CWC Section 10631 is described in Sub-Chapter 1.1.3 Coordination and Outreach of Regional Chapter 1 – Introduction.
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6.1.4 RUWMP Adoption
The Agency held a public hearing regarding the 2025 RUWMP on June 11, 2026. Before the hearing, the Agency made a draft of the 2025 RUWMP available for public inspection at 13846 Conference Center Drive Apple Valley, CA 92307, and posted on MWA’s website. Pursuant to CWC Section 10642, general notice of the public hearing was provided through publication of the hearing date and time in the local press as required under the UWMPA.

The Agency’s elected body adopted this 2025 RUWMP on June 11, 2026. A copy of the 2025 RUWMP will be submitted to DWR, provided to the County and the California State Library, and posted onto MWA’s website.

MWA plans to submit all required documentation related to the UWMPA through the DWR submittal website soon after adoption, including the on-line submittal of information associated with the following DWR Excel workbooks:
“FINAL Submittal 2025 UWMP Tables – MWA – 06.01.2026.xls” “Appendix F 2025 Checklist – MWA – 06.01.2026.xls”

6.1.5 Document Organization
This chapter is organized as follows:
• Sub-Chapter 6.2 Water Service and System Description
• Sub-Chapter 6.3 Population, Land Use, Economy, and Demographics • Sub-Chapter 6.4 Imported Water Supply and Reliability Characterization • Sub-Chapter 6.5 Managed Groundwater Storage
• Sub-Chapter 6.6 Water Use Characterization
• Sub-Chapter 6.7 Water Conservation and Shortage Response • Sub-Chapter 6.8 Water System Reliability and Drought Risk Assessment • Sub-Chapter 6.9 Energy Intensity Analysis
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Sub-Chapter 6.2 – Water Service and
System Description
The Agency manages water supplies from the urban, rural, industrial, recreational, and agricultural users throughout its expansive service area, depicted in Figure 2-1, which covers large portions of eastern San Bernardino County and the California side of the Mojave Desert.

The Mojave River is central to MWA history and settlement in the region. The river is more of an ephemeral stream which derives its flow from drainage of 217 square miles of the northern slope of the San Bernardino Mountains. Early farmers aggressively planted the Victor Valley with fruit trees and crops, which by the 1950s created serious water overdraft. This overdraft led to a halt in development in the area. Legislation for the SWP passed in 1959 to begin work on the California Aqueduct, along with the Davis-Grunsky Act, which afforded regions the opportunity to form local water agencies. Soon after, in 1960, the Mojave Water Agency was formed.

MWA’s service area is divided into seven divisions, each one represented by a publicly elected board member who serves a four-year term. The MWA Board uses a committee format to inform decisions and receive recommendations for voting matters with each committee member serving a one-year term (or until a successor is appointed). These committees generally meet once a month and include: Legislative and Community Partners Committee; Planning, Resources, Engineering and Operations Committee; Personnel, Finance, Security and Technology Committee; Morongo Basin Pipeline Commission; Technical Advisory Committee; and Watermaster.

MWA’s Sphere of Influence (SOI) is generally contiguous with its service area; however, there are two areas within the SOI that are currently not in its service area. Golden State Water Company serves the Wrightwood community’s 2,700 customers on the southern boundary of the MWA SOI. The other area is near Grass Valley Creek, which is a tributary to the Mojave River. These two areas are at the base of the San Bernardino Mountains and are part of the headwaters that connect the drainage to the groundwater basins that are part of the MBA Adjudication. MWA, serving as the court appointed MBA Watermaster according to the MBA Judgment, coordinates with these entities within the SOI to ensure established water supplies into the subbasins are maintained. An overview of the MBA Judgment is described in Chapter 3 – Regional Water Supply Characterization.

As also described more thoroughly in Chapter 3, water supply for MWA’s service area is sourced almost entirely from pumped groundwater from the various basins, subbasins, and aquifers in the area. MWA’s role is to help manage the groundwater basins by importing and 460
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managing delivery of imported supplies. To help with this, two primary water delivery projects were developed to deliver much-needed supply to additional locations in MWA’s service area from the SWP. The Morongo Basin Pipeline (MBP), completed in 1995, provides imported water to the upper portions of Mojave River Basin and to the Morongo subarea. The Mojave River Pipeline, completed in 2006, provides critical recharge to lower portions of Mojave River Basin (e.g. Centro and Baja subareas) and, more recently, will provide supplies to the Regional Aquifer west of Victorville.

6.2.1 Service Area Climate
A thorough description of the Mojave Region’s climate and considerations of climate change are included in Chapter 2 – The Mojave Region. Since MWA’s service area is concurrent with the Region’s boundary, details in Chapter 2 sufficiently address this UWMPA requirement and no additional details are provided in this sub-chapter. 461
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Sub-Chapter 6.3 – Population, Land
Use, Economy, and Demographics
Service area population and land use projections are critical to developing a useful planning framework as population dynamics and growth are a primary influence on water use in the Mojave Region. These projections directly influence planning measures for system supply, delivery, infrastructure, and demand management. Because MWA’s service area is concurrent with the Mojave Region as defined for this 2025 RUWMP, the regional population, land use, economic, and demographic conditions applicable to MWA are described in Chapter 2 – The Mojave Region.

Accordingly, this sub-chapter does not repeat the full regional population and land use discussion provided in Chapter 2. Instead, it identifies the subset of the regional population that is directly relevant to MWA’s wholesale demand forecast: the small water system and rural domestic user population located outside the service area boundaries of the participating urban water retail suppliers. This population is summarized at the regional level in Table 2-8 and is further organized by RUWMP Subregion in Table 6-2 to support the water demand forecast presented in Sub-Chapter 6.6 – Water Use Characterization.

6.3.1 Small Water System and Rural Domestic User
Population
The MWA population presented in Table 2-8 represents the portion of the Mojave Region associated with small water systems and rural domestic users outside the service area boundaries of the participating urban water retail suppliers. While Table 2-8 summarizes this population at the regional level, the water demand forecast presented in Sub-Chapter 6.6 requires this population to be organized by RUWMP Subregion.

To support this subregional breakout, residential lands outside the service area boundaries of the participating urban water retail suppliers were identified using the SCAG HELPR 2.0 land use shapefile.35 Lands designated as Mixed Use Residential, Commercial and Mixed Use Residential, Mobile Home and Trailer Parks, Multi-Family Residential, Rural Residential, and Single-Family Residential were classified as residential for purposes of this analysis. These residential lands were then assigned to the appropriate RUWMP Subregion. 35 SCAG HELPR 2.0 shapefile accessed at: https://rdp.scag.ca.gov/helpr/?page=Main-Page 462
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The number of residential parcels within each Subregion was used to determine the proportional share of the total small water system and rural domestic user population presented in Table 2-8. This method allowed the regional population total to be distributed among Subregions in a manner that reflects the relative location of residential land uses outside the participating retailer service areas. The resulting population projections are presented in Table 6-2 and provide basis for the small water system and rural domestic demand forecast presented in Sub-Chapter 6.6.

TABLE 6-2: PROJECTED SMALL WATER SYSTEM AND RURAL DOMESTIC USER POPULATION 2030-2050 Subregion 2030 2035 2040 2045 2050
Subregion 1 57,994 57,080 54,852 52,328 46,747
Subregion 2 14,075 13,853 13,313 12,700 11,345
Subregion 3 12,415 12,220 11,743 11,202 10,007
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Sub-Chapter 6.4 – Imported Water
Supply and Reliability
Characterization
This sub-chapter describes MWA’s water supply sources. The description includes the historical sources available to MWA as well as projected water supply sources through 2050.36 MWA delivers imported surface water to recharge facilities and groundwater systems throughout its service area, where the water contributes to local aquifer replenishment and can subsequently be extracted by retail agencies and other water users.

MWA categorizes its supply sources in essentially two groupings. The first grouping includes supply sources that are generally available on an annual basis. These sources include MWA’s SWP supplies that are made available each year. Other sources may occasionally fall into this category but are not incorporated into this RUWMP. The second set of supply sources are those that MWA could make available in any given year but are generally not renewable in MWA’s supply portfolio once they are used. In other words, although they can be replaced, like a water savings account, they are not guaranteed to be replaced on an annual basis. MWA’s long-term water supply management actions focus on optimal utilization of its annually available supply sources and protection of its pre-stored supply sources to guard against extended drought conditions and catastrophic outage impacting water users in the Region.

This sub-chapter describes MWA’s water supply portfolio and develops a supply matrix that integrates the supply sources to reflect MWA’s operational objectives.

6.4.1 State Water Project
The SWP provides a primary water supply for MWA. The water supply is derived from a series of water rights and water contracts as well as pumping and conveyance structures that connect the SWP supplies to MWA’s delivery system as described in Chapter 2 – The Mojave Region. MWA became a State Water Project contractor in June 1963, entering into a water service contract with the California Department of Water Resources (DWR). 36 The UWMP Act mandates a 20-year planning horizon and the 2025 UWMP Guidebook recommends a 25 year planning horizon.
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6.4.1.1 SWP Table A Contract Amount
MWA’s SWP Contract amount (Table A) has gradually increased since the Agency started taking deliveries in 1972. Initially the maximum Table A amount was 8,400 acre-feet per year (AFY) escalating to 50,800 AFY by 1990. MWA participated in two notable Table A permanent transfers, one in 1997 with Kern County Water Agency that augmented MWA’s Table A by 25,000 AFY, and one in 2009 with Dudley Ridge Water District for 14,000 AFY that stepped up the Table A amount in three increments (7,000 AF in 2010, 3,000 AF in 2015, and the final 4,000 AF in 2020). MWA’s current maximum SWP Contract Table A is 89,800 AFY.

MWA’s SWP Contract has numerous components that allow MWA to administer and control the annually available SWP water supplies. MWA’s SWP Contract has six important provisions that characterize the available supplies and the water delivery activities. The key aspects are:
(1) Annual Table A Amount, (2) Annual Table A Allocation, (3) Article 56 Carryover, (4) Article 21 Surplus Supplies, (5) Article 12(f) on SWP conveyance priorities, and (6) water transfer and exchanges supported by Amendment No. 17, the “Water Management Tools”.

As mentioned previously, MWA's Annual Table A Amount is 89,800 AFY, representing the maximum Table A amount available to the Agency under its SWP Contract. Although MWA’s SWP Contract provides for the Annual Table A Amount, that total volume of water supply is subject to reduction each year based on actual water supply availability in the SWP system as determined by DWR. The last 100% allocation year occurred in 2023. However, actual deliveries vary widely with significantly reduced percentages of maximum contract amount being available during drought years. The long-term average annual Table A Allocation provided by DWR’s 2025 Delivery Capability Report (DCR) is 54%.37 Since 2005 the DCR’s estimated average of total annual Table A water deliveries has decreased from 2,828 thousand acre-feet (TAF) to 2,234 TAF. This is based on several factors of note, including hydrology,38 infrastructure issues through the system, Delta regulations which constrained exports, and updates to the CalSim3 model. As such, the estimated long-term average annual Table A deliveries were adjusted down from 57% of maximum in 2021, to the Final DCR 2025 long-term average estimate of 54% under existing climate conditions. 37 The DWR 2025 Delivery Capability Report uses a hydrological modeling simulation to determine estimated deliveries under existing conditions using a historical time period from 1922-2021. Future delivery capability conditions are also modeled using these simulations along with CalSim3 and multiple climate change scenarios and future SWP system performance “levels of concern”. Projections of future delivery capability are not part of this analysis.
38 The 2025 DCR adjusted its hydrological baseline that incorporates statistically significant changes rim inflow from the rim watersheds into California’s Central Valley in which standard deviations of precipitation and runoff during the early periods of the past 100 years are significantly different from the recent 30 years due to climate change.
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As a point of reference, from 2010-2025, the average Table A Allocation for MWA was 39,218 AF (46% of max) in which allocations during that 15-year span ranged from 5% - 100%, as presented in Table 6-3. Average Table A Allocations over this period closely align with the 2025 DCR model projections for future conditions that incorporate climate change.39 It is important to note that extreme hydrologic variability may become more commonplace in future climate scenarios, and MWA could experience drastic variations in Table A Allocation and deliveries in the future.

TABLE 6-3: MWA’S HISTORIC SWP TABLE A ALLOCATIONS AND DELIVERIES Year MWA Contract Amount (AF) Table A Allocation Annual Allocation Amount (AF) 2010 82,800 50% 41,400
2011 82,800 80% 66,240
2012 82,800 65% 53,820
2013 82,800 35% 28,980
2014 82,800 5% 4,140
2015 82,800 20% 16,560
2016 85,800 60% 51,480
2017 85,800 85% 72,930
2018 85,800 35% 30,030
2019 85,800 75% 64,350
2020 89,800 20% 17,960
2021 89,800 5% 4,490
2022 89,800 5% 4,490
2023 89,800 100% 89,800
2024 89,800 40% 35,920
2025 89,800 50% 44,900
Average Allocation and Deliveries: 46% 39,218
39 Climate change effects modeled into the DCR delivery capability estimates include changes to monthly patterns of flows, more extreme hydrologic and drought events, and lower reservoir storage levels. Long-term average Table A delivery projections are estimated between 43-48% of maximum. (2025 DCR at Section 6, Table 6-2.)
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MWA's annual Table A allocation has specific utility to provide replacement water for the adjudicated basins and support sustainable groundwater management. The Morongo Basin Pipeline and Mojave River Pipeline, along with the Mojave River itself, deliver this imported water directly to dedicated recharge facilities throughout the various adjudicated subareas.

MWA utilizes SWP water primarily for groundwater recharge at these facilities, while maintaining over 250,000 acre-feet of stored water supplies both within local groundwater basins and as carryover storage in the SWP system to provide reliability during drought conditions and ensure long-term water security for the numerous retail water suppliers and end users within its service area.

6.4.1.2 Article 21
Article 21 of MWA’s SWP contract outlines the rules for “interruptible water service.” Interruptible water service means allocation of water that is essentially surplus in the SWP system and is in addition to the Table A Allocation in any given year. In other words, DWR may determine at a later date that there is additional water that could be delivered to requesting contractors that is in excess to that system-wide Table A Allocation. Article 21 was recently amended (Contract Amendment 17), and outlines the provisions for allocation, notice, and process for obtaining, rates, and transfers of Article 21 interruptible water. Notably, Amendment 17 allows for transfers of Article 21 water from certain SWP contractors to others if the contractor can demonstrate a special need for the transfer.

As a SWP Contractor, the Agency has access to Article 21 water when “excess” water is made available. Article 21 water is identified as non–Table A water that becomes available on an intermittent, interruptible basis. Allocations of Article 21 water are made based on the available supply in proportion to each contractor’s annual entitlement as set forth in its Table A for that year.

When available, Article 21 water delivery is typically made in the wettest months of the year, December through May. As such, Article 21 water is sometimes called “wet weather water”. It is offered to contractors when there is ample water in the system, and the State publishes a notice to contractors when it is made available. Article 21 water is not available for carryover storage in SWP facilities; however, a change in point of delivery is possible with a separate agreement with DWR in order to store Article 21 water outside of the service area. Notifications of Article 21 water availability come based on forecasting and existing hydrology, and the Article provides for the timely processing of requests by contractors for delivery. Demands are typically submitted for Article 21 water on a weekly basis.

The ability to take advantage of Article 21 water for MWA requires access to conveyance capacity in the aqueduct and available storage outside of San Luis Reservoir. Importantly, that priority for conveyance within the SWP goes to Table A water, and Article 21 water delivery may be interrupted if it is impacting a contractor’s Table A water delivery through a shared reach of the aqueduct. The Agency’s location on the East Branch of the aqueduct factors into the inherent conveyance priority limitations associated with Article 21 water. 467
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The 2025 SWP Delivery Capability Report indicates that Article 21 availability will be more frequent, especially in very wet years. Between 2000–2020, Article 21 water was available in all but two years; however, during multi-dry year stretches such as 2008-2010 and 2014–2016 the amount of Article 21 water available was orders of magnitude smaller than in normal to wet years. In summary, Article 21 water requires opportunistic operational flexibility for storage and conveyance capacity in the aqueduct to maximize its intermittent availability. Because of this uncertainty, this RUWMP does not include Article 21 as a quantifiable part of MWA’s water supply. Rather, MWA will continue to be opportunistic and access this supply as may best serve longer-term imported water policy objectives and groundwater basin needs.

6.4.1.3 Article 56 Carryover
Article 56 of MWA’s SWP Contract outlines the rules for storing unused Table A Allocation in any year for use in a subsequent year. The Article 56 Carryover water is stored in San Luis Reservoir. There are limitations to the total carryover amounts, subject to a percentage of the Annual Table A Amount, dependent on the final allocation percentage for that year. For example, if the final Table A Allocation was 50% (44,900 AF), MWA could store (carryover) 25% of its Table A Amount (22,450 AF). If storage requests exceed capacity in San Luis Reservoir, the available capacity will be allocated among contractors in proportion to their Table A entitlement. Reallocation can also result in “displacement” of stored water, sometimes known as “spill” that results in stored amounts being released.

Storing water in San Luis Reservoir for multiple years is allowed but comes with risk because of the potential of losing the stored water due to capacity restraints. Nevertheless, storage of SWP water in San Luis Reservoir under Article 56 is a critical component of MWA’s water asset management portfolio because it is a south of Delta storage option that allows carryover in multiple years. As an example of how this supply is managed, MWA had about 20,400 acrefeet of Article 56 supply available coming into the 2025 delivery year.

Due to the circumstances and water management choices made by MWA in 2025, a small amount of the available Table A supply was added to the carryover, resulting in the end-ofyear 2025 Article 56 total being slightly over 21,000 acre-feet. Due to hydrologic and operational conditions in early 2026, a portion of this carryover supply was at risk of spilling.

MWA anticipates that carryover storage by the end of 2026 will be slightly more than 12,500 acre-feet. The difference is expected to be used as part of MWA’s broader imported water management strategy, including meeting regional needs in 2026, potentially increasing storage in local subareas, and supporting transfers to other SWP contractors.

Although MWA may use its carryover supplies under normal year conditions, it generally preserves these supplies to manage shortage conditions derived from extended drought or catastrophic water outages.
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6.4.1.4 Summary of Historic SWP Deliveries
Collectively, MWA manages its SWP water supplies based on a variety of conditions, with each year reflecting a slight variance in both allocations, deliveries into the Region, and storage or sales to other parties. Table 6-4 shows this variance between 2010 and 2025 while Figure 6-1 provides a useful representation of how MWA evaluates and tracks its available SWP supplies year-over-year.

TABLE 6-4: SWP ALLOCATION COMPARED TO ACTUAL DELIVERIES INTO MWA SERVICE AREA Year Allocation Table A Amount (AF) Actual Deliveries (AF) 2010 50% 44,900 35,566
2011 80% 71,840 48,775
2012 65% 58,370 26,175
2013 35% 31,430 7,398
2014 5% 4,490 3,595
2015 20% 17,960 8,909
2016 60% 53,880 23,574
2017 85% 76,330 34,750
2018 35% 31,430 5,869
2019 75% 67,350 21,824
2020 20% 17,960 3,379
2021 5% 4,490 2,306
2022 5% 4,490 4,536
2023 100% 89,800 99,471*
2024 40% 35,920 2,618
2025 50% 44,900 19,220
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FIGURE 6-1: EXAMPLE REPRESENTATION OF MWA’S ANNUAL MANAGEMENT OF SWP SUPPLIES

6.4.2 SWP Restrictions
Neither DWR nor the SWP guarantees delivery of 100% of water allocations every year. Under the historic lowest 5% of allocations, SWP deliveries to MWA were 4,490 AF for the year. This, in conjunction with the expected decrease in reliability of the SWP over time, places a significant constraint on the reliability of SWP supplies as a source of imported water for recharge of the Region’s managed groundwater supplies. In addition to SWP system conveyance capacity limitations, MWA’s SWP supplies are also subject to notable policy and regulatory constraints.

6.4.2.1 The Delta Reform Act
The Delta Reform Act (DRA) of 2009 established the Delta Plan and the Delta Stewardship Council.
40 Ultimately, the DRA requires water purveyors to reduce reliance on water supplies derived from the Sacramento-San Joaquin Delta and improve reliance on locally developed water sources (see this RUWMP’s representation of compliance in Chapter 3 – Regional Water Supply Characterization). The Delta Plan is the governing document that guides the Delta’s future and spawned the DRA regional self-reliance policies. The Delta Plan has two “co-equal goals:” (1) providing a more reliable water supply for California; and (2) protecting, restoring, and enhancing the Delta ecosystem.
40 California Water Code Section 85225
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Specifically, urban water purveyors should demonstrate consistency with Delta Plan Policy WR P1 – Reduce Reliance on the Delta Through Improved Regional Water Self-Reliance (WR P1).41 WR P1 subsection (a) states that:

Water shall not be exported from, transferred through, or used in the Delta if all of the following apply:
1) One or more water suppliers that would receive water as a result of the export, transfer, or use have failed to adequately contribute to reduced reliance on the Delta and improved regional self-reliance consistent with all of the requirements listed in paragraph (1) of subsection (c);
2) That failure has significantly caused the need for the export, transfer, or use; and 3) The export, transfer, or use would have a significant adverse environmental impact in the Delta.

The DRA is relevant to MWA’s water asset portfolio and the water asset portfolios of its retailers because the DRA’s rules require reduced reliance on water supplies derived from the Delta in favor of locally developed water supplies. The methodology needed to comply with DRA’s regulatory requirement as noted in the policy is a reduction in “the percentage of water used from the Delta watershed.”

6.4.2.2 Healthy Rivers and Landscapes
The Bay Delta Plan's Healthy Rivers and Landscapes program, implemented through Voluntary Agreements (VAs), establishes specific "forgone export" requirements that would directly restrict SWP deliveries to south-of-delta contractors. Under these agreements, DWR and the Bureau of Reclamation must reduce exports from key Delta pumping facilities (Jones Pumping Plant and Clifton Court Forebay) based on water year types. The required export reductions range from zero in critical and wet years to 125,000 acre-feet in dry and below normal years, and up to 175,000 acre-feet in above normal years. These forgone exports are designed to ensure that additional upstream flows provided under the VAs actually reach the Delta as outflow rather than being captured by the export facilities.

The restriction mechanism works by establishing "reference conditions" representing pre-VA baseline operations, then requiring that SWP and Central Valley Project operations avoid exporting both these reference flows and the new additive VA flows. This creates a complex accounting system where south-of-delta water contractors would experience reduced deliveries not only from the direct export limitations, but also from the operational constraints needed to ensure VA tributary flows bypass the pumps and contribute to Delta outflow. The 41 Cal. Code Regs., tit. 23 Section 5003.
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program includes detailed daily and monthly tracking requirements to verify that the projects are indeed forgoing exports rather than simply capturing the additional upstream flows, effectively prioritizing ecosystem benefits over south-of-delta water supply reliability.

6.4.3 Delta Conveyance Project
The Delta Conveyance Project (DCP) is a proposed project by DWR to mitigate lost supply to the SWP associated with transporting water through the Sacramento-San Joaquin Delta (Delta). SWP contractors situated south of the Delta are exposed to multiple risk scenarios for long-term SWP supplies, including previously discussed regulatory compliance statutes.

Additional mitigation against other water supply risks driven by rising sea levels, earthquakes, progressive risk of levee failures, and extreme drought and flood are also identified as DCP benefits. Continuation of existing operation of the Delta is expected to increasingly expose water users that depend on water exported from the Delta to risks of interrupted water supply and decreasing water supply reliability over time. In short, the DCP is a significant risk mitigation component to help overcome uncertainties associated with conveying SWP water through the Delta.

MWA is an investor and participant in the DCP. The investment costs associated with MWA’s role are to fund the work plan and reserve capacity space in the project. The DCP does not increase water rights associated with the SWP but rather would restore losses caused by current physical and regulatory issues and mitigate against future changed conditions affecting SWP exports by adding a new point of diversion in the northern Delta. The Final Environmental Impact Report for the DCP was certified by DWR in December 2023 and a Change in Point of Diversion Petition was filed with State Water Resources Control Board (SWRCB) February 22, 2024. MWA’s participation in the DCP is safeguard for long-term supply reliability for the Region and its critical imported water supply.

6.4.4 Evaluating and Managing Supply Reliability Risks
MWA's water supply reliability is anchored by a diverse portfolio that includes SWP allocations, natural and managed groundwater, imported wastewater, return flows, and strategically stored water supplies totaling over 250,000 acre-feet. This diversity provides crucial flexibility in responding to varying hydrological and regulatory conditions, though it also introduces complex interdependencies that require sophisticated risk management approaches.

As both SWP contractor and MBA Watermaster, MWA must navigate the intersection of imported water reliability—in which average delivery projections have declined an estimated 22% over the last 20 years—with local groundwater management obligations under multiple court judgments. The Agency's stored SWP water assets serve as a critical buffer, enabling the system to maintain reliability even during extended drought periods when imported supplies may be curtailed.
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Still, MWA's water supply portfolio faces a range of threats that require comprehensive risk assessment and mitigation planning, including SWP operational and regulatory constraints, local infrastructure vulnerabilities, climate change-driven hydrological variability, extended drought scenarios, seismic risk, and other emerging challenges that could impact the Agency's ability to reliably meet regional water demands through the planning horizon.

6.4.5 Evaluating Future Risk Scenarios
MWA's reliability risk management operates within an increasingly complex regulatory environment, requiring coordination with Groundwater Sustainability Plans under the Sustainable Groundwater Management Act (SGMA), compliance with updated Urban Water Management Planning Act requirements, integration with local hazard mitigation planning, and compliance with statutes and authorities protecting federally endangered and threatened species under the Endangered Species Act (ESA), D-1641 Bay Delta Water Quality Control Plan, and California Endangered Species Act (CESA), among others.

Climate change introduces additional layers of complexity to traditional reliability planning.

Regional temperature data shows gradual warming trends over the past century, potentially increasing evapotranspiration rates and water demand pressures. While the high desert climate already experiences extreme conditions that limit the impact of incremental change, MWA recognizes the need to incorporate climate vulnerability assessment into long-term planning frameworks.

The significant risks to MWA’s water supplies mainly relate to sustained reductions in SWP deliveries. The SWP’s own climate adaptation planning, addressing more intense flood and drought cycles and rising sea levels in the Delta, directly impacts MWA's imported supply reliability. The DWR Delivery Capability Report, as discussed previously, indicates the expectation that the long-term average of the SWP deliveries will decrease. This trend of predicted long term average reductions has occurred in previous Delivery Capability Reports as well, and it is clear DWR plans to manage the SWP along these expectations. Even as projects like the Delta Conveyance Project are proposed to alleviate some of this supply reduction, it is only expected to mitigate reductions in supply rather than eliminate or even just stabilize the trend.

The most significant risk in the immediate future would be a sustained drought. If a multiyear severe drought were to impact SWP supplies and the MWA service area simultaneously, MWA would face a period with minimal capacity to recharge groundwater coupled with significant demand from within the service area that would strain basin health. Additionally, groundwater overdraft has led to ground subsidence along certain parts of SWP infrastructure, and while SMGA aims to mitigate subsidence and its impacts to the infrastructure, several groundwater basins across the State are still not in compliance and place the infrastructure at continued risk.
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Seismic risks must also be considered in water supply reliability planning. Earthquakes put SWP infrastructure at risk, including dams, pumping plants, aqueducts, tunnels, and pipelines, many of which are located in seismically active parts of the state. Cascading risk such as fire from broken gas or electrical lines and flood risk from damaged dams or levees are also of concern. For instance, a major earthquake in the Bay Area that caused levee failure in the Delta could cause a catastrophic outage of water deliveries that could last for months or longer while repairs were made and salinity levels were restored. Seismic risks to critical infrastructure and potential supply disruptions require seismic monitoring and preparedness, infrastructure improvements, and comprehensive emergency response planning and system hardening strategies.

Water supply infrastructure within the MWA service area also poses potential risks to water deliveries. Significant portions of MWA’s pipelines face corrosion challenges, and repairs or replacement could reduce service capacities and the ability to take SWP water deliveries for groundwater recharge. Capital improvement projects must also be aligned to prevent artificial constraints on MWA supplies. Additionally, certain assets face other technical or biological constraints, such as water imports that could impact the Arroyo Toad or debris in the California Aqueduct limiting the ability to take water. These are systemic issues that impact the reliability of MWA’s water supplies but are manageable with foresight and prioritized action.
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Sub-Chapter 6.5 – Managed
Groundwater Storage
As previously indicated, managed groundwater storage represents a critical component of water supply reliability across the Mojave Region, encompassing both the five MBA Judgment subareas and the Morongo Basin. MWA directly stores imported water in the MBA subareas, accounted for as “Managed Groundwater Storage,” and in the Morongo Basin under two separate agreements in the Ames Valley Basin and Warren Valley Basin.

Based on the most recent reporting, MWA maintains approximately 256,000 acre-feet of stored groundwater within the Mojave Basin Adjudication subareas, with an additional 173 acre-feet stored in the Morongo Basin under separate agreements.42

6.5.1 Alto Subarea
The Alto Subarea storage account balance is approximately 194,000 acre-feet. The Alto Subarea above the Lower Narrows continues to serve as the largest repository of MWA's stored groundwater. Operating parameters have been established with a minimum operating level based on 2016 storage conditions and a maximum level representing eight years of average annual consumptive use (approximately 55,000 acre-feet). Since 1996, the subarea has experienced significant storage depletion, with a cumulative change of -510,826 acre-feet through 2024, though recent years showed recovery with a positive change of 35,963 acre-feet in Water Year 2023-2024. Water levels exhibit seasonal variation near the Mojave River, with declining trends in heavily pumped areas, particularly in the western portion of the Regional Aquifer.

6.5.2 Centro Subarea
The Centro Subarea storage account balance is approximately 35,000 acre-feet. The Centro Subarea operates under defined parameters established since 1997. The minimum operating range reflects the lowest storage since establishment of the Judgment when the basin was considered healthy, with maximum levels representing five years of average annual consumptive use (approximately 18,000 acre-feet). The subarea demonstrated positive storage recovery in Water Year 2023-2024 with a net gain of 29,794 acre-feet. 42 Planning, Resources, Engineering, and Operations Committee presentation, March 31, 2026. 475
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6.5.3 Baja Subarea
The Baja Subarea storage account balance is approximately 25,000 acre-feet. The Baja Subarea faces ongoing challenges, having lost approximately over 500,000 acre-feet of groundwater storage since 1996. However, recent trends suggest potential stabilization, with indications that continued pumping at current or lower levels due to reduced agricultural operations may halt continuous depletion. Optimal operating parameters remain under development.

6.5.4 Este Subarea
The Este Subarea storage account balance is approximately 1,300 acre-feet. The Este Subarea appears to maintain natural balance, with water supply and use remaining balanced over the past 20 years based on water level data. The subarea achieved equilibrium in Water Year 2023-2024 with no net change in storage. While optimal operating parameters have not been formally established, the long-term stability suggests sustainable management under current conditions. MWA has developed demonstration groundwater recharge facilities in the subarea and is continuing geotechnical investigations to support future recharge basin development.

6.5.5 Oeste Subarea
The Oeste Subarea currently maintains no MWA stored water accounts but demonstrates natural balance between water production, supply, and outflow. Water level data indicates short-term stability, leading to a "no change in storage" designation for planning purposes.

MWA has installed monitoring wells and approved design of a pilot recharge basin on a 10- acre Agency-owned parcel.43 Geotechnical investigations are also ongoing to identify optimal locations for future off-Mojave River recharge facilities.

6.5.6 Morongo Basin
Beyond the MBA subareas, MWA maintains strategic storage in the Morongo Basin through two separate agreements. Storage includes 173 acre-feet in the Ames-Reche Management Area but zero acre-feet in Joshua Basin. The Ames-Reche Agreement covers 95 square miles and involves multiple agencies including Bighorn Desert View Water Agency and Hi-Desert Water District. Since 2012, water levels across the Ames-Reche Management Area have remained relatively stable, with annual pumping around 1,200 acre-feet compared to the established baseline of 1,646 acre-feet per year. The Warren Valley Basin within the Morongo area benefits from imported water deliveries through the Morongo Basin Pipeline, supporting 43 MWA Watermaster 2023-2024 Supply Conditions Report at p. 16. 476
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both the Warren Valley Basin Judgment requirements and enhanced storage management.

Water levels have generally increased since implementation of recharge and management actions.

6.5.7 Summary of Managed Groundwater Storage by
Subregion
When organized into the three Subregions discussed in Chapter 2 – The Mojave Region, the Managed (Stored) Groundwater Storage is:
• Subregion 1: 194,000 AF (Alto) + 1,300 AF (Este) + 0 AF (Oeste) = 195,300 AF • Subregion 2: 35,000 AF (Centro) + 25,000 AF (Baja) = 60,000 AF • Subregion 3: 173 AF (Ames) = 173 AF
While no formal minimum storage target has been set by MWA, this supply is viewed as a vital contingency source for potential repeating instances of very low SWP Table A Allocations in consecutive years – or for other drivers impacting the current year’s SWP Table A availability. As such, this source is recognized as available to meet Subregional demands whenever native groundwater (e.g. FPA for parties subject to the MBA Judgment), local recycled supplies, and anticipated Table A supplies are insufficient.

This supply is also available to help retail suppliers meet demands during future periods where demand may exceed the supply shown in their retail chapters in interim years but fall within the total 2050 supply shown in this RUWMP. Overall, use of this supply is represented within this RUWMP by making these supplies available in forecast supply tables for multiple dry year supply reliability in any event where a shortfall in Table A, native groundwater, or recycled water is projected prior to the use of the managed storage (see Chapter 5 – Regional Water Service Reliability).

6.5.8 Water Quality
This subsection focuses on the quality of State Water Project supplies imported into the region and recharged into the various portions of the groundwater basins and adjudicated areas throughout the Mojave Region. A discussion of groundwater quality is included in Chapter 3 – Regional Water Supply Characterization.

The quality of imported surface water conveyed through the California Aqueduct is monitored by the DWR Division of Operations and Maintenance. DWR maintains 16 continuous water quality monitoring stations located throughout the SWP and data collected from these stations is regularly updated to the California Data Exchange Center (CDEC). The parameters for monitoring SWP water quality include electrical conductivity, water temperature, turbidity, pH, and fluorescence. SWP water quality changes as the water moves from precipitation and snowmelt runoff in Northern California to its termination points in Southern California. As such, 477
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the water quality measurements at each station are important for purposes of tracking water quality constituents in the SWP system.

Of the 16 water quality monitoring stations, Check 66 is located closest to MWA’s turnouts and Check 41 is examined to align operational decisions and data monitoring. Check 66 is located at an elevation of 3,448 feet in San Bernardino County near the City of Hesperia in the South Lahontan Hydrologic Region (see Figure 2-7). Figures 6-2 through 6-4 show the measured publicly available electrical conductivity, temperature, and turbidity at Check 66 since 2015 through 2025. Figure 6-5 shows pH at the Check 41 Kern measurement location and Figure 6-6 shows fluorescence at the Pacheco Pumping Plant.44
FIGURE 6-2: CHECK 66 ELECTRICAL CONDUCTIVITY 2015-2025
44 These varying water quality monitoring station locations were chosen because Check 66 does not collect these water quality parameters and the Kern location (Check 41) and Pacheco Pumping Plant monitoring stations were the nearest to Check 66.
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FIGURE 6-3: CHECK 66 WATER TEMPERATURE 2015-2025
FIGURE 6-4: CHECK 66 WATER TURBIDITY 2015-2025
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FIGURE 6-5: CHECK 41 (KERN) PH VALUE (2015-2025)
FIGURE 6-6: PACHECO PUMPING PLANT FLUORESCENCE 2015-2025 480
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6.5.9 Recycled Water Supplies
MWA is not directly involved with the creation or distribution of recycled water supplies. This activity does occur within a few of the retailer’s service areas, notably Hesperia Water District and the City of Victorville. MWA has zero recycled water supplies nor forecasts for such supplies.

6.5.10 Desalination Opportunities
The California UWMP Act requires a discussion of potential opportunities for use of desalinated water (Water Code Section 10631[i]). This discussion takes place in Section 3.1.3 of Chapter 3 – Regional Water Supply Characterization.

6.5.11 Water Transfers and Exchanges
MWA engages in water transfers and exchanges involving its SWP assets and other SWP Contractors’ SWP assets. Historically, MWA has both received and delivered water through these transfers and exchanges with various agencies throughout California. These transfers are essentially spot market transfers where short-term opportunities are identified and then actions taken for purchase and acquisition. These transfers help support management of MWA’s and its retail agencies’ water supply portfolios. Future MWA transfers and exchanges depend upon allocations available to MWA and other water purveyors and are not considered an available supply for purposes of this RUWMP.

6.5.12 Supply Summary
Mojave Water Agency operates a diverse and strategically managed water supply portfolio that serves over 500,000 residents across a 4,900-square-mile service area. As both a SWP contractor and MBA Watermaster, MWA's water supply strategy centers on importing surface water for groundwater recharge to support sustainable management of local groundwater basins.

MWA’s water supply portfolio consists of four primary components that work together to provide reliable water service through varying hydrological conditions. SWP imports form the foundation of MWA's supply strategy, with a maximum annual Table A contract amount of 89,800 acre-feet delivered through six turnout locations on the East Branch of the California Aqueduct. These imported supplies are primarily used for groundwater recharge rather than direct service delivery, supporting the adjudicated basin management framework that governs regional water use.

This integrated portfolio enables MWA to maintain water supply reliability across normal, single dry year, and multiple dry year conditions. The Agency's water supply diversification includes annual imported water deliveries combined with strategically managed locally 481
Mojave Water Agency Sub-Chapter 6.5 – Managed Groundwater Storage 2025 Mojave RUWMP – Public Draft 6-32
stored groundwater as well as SWP carryover supplies. A summary of MWA’s water supply portfolio is shown in Table 6-5.

TABLE 6-5: MWA WATER SUPPLY PORTFOLIO SUMMARY
Source Annual Amount Description
State Water Project – Table A 89,800
Maximum Table A contract amount;
actual deliveries vary (46% average
2010-2025)
SWP – Article 21 Variable Intermittent SWP surplus water when available
SWP – Article 56 Carryover Variable Stored SWP allocation in San Luis Reservoir
Managed Groundwater Storage 256,00045 Storage across Mojave Basin subareas and Morongo Basin
For purposes of this RUWMP, the forecast of MWA’s SWP supplies are presented in Table 6-6 and Table 6-7.

TABLE 6-6: MWA’S PROJECTED SWP SUPPLY FOR 2026 – 2030 (AFY) Year SWP Contract Table A Percent Allocation Allocation Amount Normal 89,800 54% 48,492
Single Dry 89,800 5% 4,490
Multi-Year
Drought
2026 (1st year) 89,800 35% 31,430
2027 (2nd year) 89,800 5% 4,490
2028 (3rd year) 89,800 5% 4,490
2029 (4th year) 89,800 20% 17,960
2030 (5th year) 89,800 35% 31,430
45 March 2026 State Water Project Allocation and Imported Water Operations Plan Update, Presentation on March 31, 2026 to the Planning, Resources, Engineering, and Operations Committee. 482
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TABLE 6-7: MWA’S PROJECTED SWP SUPPLY THROUGH 2050 (AFY) Total Supply Percent
Allocation 2030 2035 2040 2045 2050
Normal 54% 48,492 48,492 48,492 48,492 48,492
Single Dry Year 5% 4,490 4,490 4,490 4,490 4,490 Multi-Year Drought Year 1 35% 31,430 31,430 31,430 31,430 31,430
Year 2 5% 4,490 4,490 4,490 4,490 4,490
Year 3 5% 4,490 4,490 4,490 4,490 4,490
Year 4 20% 17,960 17,960 17,960 17,960 17,960
Year 5 35% 31,430 31,430 31,430 31,430 31,430
The characterizations of MWA’s SWP Table A Allocation long-term reliability reflect numerous hydrological and regulatory issues that inform the State’s DCR modeling, are reasonable assessments related to SWP system management, and reflect MWA’s local conditions. Longterm water management hydrological and regulatory issues include the Bay-Delta Water Quality Control Plan, the Coordinated Operations Agreement, the Delta Biological Opinion, the Delta Conveyance Project, modifications to San Luis Reservoir, SWP seismic considerations, DWR’s Emergency Planning, and assessments related to MWA’s local groundwater conditions and climate. MWA thoughtfully engages on all these issues and undertakes actions that help mitigate supply related impacts that may be caused by one or more listed items. These issues are all considered in MWA’s planning and incorporated into its supply characterizations in this RUWMP.

6.5.13 Groundwater within the Remaining Areas of the
Mojave Region
Besides its primary role as an importer of SWP supplies, MWA provides the geographic representation for the use of groundwater throughout the rest of the Region that is outside the service areas of the participating RUWMP retailers. The demand for water mostly reflects the other small retail water suppliers, rural domestic users, agricultural users, and large and small industries that are subject to the MBA Judgment.

Like to the other retail agencies, these users pump groundwater from the adjudicated MBA, specifically in Subregion 1 and Subregion 2 (see Figure 2-3). As discussed elsewhere, the basins used to meet these demands are recharged through several means, including natural recharge from the Mojave River, lateral subsurface groundwater movement from the adjacent San Gabriel mountains, imported water from the State Water Project (managed by MWA), and other sources like irrigation runoff, return flows from septic systems and water 483
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delivery systems, and treated wastewater effluent. A detailed description of the MBA, Subareas, aquifer characteristics, adjudication, management areas, and other adjudicated basins is presented in Chapter 2 – The Mojave Region.

6.5.13.1 Mojave Region’s Remaining Free Production
Allowance
Under the MBA Judgment, each producer is assigned a Free Production Allowance (FPA), representing the annual quantity of groundwater that may be extracted without replacement obligations. The FPA for each participating retail water supplier is discussed and quantified for near- and long-term forecasts in each of their respective Chapters. For the remaining areas of the Mojave Region not part of the retail service areas, particularly in Subregion 1 and Subregion 2, there is a cumulative FPA that represents the near- and long-term FPA available to meet all these other users and uses. This groundwater is not controlled directly by MWA as a water supply but is managed through MWA’s role as the MBA Watermaster and represented in determinations of Base FPA.

For purposes of fully representing available FPA, this subchapter uses recent FPA quantities as they are presented by the MBA Watermaster in recent reports. Specifically, the forecast availability of native groundwater is determined by removing the retailer-specific FPA from the MBA Watermaster report for Base FPA.46 This value, along with the representation of MWA’s imported supply, is reflected in the water supply summary tables presented in Chapter 3 – Regional Water Supply Characterization.
• Subregion 1 – Total annual Base FPA is approximately 70,400 acre-feet. Total RUWMP Retailer FPA is approximately 38,000 acre-feet. Remaining Base FPA is approximately 32,300 acre-feet.
• Subregion 2 – Total annual Base FPA is approximately 39,600 acre-feet. Total retailer FPA is approximately 8,050 acre-feet. Remaining Base FPA is approximately 31,500 acre-feet.
46 Water Year 2024-2025 Watermaster Report, Appendix B-Summary, p. 15 of 16. 484
Mojave Water Agency Sub-Chapter 6.6 – Water Use Characterization 2025 Mojave RUWMP – Public Draft 6-35
Sub-Chapter 6.6 – Water Use
Characterization
This sub-chapter describes the methodology used to forecast water demands within MWA’s service area that occur outside the service area boundaries of the ten participating urban water retail suppliers addressed in Chapters 7 through 16. These demands include small water systems, rural domestic users, agricultural uses, industrial uses, and golf course and recreational uses that are not otherwise quantified in the individual retailer chapters. Because MWA’s service area is concurrent with the Mojave Region, these demands are part of the overall regional water use forecast and are necessary to evaluate MWA’s wholesale water supply planning responsibilities.

Current regional water use, including use by participating urban water retail suppliers and other water users within the Mojave Region, is summarized in Section 4.4.1 – Current Regional Water Use of Chapter 4 – Water Use Characterization. Section 4.4.1 presents recent water use by major category and subregion and provides the current-use accounting used for the regional demand analysis. To avoid duplicating these tables and descriptions, this subchapter focuses on the methodology used to project future demands for small water systems and rural domestic users, industrial uses, golf course, recreational uses, and agricultural uses outside the service areas of the participating RUWMP retailers.

The resulting forecasts are incorporated into the regional demand summaries presented in Chapter 4 – Water Use Characterization and carried forward into Chapter 5 – Regional Water Service Reliability. Accordingly, this sub-chapter does not repeat the regional demand totals presented in Chapter 4 or the retailer-specific forecasts presented in Chapters 7 through 16.

Instead, it presents the other-use demand forecasts developed for MWA’s wholesale planning purposes and documents the assumptions, data sources, and methods used to develop those values. When combined with the applicable retailer forecasts, these other-use demands form the basis for the Subregion and Regional demand totals summarized in Tables 4-5 through 4-8.

6.6.1 Forecasting Water Demands Outside Participating
Retailer Service Areas
Small retail water supplier and rural domestic uses, agricultural uses, industrial uses, recreational uses, and golf course uses were forecast separately from the demands developed for the participating urban water retail suppliers. For the adjudicated portions of 485
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MWA’s service area, these categories are tracked and reported annually by the Mojave Watermaster by adjudicated subarea. The Watermaster-reported production data were used as the primary basis for characterizing historical use and developing future demand forecasts in Subregions 1 and 2.

The Morongo Subarea is not part of the MBA adjudication, and comparable Watermasterreported production data are not available for water uses outside of Hi-Desert Water District and Joshua Basin Water District. Accordingly, small retail water supplier and rural domestic, agricultural, industrial, recreational, and golf course demands outside of those retailer service areas were estimated using best available planning-level information, including available supplier data, land use and spatial information, and demand assumptions developed as part of MWA’s broader demand analysis.

6.6.1.1 Small Water Systems and Rural Domestic Use
MWA’s service area includes small public water systems and rural domestic users located outside the service area boundaries of the participating urban water retail suppliers. Chapter 2 – The Mojave Region presents the overall population associated with MWA’s wholesale demand area; however, this sub-chapter focuses on the methodology used to translate that population into projected water demands. For the adjudicated portions of MWA’s service area, small water system and rural domestic use is tracked through Mojave Watermaster reporting. Water use for small public water systems is generally metered and reported, while use by small private pumpers, which primarily reflects rural residential domestic use, is estimated by the Mojave Watermaster. These data were used to characterize recent historical use and develop a representative per-capita demand factor.

Future demand for this user class within Subregions 1 and 2 was estimated by dividing the reported total water use by the associated small water system and rural domestic population. In 2025, this user class within Subregions 1 and 2 had an estimated population of approximately 72,023 and a total water use of 14,544 acre-feet, resulting in an estimated use factor of 178 gallons per capita per day, or approximately 0.20 acre-feet per person per year.

This use factor is generally consistent with values calculated using 2021 through 2024 data and was therefore determined to be representative of recent and future demand conditions for this user class.

In 2025, the small water system and rural domestic population within Subregion 3 was estimated at approximately 12,580. However, because the Morongo Subarea is not part of the Mojave Basin Area adjudication, no comparable Watermaster reporting framework exists to track small water system and rural domestic production outside the service areas of HiDesert Water District and Joshua Basin Water District. Thus, future demands for this user class in Subregion 3 were estimated by applying the 0.20 acre-foot per person per year use factor developed from Subregions 1 and 2 to the Subregion 3 small water system and rural domestic population projections.
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The resulting demand forecast was developed by applying the representative 0.20 acre-foot per person per year use factor to the small water system and rural domestic population projections presented in Table 6-2. Projected demands for this user class are summarized by Subregion in Table 6-8 and rounded to the nearest 5 acre-feet.

TABLE 6-8: PROJECTED SMALL WATER SYSTEM AND RURAL DOMESTIC DEMAND 2030-2050 (AFY) Helendale Community Services District represents a notable component of the small water system and rural domestic demand forecast in Subregion 1. In 2025, Helendale CSD accounted for approximately 13% of Subregion 1’s small water system and rural domestic demand. Although Helendale CSA does not currently meet the UWMPA reporting threshold and is therefore not required to prepare an individual UWMP, it is one of the larger small retail water suppliers within the Mojave Region and is approaching the statutory threshold for UWMP preparation. Appropriately, Helendale CSD was included in MWA’s wholesale demand forecast and coordinated during development of the RUWMP, but its demands are addressed within this MWA wholesale chapter rather than in a separate retailer chapter.

6.6.1.2 Agricultural Use
Like the majority of groundwater users governed by the MBA Adjudication, agricultural users are assigned an FPA that is monitored by the Mojave Watermaster. Agricultural use has historically represented one of the larger water use categories in the Mojave Region; however, agricultural demands have declined substantially over the past several decades as production has adjusted to the adjudication framework and changing land use conditions.

Watermaster Annual Production Reports prepared since the 2020 MWA Wholesale UWMP indicate that agricultural has continued to decline below levels previously projected, particularly in the Centro and Baja Subareas where some agricultural lands have converted to solar development.47
For purposes of this 2025 RUWMP, the 2025 agricultural demand of approximately 14,500 acre-feet is considered representative of long-term planning conditions. Therefore, agricultural demands are held constant by Subregion through 2050. The resulting agricultural demand forecast, rounded to the nearest five acre-feet, is presented in Table 6-9. 47 Regional Agricultural Water Use from 2021 through 2025 is presented in Table 4-1.

Subregion 2030 2035 2040 2045 2050
Subregion 1 11,550 11,370 10,925 10,420 9,310
Subregion 2 2,805 2,760 2,650 2,530 2,260
Subregion 3 2,475 2,435 2,340 2,230 1,995
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TABLE 6-9: PROJECTED AGRICULTURAL DEMAND 2030-2050 (AFY)

6.6.1.3 Industrial, Golf Course, and Recreational Uses
Industrial, recreational, and golf course uses outside the service area boundaries of the participating urban water retail suppliers were forecast separately from the small water system, rural domestic and agricultural demands. For the adjudicated portions of MWA’s service area, these uses are tracked by the Mojave Watermaster and reported in the Watermaster Annual Production Reports. Based on recent reporting, these use categories have shown modest declines between 2021 and 2025, with no identified growth trend or known development activity indicating a near-term increase in demand.

For purposes of this 2025 RUWMP, 2025 water use was determined to be representative of long-term planning conditions for industrial, recreational, and golf course uses. Accordingly, the 2025 demand values are held constant by subregion through 2050. For Subregion 3, demands outside the service area boundaries of Hi-Desert Water District and Joshua Basin Water District were estimated using publicly available aerial imagery, remote sensing data, and land use information as the Morongo Subarea is not subject to a centralized Watermaster reporting framework. The resulting demand forecast, rounded to the nearest five acre-feet, is presented in Table 6-10.
48 A spatial review using aerial imagery, remote sensing data, and land use information confirmed the no agricultural use in Subregion 3. This review was conducted because the Morongo Subarea is not subject to a centralized Watermaster reporting framework comparable to the MBA adjudicated subareas.

Subregion 2030 2035 2040 2045 2050
Subregion 1 3,000 3,000 3,000 3,000 3,000
Subregion 2 11,500 11,500 11,500 11,500 11,500
Subregion 348 0 0 0 0 0
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TABLE 6-10: PROJECTED INDUSTRIAL, RECREATIONAL, AND GOLF COURSE DEMAND 2030-2050 (AFY) Subregion 2030 2035 2040 2045 2050
Industrial
Subregion 1 4,400 4,400 4,400 4,400 4,400
Subregion 2 2,600 2,600 2,600 2,600 2,600
Subregion 3 335 335 335 335 335
Recreational
Subregion 1 5,400 5,400 5,400 5,400 5,400
Subregion 2 1,800 1,800 1,800 1,800 1,800
Subregion 3 50 50 50 50 50
Golf Course
Subregion 1 5,000 5,000 5,000 5,000 5,000
Subregion 2 0 0 0 0 0
Subregion 3 215 215 215 215 215
The forecasts presented in Tables 6-8 through 6-10 represent the water demand components within MWA’s service area that are outside the service area of the participating urban water retail suppliers. These forecasts are not intended to replace or duplicate the regional demand summaries presented in Chapter 4 – Water Use Characterization. Rather, they provide the supporting other-use demand values that are combined with the applicable retailer demand forecasts to develop the Subregion and regional demand totals presented in Tables 4-5 through 4-8. The integrated regional demand forecast is then carried forward into Chapter 5 – Regional Water Service Reliability.
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Mojave Water Agency Sub-Chapter 6.7 – Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 6-40
Sub-Chapter 6.7 – Water
Conservation and Shortage
Response
Pursuant to CWC Sections 10631(e) and 10632, this sub-chapter summarizes the MWA’s demand management measures and water shortage response framework. As a wholesale urban water supplier, MWA’s conservation and shortage response responsibilities differ from those of the participating retail water suppliers. MWA does not generally provide direct retail water service; rather, it supports regional water reliability through imported water management, groundwater recharge, stored water management, regional conservation coordination, and administration of adjudicated groundwater management responsibilities.

MWA’s demand management efforts are focused on supporting efficient regional water use, coordinating conservation messaging and programs with participating agencies, and maintaining long-term reliability of the groundwater supplies that serve the Mojave Region.

These efforts complement the retail-level demand management measures implemented by the participating urban water retail suppliers within their respective service areas.

MWA’s Water Shortage Contingency Plan (WSCP), adopted with the 2020 UWMP and readopted as part of this 2025 RUWMP, provides the Agency’s framework for evaluating water supply conditions and responding to potential shortages. The WSCP addresses water supply reliability, Annual Water Supply and Demand Assessment procedures, six standard shortage levels, shortage response actions, communication protocols, legal authorities, financial considerations, reevaluation procedures, and plan adoption and availability. Because MWA’s role is regional and wholesale in nature, implementation of the WSCP emphasizes coordination with retail water agencies, management of available imported and stored supplies, and actions to mitigate extended drought conditions or catastrophic interruptions to regional water supply availability.

No substantive changes have been made to MWA’s 2020 WSCP for purposes of this 2025 RUWMP. However, the water supply reliability analysis, demand forecasts, drought risk assessment, and related planning assumptions have been updated through the 2025 RUWMP. Accordingly, the WSCP remains applicable as MWA’s shortage response framework, while the updated reliability findings presented in this chapter and in Chapter 5 – Regional Water Service Reliability provide the current basis for evaluating supply conditions over the planning horizon.
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Mojave Water Agency Sub-Chapter 6.7 – Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 6-41
A complete description of MWA’s WSCP, including detailed implementation procedures and supporting documentation, is provided in Appendix 4.

6.7.1 Demand Management Measures
MWA has implemented a broad set of demand management measures (DMMs) to promote efficient use of water resources and support long-term regional water supply reliability.

Because MWA functions primarily as a wholesale water supplier, State Water Project contractor, and regional groundwater management agency, its DMMs differ from those implemented by retail water suppliers. MWA does not generally provide direct retail water service or regulate day-to-day customer water use within the service areas of participating urban water retail suppliers. Instead, MWA’s DMMs focus on regional conservation coordination, public education and outreach, technical support, water use efficiency programs, regional supply planning, and management of imported and stored water supplies.

MWA’s DMMs are implemented in coordination with participating retail agencies, small water systems, rural domestic users, and other regional water users. These efforts complement the retail-level DMMs described in the individual retailer chapters of this RUWMP and help provide a consistent regional framework for water conservation, efficient water use, and long-term reliability planning.

MWA will continue to implement and refine its DMMs to support efficient water use, regional water supply reliability, and compliance with applicable State requirements. Additional information regarding MWA’s foundational, recent, and planned DMM activities is provided in the following subsections.

6.7.2 Foundational Demand Management Measures
MWA’s foundational DMMs remain generally consistent with those described in the 2020 UWMP and continue to serve as the basis for regional conservation and water use efficiency efforts. These measures include metering of imported water deliveries, public education and outreach, conservation program coordination and staffing support, distribution system asset management for MWA-owned facilities, and wholesale supplier assistance.

Water Measurement and Accounting
MWA measures State Water Project deliveries received through its turnouts and tracks water delivered to recharge, recovery, and other Agency-managed facilities. These data support regional water accounting, operational planning, and long-term supply reliability analyses. 491
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Public Education and Outreach
MWA implements public education and outreach programs to promote efficient water use throughout the Mojave Region. These efforts include conservation messaging, educational materials, public presentations, workshops, community events, and coordination with regional partners such as the Alliance for Water Awareness and Conservation.

Conservation Program Coordination and Staffing Support
MWA supports regional conservation through dedicated program coordination, staffing, and funding. These efforts include technical and administrative support for conservation programs, participation in regional events and conferences, and support for rebate, education, and outreach activities that encourage efficient water use across the Region.

MWA-Owned Facility Management
MWA operates and maintains facilities associated with imported water delivery, recharge, recovery, and regional water supply management. MWA monitors and maintains these facilities to support reliable operations, accurate flow measurement, water quality compliance where applicable, and efficient use of imported and stored water supplies.

Wholesale Supplier Assistance
MWA provides technical, financial, and programmatic assistance to retail suppliers and regional partners to support conservation and water-use efficiency. This assistance includes coordination through regional conservation programs, support for public information and education efforts, and implementation of programs that help retail suppliers and their customers reduce demand where appropriate.

6.7.2.1 Recent DMM Activities
Since the 2020 UWMP, MWA has continued to implement regional conservation, education, and coordination activities. These efforts have included continued public outreach, regional conservation messaging, coordination with participating retail agencies, support for conservation programs, and development of updated regional planning analyses through the 2025 RUWMP.

6.7.2.2 Planned DMM Activities
MWA will continue implementing DMMs that reflect its wholesale and regional water management role. Planned activities include continued coordination with participating retail agencies, ongoing public education and outreach, support for regional conservation programs, continued measurement and accounting of imported and stored supplies, and maintenance of MWA-owned facilities needed to support long-term regional water supply reliability.
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6.7.3 Water Shortage Contingency Plan
MWA has adopted a WSCP in accordance with CWC Section 10632. The WSCP establishes a structured framework for evaluating regional water supply conditions, coordinating with retail water suppliers, and implementing appropriate response actions during drought, constrained imported water conditions, or other supply interruptions. Because MWA functions as a wholesale water supplier, SWP contractor, and regional groundwater management agency, the WSCP is focused on regional supply management and coordination rather than direct regulation of retail customer water use.

6.7.3.1 Summary of Water Shortage Levels and Response
Actions
MWA’s WSCP includes six standard shortage stages corresponding to progressively severe shortage conditions of up to 10%, 20%, 30%, 40%, 50% and greater than 50%. These stages provide a consistent framework for evaluating the relative severity of regional supply constraints. However, unlike retail shortage stages, MWA’s stages are implemented primarily through wholesale and regional water management actions, including use of stored supplies, access to flexible or alternative supplies, coordination of voluntary demand reduction messaging, and operational adjustments to MWA facilities, including R-Cubed deliveries where appropriate.
• Stage 1 – Up to 10% Shortage:

During Stage 1, MWA may access stored supplies, as needed, to address supply deficits. MWA may also coordinate voluntary conservation messaging with retail agencies, public agencies, and the broader community to encourage efficient water use and communicate the potential for future shortage conditions. • Stage 2 – Up to 20% Shortage:

During Stage 2, MWA may continue to access stored supplies while increasing coordination with retail agencies. MWA may also implement voluntary demand reduction messaging and reduce R-Cubed deliveries, as appropriate, to help align supply availability with projected demands.
• Stage 3 – Up to 30% Shortage:

During Stage 3, MWA may intensify regional coordination, continue use of stored supplies, and further evaluate operational adjustments to MWA-managed facilities. RCubed deliveries may be reduced in coordination with affected retail agencies, while voluntary demand reduction messaging may be expanded to address increased severity of the shortage condition.
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• Stage 4 – Up to 40% Shortage:

During Stage 4, MWA may continue to rely on stored supplies, voluntary demand reduction, and reduced R-Cubed deliveries as appropriate. At this stage, MWA would evaluate regional supply conditions, operational constraints, and available management actions to preserve stored water assets and maintain reliability for essential regional needs.
• Stage 5 – Up to 50% Shortage:

During Stage 5, MWA may implement more intensive regional supple management actions, including increased reliance on stored supplies, pursuit of alternative supplies, and continued operational coordination with retail agencies. MWA may also further reduce R-Cubed deliveries where appropriate and expand regional communication regarding shortage conditions and available response actions. • Stage 6 – Greater than 50% Shortage:

During Stage 6, MWA would implement emergency-level regional supply management actions necessary to address severe shortage conditions or catastrophic supply interruptions. These actions may include use of available stored supplies, pursuit of alternative supplies or transfers, operational adjustments to MWA facilities, reduction of R-Cubed deliveries, and close coordination with retail agencies, DWR, SWP contractors, and other regional partners to support continued water supply reliability for essential needs.

6.7.3.2 Summary of Monitoring Procedures and
Implementation
MWA conducts an Annual Water Supply and Demand Assessment each year in accordance with CWC requirements. These assessments are prepared and submitted to DWR by July 1 and evaluate anticipated regional water supply and demand conditions over a rolling twelve-month period spanning July through June. The Annual Assessment serves as the primary mechanism for evaluating near-term supply reliability and determining whether implementation of one or more WSCP shortage stages may be warranted.

MWA has completed and submitted an Annual Assessment each year since 2022, as required by statute. While the results of these assessments are not included in this RUWMP, the methodology and demand assumptions applied are consistent with those presented in this chapter and in Chapter 5 – Regional Water Service Reliability. The Annual Assessment considers available regional supplies, projected demands, infrastructure capability, imported water availability, stored water assets, and other locally applicable factors that may influence water supply reliability.

Implementation of the WSCP relies on coordination among MWA staff, retail water suppliers, regional partners, stakeholders, and the public. During shortage conditions, MWA may 494
Mojave Water Agency Sub-Chapter 6.7 – Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 6-45
communicate regional supply conditions, shortage stage determinations, available response actions, and recommended coordination measures to retailer water suppliers, regional partners, stakeholders, and the public. This approach supports consistent messaging while allowing retail suppliers to implement customer-level shortage response actions within their respective service areas.
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Mojave Water Agency Sub-Chapter 6.8 – Water System Reliability and Drought Risk Assessment 2025 Mojave RUWMP – Public Draft 6-46
Sub-Chapter 6.8 – Water System
Reliability and Drought Risk
Assessment
MWA’s water system reliability and drought risk assessment findings are presented in Chapter 5 – Regional Water Service Reliability. The reliability analysis is informed by the MWA-specific supply and operational information presented in this chapter, including imported water supply availability and reliability considerations described in Sub-Chapter

6.4, managed groundwater storage described in Sub-Chapter 6.5, and MWA’s wholesale demand forecast for uses outside the participating retail supplier service areas described in Sub-Chapter 6.6. These MWA-specific inputs are combined with the regional supply characterization presented in Chapter 3 – Regional Supply Characterization and the regional water use forecast presented in Chapter 4 – Water Use Characterization to evaluate regional reliability under the UWMPA-required considerations. Chapter 5 integrates these assumptions to satisfy the applicable water system reliability and drought risk assessment requirements, including the Five-Year Drought Risk Assessment, normal year, single dry year, and five consecutive dry year analyses through 2050.

The results demonstrated in Chapter 5 demonstrate that the Mojave Region’s water supply portfolio is capable of meeting the water uses in the Region in normal, single dry, and five consecutive dry years from 2025 through 2050.
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Mojave Water Agency Sub-Chapter 6.9 – Energy Intensity Analysis 2025 Mojave RUWMP – Public Draft 6-47
Sub-Chapter 6.9 – Energy Intensity
Analysis
Pursuant to CWC Section 10631.2, this sub-chapter summarizes energy use associated with MWA’s water management operations to the extent such information is readily available.

MWA’s energy reporting differs from a traditional retail water supplier because the Agency does not generally operate a retail potable water distribution system or deliver water directly to end-use customers. Instead, MWA’s primary operations consist of importing SWP supplies, conveying water to recharge locations, placing water into groundwater storage, and managing regional water supply reliability. Accordingly, the energy information presented in this sub-chapter focuses on MWA-controlled water management processes for which energy and water volume data are readily obtainable, including conveyance, recharge, recovery, and related operations, as applicable.

The principal exception to MWA’s recharge-focused operating model is the Regional Recharge and Recovery Project, or R-Cubed, which stores imported supplies in the Floodplain Aquifer and, when needed, recovers and delivers that water through MWA-owned wells and pipelines directly to participating retail water suppliers. Because R-Cubed includes recovery and direct delivery components, its energy use is included in MWA’s energy evaluation where data are readily available.

TABLE 6-11: ENERGY INTENSITY – TOTAL UTILITY APPROACH FOR MONTH YEAR THROUGH MONTH YEAR Sum of All Water Management Processes
Volume of Water Entering Process (acre-feet)
Energy Consumed (kWh)
Energy Intensity (kWh/acre-foot)
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2025 Mojave RUWMP – Public Draft 7-1
Chapter 7.0 THE CITY OF ADELANTO
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TABLE OF CONTENTS
Sub-Chapter 7.1 - Introduction ...........................................................................................................................7-7

7.1.1 Background and Purpose.......................................................................................................................................................7-7

7.1.2 Basis for Plan Preparation ..................................................................................................................................................... 7-8

7.1.3 Coordination and Outreach ................................................................................................................................................ 7-8

7.1.4 RUWMP Adoption......................................................................................................................................................................... 7-9

7.1.5 Document Organization........................................................................................................................................................ 7-10 Sub-Chapter 7.2 – Water Service and System Description..........................................................................7-11

7.2.1 Service Area Climate............................................................................................................................................................... 7-13 Sub-Chapter 7.3 – Population, Land Use, Economy, and Demographics.................................................7-14

7.3.1 Current Population and Historic Trends......................................................................................................................7-14

7.3.2 Projected Population ............................................................................................................................................................... 7-15

7.3.3 Current and Projected Land Use......................................................................................................................................7-16

7.3.4 Economic Trends & Other Social and Demographic Factors....................................................................... 7-17 Sub-Chapter 7.4 – Water Supply and Infrastructure Characterization ...................................................7-18

7.4.1 Groundwater................................................................................................................................................................................. 7-18

7.4.2 Groundwater Quality ............................................................................................................................................................... 7-21

7.4.3 Recycled Water Supplies .....................................................................................................................................................7-24

7.4.4 Desalination Opportunities.................................................................................................................................................7-24

7.4.5 Water Transfers and Exchanges.....................................................................................................................................7-24

7.4.6 Supply Summary.......................................................................................................................................................................7-25

7.4.7 Delivery System Details.........................................................................................................................................................7-26 Sub-Chapter 7.5 – Water Use Characterization........................................................................................... 7-28

7.5.1 Current Customer Water Use............................................................................................................................................7-29

7.5.2 Compliance with Water Use Targets and Objectives.......................................................................................7-33

7.5.3 Forecasting Customer Use.................................................................................................................................................7-34

7.5.4 Forecasting Water Use for DRA and Annual Assessment.............................................................................. 7-37

7.5.5 Projecting Disadvantaged Community Water Use............................................................................................7-39 Sub-Chapter 7.6 – Water Conservation and Shortage Response ............................................................7-40

7.6.1 Demand Management Measures ................................................................................................................................ 7-40 499
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7.6.2 Foundational Demand Management Measures ..................................................................................................7-41

7.6.3 Water Shortage Contingency Plan................................................................................................................................7-43 Sub-Chapter 7.7 – Water System Reliability and Drought Risk Assessment .........................................7-46

7.7.1 Five Year Drought Risk Assessment............................................................................................................................. 7-46

7.7.2 Long Term Service Reliability.............................................................................................................................................7-47

7.7.3 Annual Reliability Assessment ........................................................................................................................................ 7-49

7.7.4 Water Supply Reliability Summary................................................................................................................................7-50 Sub-Chapter 7.8 – Energy Intensity Analysis ................................................................................................7-51 500
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LIST OF TABLES
Table 7-1: Public Water System Information ...................................................................................................................................... 7-8 Table 7-2: Customer Water Service Connections......................................................................................................................... 7-12 Table 7-3: Historical Population................................................................................................................................................................. 7-15 Table 7-4: Population Growth Rate – 2015-2024............................................................................................................................ 7-15 Table 7-5: Population Forecast and Growth Rate .........................................................................................................................7-16 Table 7-6: Last Five Years of the City’s FPA Supply (AFY)..........................................................................................................7-19 Table 7-7: Projected Mojave Adjudication FPA for the City through 2030 (AFY) .......................................................7-19 Table 7-8: Projected Mojave Adjudication FPA for the City through 2050 (AFY)......................................................7-20 Table 7-9: Last Five Years of Replacement and Make-up Water Supplies (AFY)..................................................... 7-21 Table 7-10: City’s Potable Water Quality .............................................................................................................................................7-23 Table 7-11: City’s Managed Groundwater Production 2021-2025 (AFY) ........................................................................7-25 Table 7-12: City’s Projected Managed Groundwater Supply 2026 – 2030 (AFY)......................................................7-26 Table 7-13: City’s Projected Managed Groundwater Supply Through 2050 (AFY)..................................................7-26 Table 7-14: Potable Customer Use 2021-2025 (AF)....................................................................................................................... 7-31 Table 7-15: Distribution System Loss 2021 - 2024 ..........................................................................................................................7-33 Table 7-16: Forecast Future Water Use (Values in Acre-feet per year)..........................................................................7-36 Table 7-17: Forecast DRA Water Use for 2026 through 2030 (AFY) ....................................................................................7-39 Table 7-18: Five Year Drought Risk Assessment (AFY)................................................................................................................7-47 Table 7-19: Normal and Single Dry Year Water Supply and Demand through 2050 (AFY).............................. 7-48 Table 7-20: Five Consecutive Dry Years Water Supply and Demand through 2050 (AFY).............................. 7-49 Table 7-21: Energy Intensity – Total Utility Approach for Dec 2024 through Dec 2025..........................................7-51 501
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LIST OF FIGURES
Figure 7-1: City of Adelanto Water City Service Area................................................................................................................... 7-12 Figure 7-2: Potable Water System........................................................................................................................................................... 7-27 502
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APPENDICES
Appendix 7A – The City of Adelanto WSCP ......................................................................................................................................... A-5 Appendix 7B – The City of Adelanto DWR Checklist......................................................................................................................A-6 503
The City of Adelanto Sub-Chapter 7. 1 - Introduction
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Sub-Chapter 7.1 - Introduction
The City of Adelanto (City) operates as a retail water supplier, providing water and wastewater services through the Adelanto Public Utilities Authority (APUA/Authority), a component unit of the City. The City Council serves as the governing body for the Authority and oversees its operations.

Adelanto is located on U.S. Highway 395, in the western portion of California’s Mojave Desert in southwestern San Bernardino County. The City is situated 35 miles north of the City of San Bernardino, via Interstate 15. Elevations within the City range approximately between 2,700 and 3,200 feet above mean sea level. The terrain generally slopes from southwest to northeast. The terrain has allowed the development to occur mostly in Assessment City 1A and towards the northern end of the City. The City’s key planning objectives include responsible growth for its rural, suburban, agricultural, commercial, and industrial land uses, paired with economic development that attracts and maintains quality business and industry while being beneficial to its residents.

The City’s water supply is sourced almost entirely from groundwater pumped from the Mojave River Groundwater Basin. Ensuring an adequate and reliable water supply for current and future customers is fundamental to the City’s mission. Through participation in the 2025 Mojave RUWMP (2025 RUWMP), the City supports coordinated, basin-wide planning. Regional conditions and assumptions are presented in the 2025 RUWMP regional chapters, while this chapter focuses on City-specific system characteristics, demands, demand management measures, and reliability.

7.1.1 Background and Purpose
The City has ensured compliance with the Urban Water Management Plan Act (UWMPA) requirements for urban water suppliers through its participation in the 2025 RUWMP and preparation of this retail-specific chapter.49 The UWMPA requires urban water suppliers to evaluate the adequacy of their water supplies to meet projected demands under average conditions, single dry years, and multiple dry year scenarios through a 20-year planning horizon. This chapter presents the City’s evaluation of these requirements and demonstrates its ability to meet anticipated demands under normal and drought conditions.

The 2025 RUWMP, together with this retail-specific chapter, updates the City’s 2020 Urban Water Management Plan (UWMP) and incorporates new data, analyses, and regulatory 49 California Water Code Sections 10610 through 10657.
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guidance issued since 2020 by the California Department of Water Resources (DWR) pursuant to the California Water Code (CWC). In addition to satisfying statutory requirements, the 2025 RUWMP serves as a comprehensive planning document describing existing and future water supplies, projected water demands, demand management progress, and actions necessary to maintain long-term supply reliability. The regional plan also documents cooperative efforts among participating agencies to efficiently manage shared resources and address future water needs across the RUWMP Planning Area.

7.1.2 Basis for Plan Preparation
The City operates a Public Water System as described in California Health and Safety Code Section 116275. The City is also classified as an Urban Water Supplier pursuant to CWC Section 10617, as it provides water for municipal purposes to more than 3,000 service connections and supplies more than 3,000 acre-feet of water annually. These qualifications require the preparation and adoption of an UWMP every five years. Under CWC Section 10620 (d)(1), these requirements may be satisfied through participation in a RUWMP, which the City and the other Urban Water Suppliers within the RUWMP Planning Area have elected to prepare collaboratively. Details of the City’s Public Water System are provided in Table 7-1.

TABLE 7-1: PUBLIC WATER SYSTEM INFORMATION
Public Water System Number Public Water System Name Number of Municipal Connections CA3610001 City of Adelanto ~8,878

7.1.3 Coordination and Outreach
Preparation of the 2025 RUWMP involved coordination among the participating Urban Water Suppliers and the Mojave Water Agency (MWA), which serves as the region’s wholesale water supplier. This coordination ensured consistency in assumptions, methodologies and regional analyses. The City actively participated in this collaborative process through technical meetings, data sharing, and review of draft materials addressing both regional conditions and City-specific operations.

As required by the UWMPA, the City coordinated with nearby agencies during development of this chapter to ensure consistency with related land use and water resource planning efforts, including General Plans, Water Master Plans, and Specific Plans associated with anticipated development.

Consistent with CWC Section 10641, the City encouraged the active participation from a broad cross-section of the community representing diverse social, cultural, and economic interests within its service area during preparation of this chapter. Public notice of the plan’s 505
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availability and the scheduled public hearing was provided, and a public hearing was conducted prior to adoption to solicit input from customers, stakeholders, and interested parties.

Comprehensive documentation of the regional planning process, including interagency coordination, formal notifications provided in accordance with CWC Section 10621(b), stakeholder engagement, and outreach activities conducted on behalf of all participating agencies, is provided in Sub-Chapter 1.1.3 Coordination and Outreach of Regional Chapter 1 - Introduction.

7.1.3.1 Water Supplier Information Exchange
Compliance with CWC Section 10631 is described in Sub-Chapter 1.1.3 Coordination and Outreach of Regional Chapter 1 – Introduction.

7.1.4 RUWMP Adoption
The City held a public hearing regarding the 2025 RUWMP on June, 10, 2026. Before the hearing, the City made a draft of the 2025 RUWMP available for public inspection at City Hall, 11600 Air Expressway Adelanto, CA 92301, and on the City’s website. Pursuant to CWC Section 10642, general notice of the public hearing was provided through publication of the hearing date and time in the local press as required under the UWMPA.

The City’s elected body adopted this 2025 RUWMP on June, 10, 2026. A copy of the 2025 RUWMP will be submitted to DWR, provided to the County and the California State Library, and posted onto the City’s website.

The City plans to submit all required documentation related to the UWMPA through the DWR submittal website soon after adoption, including the on-line submittal of information associated with the following DWR Excel workbooks:
• “FINAL Submittal 2025 UWMP Tables – City of Adelanto – 06.01.2026.xls” • “Appendix F 2025 Checklist – City of Adelanto – 06.01.2026.xls” 506
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7.1.5 Document Organization
This chapter is organized as follows:
• Sub-Chapter 7.2 Water Service and System Description
• Sub-Chapter 7.3 Population, Land Use, Economy, and Demographics • Sub-Chapter 7.4 Water Supply and Infrastructure Characterization • Sub-Chapter 7.5 Water Use Characterization
• Sub-Chapter 7.6 Water Conservation and Shortage Response • Sub-Chapter 7.7 Water System Reliability and Drought Risk Assessment • Sub-Chapter 7.8 Energy Intensity Analysis
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Sub-Chapter 7.2 – Water Service and
System Description
The City of Adelanto provides potable water service to the residents and businesses within its service area, as depicted in Figure 7-1, which corresponds to the City’s jurisdictional boundaries.

Water service in City relies entirely on groundwater extracted from wells located throughout the service area. The City manages six active wells that tap into local aquifers to meet local demand and maintains an emergency intertie connection with the City of Victorville for backup supply. An additional eight inactive wells are maintained by the City and may be returned to service in the future. Once extracted, groundwater is treated to meet all applicable federal and state water quality standards and is either directed into the distribution system or stored in one of the City’s eight steel storage tanks, which collectively provide more than 21 million gallons of storage. These reservoirs help ensure that the community has access to adequate water during periods of high demand, particularly in the summer months.

The City’s water system encompasses an extensive distribution network designed to deliver water efficiently to homes, businesses, and fire protection systems. The system includes over 113 miles of water mains, eight booster pump stations, several pressure-reducing stations, thousands of service connections, thousands of valves and fire hydrants that allow the City to isolate portions of the system for maintenance or emergencies without disrupting service to the broader community. Table 7-2 summarizes recent historical service connections by customer type, providing an overview of the composition of the City’s customer base. The City contracts with Woodard and Curran to engage in regular inspection, maintenance, management, and replacement of system components to ensure long-term reliability and safety of the water supply.

While the APUA currently discharges treated effluent from the Adelanto Wastewater Treatment Facility to percolation ponds, the City is continuing to explore the development of a recycled water program. Planned improvements are focused on enabling the beneficial reuse of treated effluent, including development of recycled water storage and distribution infrastructure to support non-potable uses such as irrigation and dust control. These efforts are intended to enhance long-term water supply reliability, reduce reliance on groundwater, and support sustainable water management within the community. 508
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FIGURE 7-1: CITY OF ADELANTO WATER CITY SERVICE AREA
TABLE 7-2: CUSTOMER WATER SERVICE CONNECTIONS
Customer Class 2021 2022 2023 2024 2025
Single-Family Residential 8,329 7,880 7,308 7,940 8,326 Multi-Family Residential 82 81 415 591 169
Commercial/Institutional 159 159 169 249 243
Industrial 166 169 109 122 104
Landscape Irrigation 41 29 30 36 36
Total 8,777 8,318 8,031 8,938 8,878
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7.2.1 Service Area Climate
Located in California’s Mojave Basin Area, the City’s service area experiences a climate characteristic of the High Desert. The region is highly arid due to the rain shadow effect of surrounding mountain ranges and is marked by hot summers and relatively cool winters. This results in low precipitation and pronounced diurnal temperature variations throughout the year. Average annual precipitation is minimal, with a 30-year average of 5.52 inches, occurring primarily as rainfall between December and March and generally tapers off by May. While late summer monsoonal thunderstorms may contribute episodic precipitation, these events typically account for only a small portion of total annual precipitation. Although snowfall is rare, winter snowfall averages 1.4 inches annually. The annual average temperature is approximately 61 degrees Fahrenheit; however, the High Desert climate produces significant seasonal extremes, with summer temperatures frequently exceeding 100 degrees and winter lows occasionally falling below freezing. Overall, the City’s service area climate is generally consistent with climatic conditions across the RUWMP Planning Area. A more detailed discussion of Planning Area’s climate characteristics is provided in SubChapter 2.1.5 Climate of Regional Chapter 2 – The Mojave Region.

7.2.1.1 Climate Change
Climate change is driven by increasing concentrations of atmospheric carbon dioxide and other greenhouse gases, resulting in rising temperatures and greater hydrologic variability.

These effects underscore the importance of considering climate change in this 2025 RUWMP.

While the CWC does not prescribe specific climate change planning or management measures for retail water suppliers, it emphasizes that climate change is an appropriate consideration for general water management and planning. Accordingly, climate change is a critical factor in assessing the availability and reliability of water supplies, as well as future demand projections. A detailed discussion of climate change impacts on the City’s water supplies and demands, as well as those of the RUWMP Planning Area at-large, is provided in Sub-Chapter 2.1.5 Climate of Regional Chapter 2 – The Mojave Region. 510
The City of Adelanto Sub-Chapter 7.3 - Population, Land Use, Economy, and Demographics 2025 Mojave RUWMP – Public Draft 7-14
Sub-Chapter 7.3 – Population, Land
Use, Economy, and Demographics
Service area population and land use projections are critical to developing a useful planning framework as population dynamics and growth are a primary influence on water use. These projections directly influence planning measures for system supply, delivery, infrastructure, and demand management. Similarly, understanding the City’s economic, social, and demographic trends give valuable insight to water management and planning. This subchapter addresses these factors to provide a supportable basis for forecasting future water use.

7.3.1 Current Population and Historic Trends
Population estimates for the City are based on the population forecast prepared in 2020 by the Center for Economic Forecasting and Development at the University of California, Riverside (UCR Study), which was commissioned by MWA as part of the 2020 Urban Water Management Plan cycle. The UCR Study developed population estimates for the entire MWA service area as well as for individual retailer water supplies using a comprehensive economic and demographic modeling approach.

In 2023, as part of MWA’s Master Plan development, the agency reviewed and refined the UCR Study population projections using updated information not available during the study’s development, including 2020 Census data and other available demographic indicators, to ensure that near-term population levels and growth patterns were accurately represented.

Where appropriate, adjustments were applied to align study estimates with observed population totals while maintaining the long-term growth trajectory established by the UCR Study.

Population projections for the City reflect these regionally refined UCR Study estimates and therefore align with those used by the other retailers party to the 2025 RUWMP. This approach ensures that demand projections developed for participating parties are consistent with basin-wide planning assumptions and analyses. Detailed methodologies used to develop and refine the regional population projections included in the UCR Study are presented in Sub-Chapter 2.1.6 Current and Projected Population of Regional Chapter 2 – The Mojave Region.

Adelanto originated in the late 19th century as a small railroad and agricultural settlement in the High Desert and remained sparsely populated for much of the 20th century. Significant 511
The City of Adelanto Sub-Chapter 7.3 - Population, Land Use, Economy, and Demographics 2025 Mojave RUWMP – Public Draft 7-15
population increase occurred following incorporation in 1970, driven by residential development and improved regional connectivity. Growth accelerated between 2000 and 2020, during which the City’s population approximately doubled, reflecting sustained suburban expansion and housing development that exceeded broader regional growth rates.

Continued development and land availability within the service area are expected to support additional population growth over the planning horizon.

Table 7-3 presents the City’s historical population while Table 7-4 presents the City’s population growth over the last decade. The population values reflect the City’s service area, which generally corresponds to the City of Adelanto’s boundaries as shown in Figure 7-1, but excludes small portions of the City near the Southern California Logistics Airport.

TABLE 7-3: HISTORICAL POPULATION
TABLE 7-4: POPULATION GROWTH RATE – 2015-2024

7.3.2 Projected Population
CWC Section 10631(a) requires urban retail water agencies to evaluate their projected service area populations while considering past growth rates, economic conditions, and anticipated land use changes. Coordination with local land use planning efforts helps ensure that anticipated development patterns are appropriately represented in long-term demand forecasting.

Population growth within the City is projected to increase moderately over the planning horizon, reflecting continued residential development, available land for expansion, and regional housing demand within the High Desert. Growth is expected to occur primarily through suburban residential expansion supported by commercial and service development needed to accommodate new residents, rather than through significant urban densification.

While growth rates are anticipated to moderate over time, overall population is expected to continue increasing throughout the planning horizon, consistent with broader regional trends within the RUWMP Planning Area. More broadly, incorporated areas served by municipal water providers within the RUWMP Planning Area are projected to accommodate a substantial 1990 2000 2010 2015 2020 2025
6,751 17,895 31,760 33,786 37,959 44,588
2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
Population 33,786 34,362 35,186 35,156 35,130 37,959 39,285 40,611 41,936 43,262 Growth Rate 1.70% 2.40% -0.09% -0.07% 8.05% 3.49% 3.38% 3.26% 3.16% 512
The City of Adelanto Sub-Chapter 7.3 - Population, Land Use, Economy, and Demographics 2025 Mojave RUWMP – Public Draft 7-16
share of future regional population growth relative to unincorporated areas as illustrated in Sub-Chapter 2.1.6 Current and Projected Population of Regional Chapter 2 – The Mojave Region.

Table 7-5 presents the City’s projected population and associated growth rates through 2060.

TABLE 7-5: POPULATION FORECAST AND GROWTH RATE

7.3.3 Current and Projected Land Use
The primary land use within the City is residential, consisting largely of low-density, singlefamily housing developments. This land use pattern reflects the City’s role as an affordable residential community within the High Desert region. While predominantly residential, the City also includes industrial and commercial land uses, with development concentrated along with U.S. Highway 395 corridor. As of 2020, the City was approximately 15% built out, indicating substantial capacity for future growth within the existing land use framework.

Future growth within the City is anticipated to occur primarily through continued infill and incremental residential development consistent with historical trends and the population projections described in the prior subsection. The City has not identified any large-scale master planned developments or projects requiring preparation of a Water Supply Assessment that would materially alter projected growth patterns over the current planning horizon. As a result, anticipated development is reflected within the baseline population projections and does not rely on discrete, project-specific assumptions.

Over the long term, the City envisions a gradual transition to a more integrated land use pattern that includes residential expansion supported by industrial, logistics, and renewable energy development. However, this transition is expected to occur incrementally and is not associated with specific large-scale developments that would significantly affect near-term water demand projections.
2025 2030 2035 2040 2045 2050 2055 2060
City of Adelanto 44,588 45,913 47,239 48,565 49,890 51,216 52,542 53,867 Growth Rate 2.97% 2.89% 2.81% 2.73% 2.66% 2.59% 2.52%
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The City of Adelanto Sub-Chapter 7.3 - Population, Land Use, Economy, and Demographics 2025 Mojave RUWMP – Public Draft 7-17

7.3.4 Economic Trends & Other Social and Demographic
Factors
The City’s service area reflects a community undergoing gradual economic transition within the High Desert region. Historically, local economic conditions have been shaped by housing affordability, land availability and proximity to employment centers in the Inland Empire and Southern California. These factors have supported steady population growth, within the City functioning in part as a residential community for commuters working outside the immediate area.

In recent years, the City has sought to expand its economic base through industrial, logistics, and renewable energy development. The City’s location along key regional transportation corridors provides opportunities to support warehousing, distribution, and related commercial activity. However, while these sectors represent an important component of the City’s long-term economic strategy, development has occurred incrementally and has not resulted in large-scale, near-term employment or population shifts beyond those reflected in historical trends. Consistent with these conditions, future economic growth within the service area is expected to occur gradually and in coordination with residential development. As a result, economic factors influencing water demand are generally captured within the population and land use projections described in the two prior subsections. Broader regional economic conditions that influence growth within the City are discussed in Sub-Chapter

2.1.7.2 Economic Trends and Other Social and Demographic Factors of Regional Chapter 2 – The Mojave Region.

Demographically, the service area includes a diverse population with a range of household types, income levels, and housing characteristics. According to the 2020 U.S. Census, the ethnic makeup of the City is 68.3% Hispanic/Latino, 16.8% African American, 8.1% White, and

1.7% Asian, with 37% of the population identifying as two or more races. Median household income levels remain below statewide averages, and a notable portion of the population is classified as disadvantaged.
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The City of Adelanto Sub-Chapter 7.4 - Water Supply and Infrastructure Characterization 2025 Mojave RUWMP – Public Draft 7-18
Sub-Chapter 7.4 – Water Supply and
Infrastructure Characterization
The City relies primarily on groundwater for its water supply. Through a municipal network of six active wells, the City pumps groundwater from the underlying Alto Subarea of the Mojave Basin Area (MBA). As described in Regional Chapter 3 – Regional Water Supply Characterization, the MBA is an adjudicated basin administered by a court-appointed Watermaster. The aforementioned regional chapter describes the MBA’s water supplies and related management structures and details. Generally, the City pumps groundwater that is recharged and managed by MWA.

7.4.1 Groundwater
Groundwater is the primary water supply source for all urban retail water suppliers within the MBA. The City, like many of the MWA’s other retail agencies, pumps groundwater from the adjudicated MBA, specifically the Alto Subarea. The basin is recharged through several means, including natural recharge from the Mojave River, lateral subsurface groundwater movement from the adjacent San Gabriel mountains, imported water from the State Water Project (managed by MWA), and other sources like irrigation runoff, return flows from septic systems and water delivery systems, and treated wastewater effluent. A detailed description of the MBA, Subareas, aquifer characteristics, adjudication, management areas, and other adjudicated basins is presented in Sub-Chapter 3.1.1 Mojave Region Water Supply Sources of Regional Chapter 3 – Regional Water Supply Characterization.

7.4.1.1 City of Adelanto’s Free Production Allowance
Under the Judgment governing the MBA, each producer is assigned a Free Production Allowance (FPA), representing the annual quantity of groundwater that may be extracted without replacement obligations. The City’s FPA is based on historical production coupled with evaluation of groundwater conditions, as administered by MWA in its role as the Watermaster.

The City’s FPA changes over time as the Watermaster assesses supply availability for all adjudicated purveyors against the long-term health and production safe yield of the MBA.

The City’s FPA has continued to be significantly reduced as a percentage of the Base Annual Production (BAP) number. The City’s BAP is tracked as one entry in the Watermaster’s annual report as: “Adelanto, City of”. The City’s BAP in water year 2025 was 5,182 acre-feet per year.

The current 50.4% FPA of this source is 2,612 acre-feet. Table 7-6 presents the City’s FPA for the 515
The City of Adelanto Sub-Chapter 7.4 - Water Supply and Infrastructure Characterization 2025 Mojave RUWMP – Public Draft 7-19
most recent five year period pursuant to the MBA Judgment. Detailed discussion of the adjudication framework and administration of production allowances is provided in Regional Chapter 3 – Regional Water Supply Characterization.

TABLE 7-6: LAST FIVE YEARS OF THE CITY’S FPA SUPPLY (AFY) Year Base Annual Production Percent FPA FPA Supply
2021 5,182 55% 2,850
2022 5,182 50% 2,591
2023 5,182 53.3% 2,762
2024 5,182 50.4% 2,612
2025 5,182 50.4% 2,612
The 50.4% FPA represents a reduction that aligns with the long-term Production Safe Yield considered by the Watermaster. Accordingly, the City’s projected FPA in a normal year, single dry year, and five consecutive dry years through 2030 is set at 50.4% as shown in Table 7-7.

TABLE 7-7: PROJECTED MOJAVE ADJUDICATION FPA FOR THE CITY THROUGH 2030 (AFY)

Although the Production Safe Yield of the MBA appears to be stabilizing in the Alto Subarea, out of an abundance of caution the future FPA has been reduced to 50% to address longterm water supply planning options. Table 7-8 presents the City’s projected FPA in a normal year, single dry year, and five consecutive dry years from 2030 through 2050 at 50%.

Year Type Projected FPA
Normal 2,612
Single Dry-Year 2,612
Multi-Year Drought
2026 (1st Year) 2,612
2027 (2nd Year) 2,612
2028 (3rd Year) 2,612
2029 (4th Year) 2,612
2030 (5th Year) 2,612
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TABLE 7-8: PROJECTED MOJAVE ADJUDICATION FPA FOR THE CITY THROUGH 2050 (AFY) A summary of long-term reliability and other factors that will affect FPA such as hydrological and regulatory issues is provided in Regional Chapter 3 – Regional Water Supply Characterization.

7.4.1.2 Carryover Water Supplies
The City does not currently hold carryover water supplies as part of its overall water supply management in the Alto Subarea.50 Although such supplies may become available in the future, they are not assumed to be available for purposes of this analysis and are therefore not included in the supply availability evaluation presented in this sub-chapter, in order to preserve a conservative assessment of water supply reliability.

7.4.1.3 Replacement and Make-up Water Supplies
The City has taken actions to augment its water supplies through the Watermaster’s water replacement water supply program and by acquiring make-up water supplies. Replacement water supplies are those supplies acquired by the Watermaster in order to replace supplies pumped from the Basin that exceed the City’s annual FPA from the Alto Subarea. Make-up water supplies, by contrast, are acquired to satisfy obligations under the Judgment to maintain flows from the Alto Subarea to downstream subareas when natural conditions and production patterns would otherwise result in a shortfall.

A detailed description of these programs, obligations, and administrative processes is provided in Regional Chapter 3 - Water Supply Characterization. Table 7-9 summarizes the 50 Water Year 2025 Watermaster Report, Appendix H.

Projected FPA 2030 2035 2040 2045 2050
Normal 2,591 2,591 2,591 2,591 2,591
Single Dry-Year 2,591 2,591 2,591 2,591 2,591 Multi-Year Drought Year 1 2,591 2,591 2,591 2,591 2,591
Year 2 2,591 2,591 2,591 2,591 2,591
Year 3 2,591 2,591 2,591 2,591 2,591
Year 4 2,591 2,591 2,591 2,591 2,591
Year 5 2,591 2,591 2,591 2,591 2,591
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quantities of replacement and make-up water supplied to the City during the most recent five-year period.

TABLE 7-9: LAST FIVE YEARS OF REPLACEMENT AND MAKE-UP WATER SUPPLIES (AFY)

7.4.2 Groundwater Quality
Groundwater produced by the City is obtained from wells completed in the Mojave River Groundwater Basin and is treated as necessary to meet all applicable federal and state drinking water standards prior to delivery to customers. Water quality within the basin is influenced by natural hydrogeologic conditions as well as localized land use and recharge patterns. The City routinely monitors groundwater quality in accordance with regulatory requirements to ensure the continued safety and reliability of its potable water supply.

Detailed information regarding the quality of water delivered to customers, including detected constituents, regulatory compliance status, and treatment practices, is provided annually in the City’s Consumer Confidence Report (CCR). The most recent available report is the 2024 CCR, published in June 2025, which reflects water quality data from the 2024 calendar year in accordance with state reporting requirements that mandate annual preparation and distribution of CCRs by July 1 of the following year. The CCR summarizes monitoring results for the most recent reporting year and demonstrates compliance with primary drinking water standards established by the U.S. Environmental Protection Agency and the State Water Resources Control Board Division of Drinking Water (SWRCB). The City’s most recent CCR is available on the City’s website and provides the most current information on potable water quality conditions.52
51 Water Acquisitions calculated as (Verified Production – Base FPA) + Makeup Water Obligation 52 City of Adelanto 2024 CCR available at:
https://adelantoca.gov/Documents/Services/Water%20&%20Sewer/Consumer%20Confidence%20Report s/Consumer%20Confidence%20Report%202024.English.pdf?t=202507101838470 Year Water Acquisitions51
2021 1,456
2022 2,039
2023 1,640
2024 1,636
2025 2,364
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While this section focuses on groundwater quality as it pertains to the City’s supply sources, a broader discussion of water quality conditions throughout the Mojave Region, including basin-wide characteristics, regulatory considerations, and regional management issues, is presented in Sub-Chapter 3.1.2 of Regional Chapter 3 – Regional Water Supply Characterization.

Table 7-10 presents a summary of groundwater quality constituents based on information reported in the CSA’s 2024 CCR. The table reflects a subset of reported constituents and has been adapted for clarity and relevance to this UWMP.
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TABLE 7-10: CITY’S POTABLE WATER QUALITY
Water Quality Standards Goal Level Max Level Range Amount Detected Primary Standards
Arsenic (ppb) N/A 10 ND - 2.1 0.08
Fluoride (ppm) N/A 2 ND - 1.4 0.49
Goss Alpha Particle Activity (pCi/L) N/A 15 ND - 6.7 1
Nitrate as N (ppm) N/A 10 ND - 0.50 0.25
Total Chromium (ug/L) N/A 50 0.00 - 0.00 0
Disinfection By-Products
Haloacetic Acid (ug/L) (HAA5) N/A 60 N/A 3.8
Total Trihalomethanes (ug/L) N/A 80 0.2 - 1.40 20.89
Radioactive Contaminants
Gross Alpha (pCi/L) N/A 15 ND - 6.70 1
Secondary Standards
Chloride (ppm) N/A 500 16.0 - 51.0 47
Iron (ug/L) N/A 300 ND - 1000 7.33
Manganese N/A 50 ND - 890 61.35
Odor (units) N/A 3 ND - 1.00 0.36
Specific Conductance (uS/cm) N/A 1600 ND - 800 800
Sulfate (mg/L) N/A 500 ND - 220 220
Total Dissolved Solids (mg/L) N/A 1,000 250 - 650 403
Turbidity N/A 5 ND - 0.59 0.15
Lead and Copper
Lead (ug/L) N/A N/A N/A 0.55
Copper (ug/L) N/A N/A N/A ND
Microbial Contaminants
Total Coliform (# of positive samples) N/A N/A N/A 0
Fecal Coliform or E. Coli (#of positive samples) N/A N/A N/A 0 Federal Unregulated Contaminants
Calcium (mg/L) N/A N/A ND - 25.00 25
Hardness (mg/L) N/A N/A ND - 74.0 74
Magnesium (mg/L) N/A N/A ND - 2.60 2.6
Sodium (mg/L) N/A N/A ND - 140 140
Total Alkalinity (mg/L) (as CaCO3) N/A N/A ND - 75.0 75 520
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7.4.3 Recycled Water Supplies
The City of Adelanto does not currently utilize recycled water within its service area; however, the City continues to evaluate opportunities to develop a recycled water program. Treated effluent generated within the service area is presently managed through discharge to percolation facilities, consistent with existing wastewater operations. Ongoing planning efforts are focused on assessing the feasibility of recycled water production, storage, and distribution infrastructure to support future non-potable uses. Development of recycled water supplies would provide an opportunity to enhance long-term water supply reliability, reduce reliance on groundwater, and support sustainable water management within the community.

7.4.4 Desalination Opportunities
The UWMPA requires urban water suppliers to evaluate potential opportunities for the use of desalinated water, pursuant to CWC Section 10631[i]. Based on current conditions, desalination is not considered a viable supply option for the City due to the absence of suitable source waters and the substantial cost associated with treatment, conveyance, and disposal. Therefore, the City has no plans to develop desalination facilities, and desalinated supplies are not incorporated into the supply projections presented in this sub-chapter.

7.4.5 Water Transfers and Exchanges
The City of Adelanto’s water supply portfolio is primarily managed through groundwater production in accordance with the MBA adjudication, supplemented as needed through replacement and make-up water. In addition to these core supplies, the City has the ability to utilize interconnections with neighboring agencies to support operational flexibility and system reliability.

The City maintains interties with regional partners, including connections that have been utilized to supplement supplies during periods of reduced FPA or operational constraint.

These interties provide an important operational tool for managing short-term supply needs and maintaining system reliability; however, water conveyed through these connections is ultimately derived from the same regional groundwater system and does not represent an independent supply source.

As groundwater demands increase, the City may rely more heavily on supplies conveyed through these interconnections to meet system demands. While these supplies function operationally similar to transfers or exchanges, they are not currently implemented through formalized long-term transfer programs such as permanent BAP transfers. Accordingly, water supplies associated with formal transfers and exchanges are not explicitly assumed in the supply projections presented in this subchapter. The City will continue to evaluate opportunities to utilize interties and other transfer mechanisms, where available, to enhance 521
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operational flexibility and support system reliability during periods of supply constraint or emergency conditions.

7.4.6 Supply Summary
Groundwater serves as the City’s principal water supply source. These supplies, pumped from the Alto Subarea of the MBA, are generally sufficient to meet existing and future demands.

The City’s water supplies are aggregated into the historically managed groundwater system.

Managed groundwater consists of supplies provided through the MBA, including make-up and replacement supplies as well as transfers and exchanges among producers. Under the MBA Judgment, producers in the Alto Subarea are able to meet their water supply requirements through production from the basin’s managed groundwater system. This system incorporates the natural yield of the basin along with supplies made available through regional management actions, including imported water recharge managed by MWA, conservation, water reuse, and transfers of FPA among producers. Consistent with this framework, the City’s total managed groundwater production for the historical period represents the supply available to meet system demands. Total managed groundwater production from 2021 through 2025 is shown in Table 7-11.

TABLE 7-11: CITY’S MANAGED GROUNDWATER PRODUCTION 2021-2025 (AFY) Projected groundwater supplies are derived from the demand projections described in SubChapter 7.5 – Water Use Characterization. Within the adjudicated MBA management framework, the City’s groundwater production adjusts to meet water demands through the managed groundwater system. Accordingly, projected groundwater supplies for the planning horizon are shown in Table 7-12 and Table 7-13.
53 53 The values presented in Table 7-12 and Table 7-13 have been rounded to reflect congruency with the projected demands presented in Sub-Chapter 7.5 – Water Use Characterization.

Year Groundwater Production
2021 4,487
2022 4,640
2023 4,570
2024 4,636
2025 5,044
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TABLE 7-12: CITY’S PROJECTED MANAGED GROUNDWATER SUPPLY 2026 – 2030 (AFY) TABLE 7-13: CITY’S PROJECTED MANAGED GROUNDWATER SUPPLY THROUGH 2050 (AFY) Managed Groundwater Production 2030 2035 2040 2045 2050 Normal 5,555 5,700 5,845 5,990 6,135
Single Dry-Year 5,555 5,700 5,845 5,990 6,135
Multi-Year Drought
Year 1 5,555 5,700 5,845 5,990 6,135
Year 2 5,585 5,730 5,875 6,020 6,165
Year 3 5,615 5,760 5,905 6,050 6,195
Year 4 5,645 5,790 5,935 6,075 6,220
Year 5 5,670 5,815 5,960 6,105 6,250

7.4.7 Delivery System Details
The City’s potable water system conveys groundwater produced from wells located throughout the service area to storage and distribution facilities that deliver water to customers. Extracted groundwater is conveyed to one of the City’s storage reservoirs, which collectively provide approximately 21 million gallons of storage before being distributed through the pressurized potable water system. The distribution system consists of more than 113 miles of pipeline, and approximately 8,880 service connections. The City’s potable water distribution system is shown in Figure 7-2.

Year Type Managed Groundwater Production
Normal 5,455
Single Dry-Year 5,455
Multi-Year Drought
2026 (1st Year) 5,455
2027 (2nd Year) 5,485
2028 (3rd Year) 5,520
2029 (4th Year) 5,550
2030 (5th Year) 5,555
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FIGURE 7-2: POTABLE WATER SYSTEM
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Sub-Chapter 7.5 – Water Use
Characterization
Understanding water use characteristics is essential for the City to reliably and costeffectively manage its water supplies and meet the needs of customers within its service area. This sub-chapter characterizes the City’s retail customer water needs – current and forecast over the next few decades. Characteristics regarding how water use varies amongst different land use classifications, throughout the year, and under differing hydrologic conditions, help to bolster that understanding.

A thorough characterization and analysis provide a realistic prediction of future water use based upon the City’s past and current water use, in addition to considerations of anticipated growth, new regulations, climate change conditions and trends in customer water use behaviors. The analysis presented in this sub-chapter utilizes the water use forecast methodology presented in Sub-Chapter 4.1 of Regional Chapter 4 – Water Use Characterization which examines each water use sector for a variety of factors before aggregating the information into a comprehensive projection of customer water use that becomes the foundation for integration with the City’s water supplies, presented in SubChapter 7.4 – Water Supply and Infrastructure Characterization, to assess long-term water system reliability, presented in Sub-Chapter 7.7 – Water System Reliability and Drought Risk Assessment.

As discussed in Regional Chapter 1 – Introduction, there have been no legislative changes to the UWMPA since the adoption of the City’s 2020 UWMP; however, updates to annual water use reporting have been implemented. These include Urban Water Use Objective (UWUO) reports, and monthly drought and conservation reporting to the Safe and Affordable Funding for Equity and Resilience (SAFER) portal that are consolidated annually into an autogenerated Clearinghouse Annual Inventory Report (CAIR).

This section is organized as follows:
• Current Customer Water Use – This subsection presents actual water use data reflecting the City’s residential and non-residential customers for 2021 through 2025 as well as distribution system losses for this same period. • Compliance with Urban Water Use Objectives and past urban water use efficiency efforts – This subsection documents the derivation of the City’s UWUO, comparison to the City’s actual water use, UWUO reporting process, and past urban water use efficiency efforts, including the City’s 2020 GPCD target. 525
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• Forecasting Customer Use – This subsection presents the derivation and results of future water use forecasts for potable and non-potable water within the City’s service area and estimation of distribution system losses. This subsection also estimates the variations in customer water use the City should expect during years with low rainfall as well as discusses longer-term climate change considerations. • Forecasting Water Use for DRA and Annual Assessment – This subsection focuses on the subset of the customer water use forecast that is necessary for completing the five year Drought Risk Assessment (DRA) and defining the “unconstrained demand” for purposes of the City’s annual water supply and demand assessment. • Projecting Disadvantaged Community Water Use – This subsection presents the estimated water use necessary to meet lower income households, pursuant to CWC Section 10631.1.

7.5.1 Current Customer Water Use
As described in Sub-Chapter 7.2 – Water Service and System Description, the City provides water service to approximately 8,880 service connections within its service area. Under normal operating conditions, customers are served groundwater supplies pumped from wells located throughout the City and treated to meet all applicable state and federal drinking water standards. Information regarding the City’s current customers, recent water use patterns, and expected trends in water demand provides the basis for developing the water use forecasts presented in this 2025 RUWMP. Furthermore, annual records of actual water use provides the basis for determining the City’s compliance with its UWUO, reported annually to DWR beginning in January of 2024.

7.5.1.1 Customer Water Use 2021-2025
Recent customer water use data assists the City in understanding water use trends, effects of any temporary use restrictions imposed during the most recent prolonged drought and recovery from such temporary restrictions, effects of long-term demand management measures, and other pertinent water use factors relevant to its forecast of future water use.

The City is also required to quantify past customer water use pursuant to CWC Section 10631(d)(1). The City records potable water use within five primary categories:
• Single-Family Residential
• Multi-Family Residential
• Commercial and Institutional
• Industrial
• Landscape Irrigation
• Other
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Table 7-14 presents the City’s past customer potable water use by customer classification for 2021–2025 in acre-feet.
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TABLE 7-14: POTABLE CUSTOMER USE 2021-2025 (AF)
Use Category Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total Single-Family
Residential
2021 211 156 159 195 227 231 277 260 250 245 182 190 2,583 2022 175 165 164 207 208 257 244 213 249 207 173 165 2,425 2023 188 141 146 141 246 215 211 265 190 217 181 149 2,291 2024 149 137 141 198 203 252 244 212 223 200 168 149 2,277 2025 219 132 169 161 157 192 291 213 227 199 227 146 2,335 Multi-Family
Residential
2021 21 15 15 18 20 20 23 26 53 24 20 20 274
2022 23 25 37 24 21 11 23 30 29 20 19 20 283
2023 20 11 15 12 22 16 18 24 14 20 17 19 208
2024 14 11 16 21 14 25 24 20 27 32 25 23 250
2025 34 17 25 27 21 29 38 29 25 27 28 24 324
Commercial/
Institutional
2021 33 47 31 48 55 70 74 74 44 68 48 54 646
2022 39 42 47 66 67 46 71 82 87 73 51 56 726
2023 61 29 86 85 139 107 68 87 53 80 46 39 879
2024 42 63 76 44 180 66 94 93 86 97 91 67 999
2025 115 71 86 110 86 100 139 114 112 110 112 64 1,219
Industrial
2021 12 10 11 12 17 17 22 23 26 21 19 16 208
2022 26 19 19 23 22 22 16 26 29 34 9 18 264
2023 36 43 41 33 46 36 30 0 0 32 0 0 299
2024 0 31 16 45 37 42 55 15 15 26 32 18 331
2025 27 11 19 32 11 26 27 27 26 34 26 14 281
Landscape
Irrigation
2021 4 2 3 10 10 7 12 12 13 10 5 3 89
2022 3 4 5 7 11 13 12 12 12 10 4 2 94
2023 98 72 1 3 8 9 9 8 6 112 5 2 334
2024 4 1 1 5 7 11 14 12 11 8 6 2 81
2025 3 2 3 4 6 6 6 12 11 6 8 1 69
Other
2021 0 56 0 15 6 33 5 23 8 7 3 3 159
2022 13 7 3 8 1 3 2 4 12 10 3 3 69
2023 1 0 1 0 92 5 3 6 2 26 7 5 151
2024 1 1 0 2 1 1 0 0 3 1 2 13 26
2025 35 9 2 1 3 0 0 2 2 1 2 1 58
Total Metered
Deliveries
2021 280 287 220 298 336 378 413 418 393 374 277 285 3,959 2022 279 261 275 335 330 352 368 367 418 353 259 263 3,860 2023 404 297 291 275 554 388 339 390 266 487 257 215 4,162 2024 211 243 249 315 441 397 430 352 364 363 324 273 3,964 2025 434 242 305 336 284 353 502 398 404 377 404 249 4,288 528
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The single-family residential and multi-family residential classifications continue to represent the primary components of the City’s water service; however, their relative contribution to total demand has declined in recent years. Historically, residential uses accounted for approximately 75% percent of total potable water demand in 2020, but between 2021 and 2025 this share decreased to approximately 62%. Over the same period, commercial and institutional uses increased modestly from approximately 22% to 25%, while industrial demand, which was previously negligible, accounted for approximately 7% of total use. This shift reflects gradual changes in the City’s economic and land use profile, including incremental growth in commercial and industrial activity, while the overall demand pattern remains broadly consistent with the City’s predominantly residential service area.

7.5.1.2 Existing Distribution System Losses
Distribution system water losses (also known as “real losses”) are the physical water losses from the City’s water distribution system up to the point of delivery to the customer’s system (e.g., up to the residential water meter).

Since 2016, the City has been required to quantify its distribution system losses using the American Water Works Association Method (AWWA).54 An electronic copy of the audit in Excel format is to be submitted to DWR by October 1 of each year for the prior year’s estimated system losses, using DWR’s online submittal tool pursuant to California Code of Regulations (CCR) Section 638.5. Although the AWWA-based audit remains in effect as the primary tool for monitoring distribution system losses, mandated water loss reductions are on the horizon with the SWRCB’s April 1, 2023 adoption of volumetric water loss performance standards.

Pursuant to CCR Section 996, the SWRCB will require suppliers to reduce real loss by January 1, 2028 to no greater than the real water loss standard calculated in its 2027 audit. After 2028, the City shall assess compliance every three years as an average of recent losses.

Additionally, the City will be required to evaluate apparent losses and submit an inventory of apparent losses should average losses exceed the real water loss standard.

Consistent with DWR’s 2025 UWMP guidance, distribution system losses are reported using values submitted through DWR’s Water Loss Audit Program. Table 7-15 summarizes the City’s reported losses for 2021 through 2024. 2025 data was not available at the time this 2025 RUWMP was prepared due to the reporting schedule associated with the AWWA water loss audit process.
54 Title 23 California Code of Regulations Section 638.1 et seq. 529
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TABLE 7-15: DISTRIBUTION SYSTEM LOSS 2021 - 202455
2021 2022 2023 2024

7.3% 15.0% N/A N/A
Average: 11.2%

Due to the dynamic functions of a pressurized potable water distribution system, the estimated annual distribution system loss as a percentage of water entering the system will vary year to year and month to month. On average, however, the City’s distribution system loss represents about 11.2% of water entering the system.

7.5.1.3 Water Loss Control Standard
CWC Section 10608.34 required the SWRCB to develop water loss control and performance standards (Real Water Loss Standards) applicable to urban retail water suppliers. The Real Water Loss Standard for the City was developed using information submitted as part of the City’s annual water loss reporting to the State, specifically for the period 2017 through 2020.

The resulting Real Water Loss Standard is 58.5 gallons per (active and inactive) service connection per day. The resulting Real Water Loss Standard as an average percent of total water supplied is 12.7%. Using the information from the same period, the average “apparent” water loss averaged 3.3% (of total water supplied). The total water loss estimate as a percentage of total water supplied is 16%, although recent AWWA audits discussed above show losses closer to 11.2%.

7.5.2 Compliance with Water Use Targets and
Objectives
This subsection examines the City’s derivation and compliance with state-mandated water use targets and objectives. The Water Conservation Act of 2009, also known as SB X7-7, introduced water conservation targets that served as a valuable measure of progress through 2020 and beyond.

7.5.2.1 Compliance with 2020 Urban Water Use Target
SB X7-7, also known as the Water Conservation Act of 2009, introduced sustainable water use and demand reduction legislation requiring the City to make incremental progress in reducing per capita water use. Specifically, urban water retailers were tasked with achieving 55 Water loss audit data for 2023 and 2024 were not available at the time this 2025 RUWMP was prepared; the City is currently in the process of completing these audits. 530
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a 10% reduction in per capita water use by December 31, 2015, and a 20% reduction by December 31, 2020. Beyond 2020, although reporting on compliance is no longer required, this target remains valuable as a baseline for the City to measure progress on achieving water efficiency goals.

The City’s 2020 GPCD target was established in the 2010 UWMP using the methodology set forth in CWC Section 10608.20(b). The City selected the “20% reduction from baseline” approach (Method 1), which defines the target as 80% of baseline per capita water use calculated over the applicable baseline period. The resulting 2020 target was 192 GPCD.

The City’s calculation of its actual 2020 GPCD utilized the same methodology, in which gross water use represents total potable water supplied to the system, including deliveries, system losses, and authorized unbilled consumption. This total volume, derived from system production records, was divided by the City’s estimated population to calculate per capita water use, resulting in an actual value of 116 GPCD. Because this value was less than the City’s established target, the City was determined to be in compliance with CWC Section 10608.24(b).

Although not required by the UWMPA, in 2025, the City was determined to have an actual GPCD of 103, calculated using the same methodology presented above.

7.5.2.2 Urban Water Use Objective Compliance
In 2018, the California Legislature passed Senate Bill 606 and Assembly Bill 1668, directing the SWRCB to adopt standards to encourage more efficient urban water use. This legislation, known as “Making Conservation a California Way of Life,” was adopted in 2024, establishing individualized UWUO for each urban retail water supplier. In contrast to the SB X7-7 per capita targets, this legislation functions as a water budget tailored to a supplier’s service area, considering residential indoor use, residential and commercial outdoor use based on local evapotranspiration and irrigable landscape area, water loss, and bonus incentives for potable reuse. In addition to the volumetric UWUO, the regulation establishes performance measures for commercial, industrial, and institutional (CII) sectors. The standards become progressively more stringent through 2040. In 2023 and 2025, the City submitted required annual reports to the SWRCB demonstrating that actual water use remained below its calculated UWUO, confirming compliance in 2023 and 2025.

7.5.3 Forecasting Customer Use
Future water use within the City’s service area is projected using a regionally consistent forecasting methodology developed as part of the 2025 RUWMP. As described in SubChapter 4.1.2 Forecasting Regional Water Use of Regional Chapter 4 – Water Use Characterization, this methodology integrates population and land use projections, historical water use trends, and demand management assumptions to estimate future water demands across participating agencies.
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Consistent with this approach, the City’s future water use projections reflect both anticipated changes in customer demand and continued implementation of water use efficiency measures. Forecasts are developed by considering existing customer use characteristics, projected growth in population and service connections, and expected changes in per capita water use over the planning horizon.

The results of this regional forecasting framework, as applied to the City, are presented in the following subsections and corresponding tables.

7.5.3.1 Existing Customer Future Use
Future water use associated with the City’s existing customer base is projected based on current potable water use characteristics and representative GPCD values. As described in Subsection 7.5.2.1, the City’s current GPCD, derived from recent water production and population data, reflects the combined water use of all customer sectors, including both residential and non-residential demands.

The methodology used to develop the representative GPCD value for existing customers is fully described in Sub-Chapter 4.1.2 Forecasting Regional Water Use of Regional Chapter 4 – Water Use Characterization. In general, this approach utilizes total annual potable water production divided by the corresponding service area population to establish a baseline GPCD value representative of current conditions.

For purposes of projecting future demand associated with existing customers, the City has assumed that current water use levels will remain constant over the planning horizon. This assumption reflects observed demand conditions within the City’s service area, where water use has stabilized following prior conservation efforts, regulatory requirements, and longterm demand management measures. As such, existing customer demand is considered “hardened” and no additional reductions in per capita water use have been applied to this customer group.

Accordingly, the City’s existing customer demand is projected to remain at approximately 5,120 acre-feet per year, based on a representative GPCD of 103, for the duration of the planning horizon. Because the representative GPCD is derived from total potable water production, it inherently includes distribution system losses; therefore, no separate adjustment for the City’s representative loss percentage, as described in the prior subsection, has been applied to the existing customer demand projections.

7.5.3.2 New Customer Future Use
Future water use associated with new customers is projected using a regionally consistent forecasting methodology developed as part of the 2025 RUWMP as described in Sub-Chapter

4.1.2 Forecasting Regional Water Use of Regional Chapter 4 – Water Use Characterization.

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estimate incremental demand associated with new development within the City’s service area.

Unlike existing customer demand, which is based on observed production, the new customer forecast is developed by aggregating the individual components of the City’s GPCD to reflect anticipated water use characteristics for future growth and development. These components distinguish between residential indoor and outdoor use, as well as non-residential demands, and are applied to projected population growth to estimate future demand.

For the City, the representative GPCD components applied to new customers are as follows:
• Indoor Residential Use: 47 GPCD
• Outdoor Residential Use: 5 GPCD
• Total Non-Residential Use: 50 GPCD
• Total Use: 102 GPCD
As with the existing customer demand GPCD, the resulting new GPCD represents total potable water production. However, the composition of this GPCD differs for new customers, as residential indoor water use is reduced over time to reflect compliance with applicable UWUO indoor standards, while outdoor residential and non-residential (CII) components are assumed to remain constant. The specific implementation schedule and applicable indoor water use standards are described in Sub-Chapter 4.1.2 Forecasting Regional Water Use of Regional Chapter 4 – Water Use Characterization. Accordingly, the aggregate GPCD applied to new customers declines over the planning horizon as indoor efficiency requirements are incrementally achieved. Because the representative GPCD is based on total potable water production, it inherently includes distribution system losses; therefore, no separate adjustment for the City’s representative loss percentage has been applied to new customer demand projections.

Table 7-16 presents the resulting combined existing and future customer water use forecast, with values rounded to the nearest five acre-feet, which serves as the basis for evaluating the City's ability to meet projected demands under normal and drought conditions as described in Sub-Chapter 7.7 – Water System Reliability and Drought Risk Assessment.

TABLE 7-16: FORECAST FUTURE WATER USE (VALUES IN ACRE-FEET PER YEAR) 2025 2030 2035 2040 2045 2050
5,120 5,555 5,700 5,845 5,990 6,135
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7.5.3.3 Adjusting Water Use Forecasts for Single-Dry and Multiple Dry Conditions
The water use forecast presented in Table 7-16 represents expected water needs under normal climatic conditions. In some regions, adjustments to this forecast may be warranted under drier conditions to reflect increased irrigation resulting from reduced rainfall. However, within the High Desert climate of the RUWMP Planning Area, urban water use is not typically influenced by variations in rainfall. Landscape and agricultural irrigation demands are not dependent on precipitation to meet water needs; therefore, reduced rainfall does not result in increased water use as it might in more temperate or rainfall-dependent regions.

Accordingly, no adjustments have been made to the forecast to account for single dry or multiple dry year conditions. The values presented in Table 7-16 represent unconstrained demand and are assumed to be consistent across all hydrologic year types.56

7.5.3.4 Climate Change Considerations
Incorporating climate change considerations into water use analysis can help inform longterm planning by identifying potential shifts in demand patterns, such as increased landscape irrigation associated with hotter and drier conditions. However, within the High Desert climate of the RUMWP Planning Area, baseline conditions are already characterized by low precipitation and high evapotranspiration rates. As a result, near-term climate change is not expected to materially alter water use behavior or increase demand beyond levels already reflected in existing conditions. Accordingly, no adjustments have been made to the water use forecast to account for climate change. While long-term climate change may incrementally increase evapotranspiration, such effects are expected to be nominal relative to current conditions. The City will continue to evaluate potential climate-related impacts in future UWMP updates and through ongoing regional water planning efforts.

7.5.4 Forecasting Water Use for DRA and Annual
Assessment
This subsection presents the subset of the City’s customer water use forecast that is used to evaluate short-term water supply reliability under drought and operational planning conditions. Specifically, this subsection supports two related but distinct analyses required 56 California Water Code Section 10632(a)(2) states water suppliers should use “unconstrained demand” when performing their annual water supply and demand assessment. This reflects the expected demand prior to implementing shortage response actions as detailed in a Water Shortage Contingency Plan.
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under California Water Code: the five year Drought Risk Assessment (DRA) and the Annual Water Supply and Demand Assessment (Annual Assessment).

The DRA evaluates projected water demand over a five year planning horizon under a sequence of dry conditions to assess potential supply shortfalls. The Annual Assessment, by contrast, is conducted each year and evaluates water supply and demand conditions over a rolling twelve-month period spanning July through June, incorporating both current year conditions and near-term projections. Together, these analyses rely on a consistent representation of “unconstrained demand” derived from the City’s long-term water use forecast presented in the preceding subsections. The following subsections describe the methodology and results used to develop water demand projections for each of these planning efforts.

7.5.4.1 Projecting Water Use for Five Year Drought Risk Assessment
The DRA requires the City to evaluate water supply reliability over a five year planning horizon under a sequence of dry conditions. Consistent with CWC Section 10635 and guidance provided in the 2025 UWMP Guidebook, this assessment is based on a projection of “unconstrained demand” representing anticipated customer water use absent shortage response actions.

For the purposes of the DRA, the City’s projected water demands are derived directly from the long-term water use forecast described in the preceding subsections. This forecast incorporates projected changes in population, service connections, and per capita water use, as well as the effects of ongoing water use efficiency measures and regulatory requirements.

Because the DRA is intended to evaluate baseline system reliability, no additional demand reductions associated with the City’s Water Shortage Contingency Plan (WSCP) are applied.

Projected demands for the DRA are derived from the City's long-term water use forecast developed for the 2025 RUWMP and the City’s retail-specific chapter and are expressed on an annual basis for each of the five years within the planning horizon. No additional adjustments are applied; the annual values reflect the same underlying methodology and assumptions used to develop the five-year planning increment forecasts presented elsewhere in this subchapter. These demand projections reflect total potable water demand, including residential, commercial, institutional, and other customer uses, as well as distribution losses. The demand projections used for the DRA are consistent with those used in the Annual Assessment to ensure alignment in the City’s evaluation of water supply reliability across planning timeframes.

Table 7-17 presents the City’s projected unconstrained water demands for the DRA period (2026-2030), with values rounded to the nearest five acre-feet. These values form the basis for the reliability analysis presented in Sub-Chapter 7.7 – Water System Reliability and Drought Risk Assessment.
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TABLE 7-17: FORECAST DRA WATER USE FOR 2026 THROUGH 2030 (AFY)

7.5.4.2 Projecting Water Use for Annual Assessments
The City conducts an Annual Water Supply and Demand Assessment each year in accordance with CWC requirements. These assessments are prepared and submitted to DWR by July 1 and evaluate anticipated water supply and demand conditions over a rolling twelve-month period spanning July through June.

The City has completed and submitted an Annual Assessment each year since 2022, as required by statute. While the results of these assessments are not included in this UWMP, the methodology and demand assumptions applied are consistent with those presented in this sub-chapter.

7.5.5 Projecting Disadvantaged Community Water Use
Pursuant to CWC Section 10631.1, urban retail water suppliers are required to include projected water use for lower income households in their UWMPs. Per California Health and Safety Code Section 50079.5, a lower income household is defined as one with an income below 80 percent of the area median income, adjusted for family size. For the purposes of the City’s sub-chapter within the 2025 RUWMP, the City’s service area is recognized as a Disadvantaged Community, and median income assumptions are consistent with those presented in Sub-Chapter 2.1.7.2 Economic Trends and Other Social and Demographic Factors of Regional Chapter 2 – The Mojave Region.57 Accordingly, the water use forecast presented in Table 7-17 is inclusive of disadvantaged community water use. 57 California Department of Water Resources, Disadvantaged Communities Mapping Tool, available at:
https://gis.water.ca.gov/app/dacs/
2026 2027 2028 2029 2030
5,455 5,485 5,520 5,550 5,555
536
The City of Adelanto Sub-Chapter 7.6 - Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 7-40
Sub-Chapter 7.6 – Water
Conservation and Shortage
Response
Pursuant to CWC Sections 10631(e) and 10632, this sub-chapter summarizes the City's demand management measures and water shortage response framework. These efforts support efficient use of available water supplies and provide the foundation for managing water use under both normal and shortage conditions.

The City has historically implemented a range of demand management measures aimed at improving water use efficiency, reducing long-term demand, and supporting compliance with applicable State requirements. These measures include ongoing programs, policies, and regional coordination efforts designed to manage existing customer use and guide future water use patterns.

This sub-chapter also highlights key components of the City’s Water Shortage Contingency Plan (WSCP), including shortage levels, response actions, monitoring procedures, and communication strategies. The WSCP establishes the framework through which the City evaluates water supply conditions and implements staged response actions during periods of constrained supply. No substantive changes have been made to the City’s 2020 WSCP, and the shortage levels, response actions, monitoring procedures, and communication protocols described therein remain applicable; however, water supply reliability information has been updated and is presented in the 2025 RUWMP and this chapter, reflecting current data, assumptions, and planning conditions.

A complete description of the City’s WSCP, including detailed implementation procedures and supporting documentation, is provided in Appendix 7a.

7.6.1 Demand Management Measures
The City has implemented a comprehensive set of demand management measures (DMMs) to promote the efficient use of water and support long-term water supply reliability. These measures are consistent with the requirements of CWC Section 10631(e) and are designed to reduce water use, improve system efficiency, and support compliance with State water use objectives.
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The City of Adelanto Sub-Chapter 7.6 - Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 7-41
The City is a member of the Alliance for Water Awareness and Conservation (AWAC), a regional partnership of water agencies within the Mojave Water Agency service area focused on promoting water conservation, public outreach, and coordination of demand management efforts. Through its participation in AWAC and collaboration with regional partners, the City leverages shared resources and consistent messaging to enhance the effectiveness of its conservation programs.

The City will continue to implement and refine its DMMs to support efficient water use and meet applicable regulatory requirements. Additional information regarding recent and planned demand management activities is provided in the following subsections.

7.6.2 Foundational Demand Management Measures
The City’s foundational DMMs remain unchanged from the 2020 UWMP and continue to serve as the basis for ongoing water conservation efforts. These measures include water waste prevention ordinances, metering, conservation-based rate structures, public education and outreach, programs to assess and manage distribution system losses, and coordination of conservation program implementation.

Water Waste Prevention Ordinances
The City has adopted water conservation regulations through its Municipal Code, which establish prohibitions on water waste and define enforcement mechanisms to address noncompliant uses. These regulations provide a baseline level of conservation that is in effect at all times and may be expanded during declared shortage conditions.

Metering
The City meters all potable water service connections, enabling accurate measurement of water use and supporting volumetric billing. Metering provides the foundation for tracking consumption patterns, identifying inefficiencies, and implementing effective conservation programs.

Conservation Pricing
The City utilizes a tiered rate structure designed to encourage efficient water use by increasing the marginal cost of water at higher levels of consumption. This pricing approach supports long-term demand management by incentivizing conservation across all customer classes.

Public Education and Outreach
The City implements public education and outreach efforts to promote water conservation and increase customer awareness of efficient water use practices. These efforts include dissemination of conservation materials and coordination with regional programs to support consistent messaging.
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The City of Adelanto Sub-Chapter 7.6 - Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 7-42
Programs to Assess and Manage Distribution System Losses The City conducts regular water loss audits in accordance with AWWA methodologies to quantify and manage systems losses. These efforts support ongoing maintenance, leak detection, and system improvements to enhance overall water use efficiency.

Conservation Program Coordination and Staffing Support
The City supports the implementation of DMMs through coordination with regional partners and internal staff resources. This approach allows the City to leverage available programs and funding opportunities while maintaining effective administration of local conservation efforts.

Other Demand Management Measures
The City has adopted additional measures, including landscape water conservation requirements consistent with the Model Water Efficient Landscape Ordinance (MWELO). These measures support long-term reductions in outdoor water use and promote efficient landscape design and irrigation practices.

7.6.2.1 Recent DMM Activities
The City has continued to implement DMMs focused on improving system efficiency, reducing potable water demands, and supporting long-term water conservation. Recent activities include upgrading the City’s customer water metering system to an advanced metering infrastructure (AMI) system, which will improve the City’s ability to track customer water use, identify abnormal consumption patterns, and support more effective customer service and conservation messaging. The AMI project is currently underway and is anticipated to be completed in summer 2026.

The City has also advanced efforts to reduce portable water use at its wastewater treatment plant by converting the plant’s internal water system to use treated effluent. This project is expected to eliminate potable water demand associated with certain plant operations and is anticipated to be completed in spring 2026. Together, these activities support the City’s broader efforts to improve water use efficiency, reduce system demands, and make more effective use of available local water resources.

7.6.2.2 Planned DMM Activities
The City will continue to implement and refine its existing DMMs to support efficient water use and compliance with applicable State requirements. Planned activities include continued implementation of the AMI system, use of improved metering data to support customer outreach and system management, and ongoing evaluation of opportunities to reduce potable water use where feasible.
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The City of Adelanto Sub-Chapter 7.6 - Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 7-43
The City is also studying the feasibility of developing Title 22 recycled water supplies for community use. This effort is intended to evaluate potential opportunities for beneficial reuse of treated effluent, including future non-potable applications that could offset portable demands and enhance long-term water supply reliability. The City will continue to assess the technical, regulatory, and financial feasibility of recycled water implementation as part of its broader demand management and water supply planning efforts.

7.6.3 Water Shortage Contingency Plan
The City has adopted a Water Shortage Contingency Plan (WSCP) in accordance with CWC Section 10632. The WSCP establishes a structured framework for managing water supply shortages through defined shortages levels, corresponding response actions, and ongoing monitoring of water supply and demand conditions. The WSCP is designed to ensure that the City can respond effectively to a range of water shortage conditions, from minor supply constraints to more severe drought scenarios. The plan identifies stages of water shortage based on severity of supply conditions and outlines the actions the City may implement to reduce demand, manage available supplies, and maintain essential public health and safety services.

The WSCP also incorporates procedures for evaluating water supply reliability, including coordination with the City’s Annual Water Supply and Demand Assessment, which serves as the primary mechanism for identifying and responding to changing water supply conditions on an ongoing basis. Public communication and outreach are integral components of the WSCP and are used to inform customers of water supply conditions, required conservation actions, and applicable restrictions during shortage events. The following subsections summarize key components of the City’s WSCP, including shortage levels, response actions, and monitoring and implementation procedures.

7.6.3.1 Summary of Water Shortage Levels and Response
Actions
The City’s WSCP establishes a series of defined water shortage levels that correspond to increasing degrees of supply constraint, associated demand reduction targets, and specific response actions. This staged framework enables the City to implement proportional measures to manage water use and maintain essential public health and safety services during periods of reduced supply. The WSCP includes six shortage levels, each associated with a targeted reduction in water use relative to normal conditions. As shortage conditions intensify, the City may implement progressively more restrictive measures to reduce demand and manage available supplies. The general framework of shortage levels and representative response actions is summarized below:
• Stage 1 – Up to 10% Shortage
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The City of Adelanto Sub-Chapter 7.6 - Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 7-44
Minor shortage conditions prompt voluntary conservation and public awareness measures to reduce discretionary water use.
• Stage 2 – Up to 20% Shortage:

Moderate shortage conditions require additional conservation measures and increased enforcement of water waste restrictions.
• Stage 3 – Up to 30% Shortage:

Significant shortage conditions result in expanded restrictions on outdoor irrigation and other non-essential water uses.
• Stage 4 – Up to 40% Shortage:

Severe shortage conditions result in expanded restrictions on outdoor irrigation and other non-essential water uses.
• Stage 5 - Up to 50% Shortage:

Critical shortage conditions require strict limitations on water use with prioritization of essential public health and safety needs.
• Stage 6 – Greater than 50% Shortage
Emergency shortage conditions trigger maximum conservation actions, including suspension of non-essential water uses.

As water supply conditions change, the City may transition between shortage levels based on ongoing evaluation of supply availability, customer demand, and system conditions.

7.6.3.2 Summary of Monitoring Procedures and
Implementation
The City’s WSCP includes procedures for monitoring water supply and demand conditions and implementing appropriate response actions based on observed and anticipated conditions. These procedures are intended to ensure that shortage response actions are timely and commensurate with the severity of supply constraints. The City evaluates water supply reliability each year through its Annual Assessment, which considers local water supplies, unconstrained demand, planned water use, infrastructure conditions, and current year and assumed dry year scenarios to determine whether implementation of a water shortage level is warranted. The City’s Annual Assessment serves as the primary mechanism for evaluating near-term supply reliability and informing implementation of shortage response actions. Under the WSCP, the City evaluates available supply and anticipated demand on or before June 1 of each year, and if a current or expected shortage level is identified, the City Council may trigger the appropriate response actions through resolution. 541
The City of Adelanto Sub-Chapter 7.6 - Water Conservation and Shortage Response 2025 Mojave RUWMP – Public Draft 7-45
Additional detail regarding the Annual Assessment is provided in Subsection 7.5.4 Forecasting Water Use for DRA and Annual Assessment of Sub-Chapter 7.5 – Water Use Characterization.

Implementation of the WSCP includes coordination among City staff and communication with customers and regional partners. The City monitors production data, customer demand, and system conditions on an ongoing basis, with reporting intensity increasing as shortage levels escalate, and uses this information to evaluate the effectiveness of response actions and determine whether modifications, escalation, or termination of shortage stages are necessary.
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The City of Adelanto Sub-Chapter 7.7 - Water System Reliability and Drought Risk Assessment 2025 Mojave RUWMP – Public Draft 7-46
Sub-Chapter 7.7 – Water System
Reliability and Drought Risk
Assessment
This sub-chapter evaluates the reliability of the City’s water supplies to meet projected demands under a range of hydrologic conditions, consistent with CWC Sections 10631 (c) and 10635. The analysis integrates the water supply characterization presented in Sub-Chapter

7.4 – Water Supply and Infrastructure Characterization with the water use projections developed in Sub-Chapter 7.5 – Water Use Characterization to assess the City’s ability to meet customer demands during normal, single dry, and multiple dry year conditions.

The reliability analysis considers the availability of the City’s water supplies, including groundwater production and supplemental supplies, in relation to projected customer demands over the planning horizon. This evaluation is intended to identify potential supply shortfalls and assess the City’s capacity to maintain reliable water service under varying conditions. In addition to the long-term reliability analysis, this sub-chapter incorporates the City’s Drought Risk Assessment, which evaluates water supply reliability over a five-year planning horizon under a sequence of dry conditions.

The results of this analysis provide the basis for evaluating the City’s water supply reliability and inform the implementation of the City’s WSCP, as described in Sub-Chapter 7.6 – Water Conservation and Shortage Response.

7.7.1 Five Year Drought Risk Assessment
The DRA evaluates the City’s ability to meet projected water demands over a five-year planning horizon under a sequence of dry conditions. This assessment provides a forwardlooking evaluation of water supply reliability and is intended to identify potential supplydemand imbalances under extended drought scenarios. Projected water demands for the DRA as based on the City’s unconstrained demand forecast described in Sub-Chapter 7.5 – Water Use Characterization and are expressed on an annual basis over the five-year planning period. These demands reflect anticipated customer use absent implementation of shortage response actions.

Available water supplies are evaluated based on the City’s managed groundwater supplies, which include groundwater production, replacement water, and make-up water, as described in Sub-Chapter 7.4 – Water Supply and Infrastructure Characterization. Under the 543
The City of Adelanto Sub-Chapter 7.7 - Water System Reliability and Drought Risk Assessment 2025 Mojave RUWMP – Public Draft 7-47
terms of the MBA adjudication, the City has discretion in managing its groundwater production and associated supplemental supplies, allowing it to adjust its supply portfolio to meet projected demands during dry conditions.

The DRA compares projected water demands to available supplies to evaluate the City’s capacity to meet customer needs over the five-year period. Table 7-18 presents the results of this analysis, including projected demands, available supplies, and any resulting surplus or shortage for each year of the DRA planning horizon, with values rounded to the nearest five acre-feet.

TABLE 7-18: FIVE YEAR DROUGHT RISK ASSESSMENT (AFY)
2026 2027 2028 2029 2030
Supply 5,455 5,485 5,520 5,550 5,555
Demand 5,455 5,485 5,520 5,550 5,555
Difference 0 0 0 0 0

7.7.2 Long Term Service Reliability
The UWMPA directs urban water purveyors to analyze water supply reliability in a normal, single dry, and five consecutive dry years over a 20-year planning horizon. The 2025 UWMP Guidebook recommends extending that period to twenty-five (25) years to provide a guiding document for future land use and water supply planning through the next UWMP cycle. The City’s long-term service reliability reflects the recommended 25-year planning horizon anticipating a normal, single dry, and five consecutive dry years from 2025 – 2050.

7.7.2.1 Normal and Single Dry Conditions 2030 – 2050
The following analysis evaluates the City’s availability to meet projected water demands under normal and single dry year conditions for the 2030 through 2050 planning horizon. This evaluation compares available water supplies to projected customer demands to assess the City’s capacity to reliably meet water needs under varying hydrologic conditions. Under both normal and single dry year conditions, the City’s supplies are managed within the framework of the MBA adjudication, which provides flexibility in balancing groundwater production and supplemental supplies. As a result, available supplies are sufficient to meet projected demands throughout the planning horizon.

Table 7-19 presents the results of the normal and single dry year reliability analyses, including projected demands, available supplies, and resulting surplus or shortage for each timestep from 2030 through 2050. Values are rounded to the nearest five acre-feet. 544
The City of Adelanto Sub-Chapter 7.7 - Water System Reliability and Drought Risk Assessment 2025 Mojave RUWMP – Public Draft 7-48
TABLE 7-19: NORMAL AND SINGLE DRY YEAR WATER SUPPLY AND DEMAND THROUGH 2050 (AFY) Normal Year 2030 2035 2040 2045 2050
Supply 5,555 5,700 5,845 5,990 6,135
Demand 5,555 5,700 5,845 5,990 6,135
Difference 0 0 0 0 0
Single Dry Year 2030 2035 2040 2045 2050
Supply 5,555 5,700 5,845 5,990 6,135
Demand 5,555 5,700 5,845 5,990 6,135
Difference 0 0 0 0 0

7.7.2.2 Five Consecutive Dry Years 2030 – 2050
The following analysis evaluates the City’s ability to meet projected water demands over a five-year period of consecutive dry conditions for the 2030 through 2050 planning horizon.

This assessment provides a more conservative evaluation of water supply reliability by examining the potential effects of extended drought conditions on available supplies. Under multiple dry year conditions, the City continues to manage its supplies within the framework of the MBA adjudication, which allows for flexibility in balancing groundwater production and supplemental supplies. This managed approach enables the City to adjust its supply portfolio over time to meet projected demands, even during extended periods of drought.

Table 7-20 presents the results of the multiple dry year reliability analysis, including projected demands, available supplies, and any resulting surplus or shortage for each year of the fiveyear dry sequence. Values are rounded to the nearest five acre-feet.

Together, the available supplies, when paired against projected demand conditions, demonstrate that the City has sufficient supplies to meet water demands under five consecutive dry year conditions through 2050.
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The City of Adelanto Sub-Chapter 7.7 - Water System Reliability and Drought Risk Assessment 2025 Mojave RUWMP – Public Draft 7-49
TABLE 7-20: FIVE CONSECUTIVE DRY YEARS WATER SUPPLY AND DEMAND THROUGH 2050 (AFY) 2030 2035 2040 2045 2050
Year 1
Supply 5,555 5,700 5,845 5,990 6,135
Demand 5,555 5,700 5,845 5,990 6,135
Difference 0 0 0 0 0
Year 2
Supply 5,585 5,730 5,875 6,020 6,165
Demand 5,585 5,730 5,875 6,020 6,165
Difference 0 0 0 0 0
Year 3
Supply 5,615 5,760 5,905 6,050 6,195
Demand 5,615 5,760 5,905 6,050 6,195
Difference 0 0 0 0 0
Year 4
Supply 5,645 5,790 5,935 6,075 6,220
Demand 5,645 5,790 5,935 6,075 6,220
Difference 0 0 0 0 0
Year 5
Supply 5,670 5,815 5,960 6,105 6,250
Demand 5,670 5,815 5,960 6,105 6,250
Difference 0 0 0 0 0

7.7.3 Annual Reliability Assessment
Each year, the City considers current supply and demand conditions and performs an Annual Water Supply and Demand Assessment pursuant to CWC Section 10632.1 to evaluate real time or near-term circumstances that are different than the DRA scenario. This assessment evaluates actual current water supply and use conditions for a prescribed 12-month forecast (July through the following June). Procedures for conducting the Annual Assessment are contained in the City’s Water Shortage Contingency Plan. The City has conducted the assessment as required by the CWC and will continue this planning exercise to provide a reliability assessment for then-current conditions regarding supplies and expected (unconstrained) demands.
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The City of Adelanto Sub-Chapter 7.7 - Water System Reliability and Drought Risk Assessment 2025 Mojave RUWMP – Public Draft 7-50

7.7.4 Water Supply Reliability Summary
The City’s water supply portfolio is capable of meeting the water uses in its service area in normal, single dry, and five consecutive dry years from 2025 through 2050. 547
The City of Adelanto Sub-Chapter 7.8 – Energy Intensity Analysis 2025 Mojave RUWMP – Public Draft 7-51
Sub-Chapter 7.8 – Energy Intensity
Analysis
Pursuant to CWC Section 10631.2, the City evaluates the energy intensity of its water supply and distribution system. Entergy intensity is defined as the amount of energy used to extract, treat, and deliver water to customers and is typically expressed in kilowatt-hours per acrefoot (kWh/AF). The City’s water supply portfolio is primarily comprised of locally produced groundwater. As a result, energy use is largely associated with groundwater extraction and distribution within the City’s service area, rather than long-distance conveyance or advanced treatment processes.

The City continues to monitor energy use associated with its water system operations and will evaluate opportunities to improve operational efficiency where feasible. Total energy intensity is reported in Table 7-21.

TABLE 7-21: ENERGY INTENSITY – TOTAL UTILITY APPROACH FOR DEC 2024 THROUGH DEC 2025 Sum of All Water Management Processes
Volume of Water Entering Process (acre-feet) 5,445
Energy Consumed (kWh) 452,615
Energy Intensity (kWh/acre-foot) 83
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2025 Mojave RUWMP – Public Draft 8-1
Chapter 8.0 COUNTY SERVICE AREA
64 SPRING VALLEY LAKE
This page is reserved for Chapter 8 – County Service Area 64 Spring Valley Lake. The complete County Service Area 64 Spring Valley Lake retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by the County of San Bernardino. 549
2025 Mojave RUWMP – Public Draft 9-1
Chapter 9.0 COUNTY SERVICE AREA
70J OAK HILLS
This page is reserved for Chapter 9 – County Service Area 70J Oak Hills. The complete County Service Area 70J Oak Hills retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by the County of San Bernardino. 550
2025 Mojave RUWMP – Public Draft 10-1
Chapter 10.0 GOLDEN STATE WATER
COMPANY –BARSTOW SYSTEM
This page is reserved for Chapter 10 – Golden State Water Company – Barstow System. The complete Golden State Water Company – Barstow System retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by the Golden State Water Company.
551
2025 Mojave RUWMP – Public Draft 11-1
Chapter 11.0 HESPERIA WATER

DISTRICT
This page is reserved for Chapter 11 – Hesperia Water District. The complete Hesperia Water District retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by the City of Hesperia.
552
2025 Mojave RUWMP – Public Draft 12-1
Chapter 12.0 HI-DESERT WATER

DISTRICT
This page is reserved for Chapter 12 – Hi-Desert Water District. The complete Hi-Desert Water District retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by Hi-Desert Water District.
553
2025 Mojave RUWMP – Public Draft 13-1
Chapter 13.0 JOSHUA BASIN WATER

DISTRICT
This page is reserved for Chapter 13 – Joshua Basin Water District. The complete Joshua Basin Water District retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by Joshua Basin Water District.
554
2025 Mojave RUWMP – Public Draft 14-1
Chapter 14.0 LIBERTY UTILITIES – APPLE
VALLEY
This page is reserved for Chapter 14 – Liberty Utilities – Apple Valley. The complete Liberty Utilities – Apple Valley retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by Liberty Utilities – Apple Valley. 555
2025 Mojave RUWMP – Public Draft 15-1
Chapter 15.0 PHELAN PIÑON HILLS

COMMUNITY SERVICES DISTRICT
This page is reserved for Chapter 15 – Phelan Piñon Hills Community Services District. The complete Phelan Piñon Hills Community Services District retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by Phelan Piñon Hills Community Services District.
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2025 Mojave RUWMP – Public Draft 16-1
Chapter 16.0 VICTORVILLE WATER

DISTRICT
This page is reserved for Chapter 16 – Victorville Water District. The complete Victorville Water District retail specific chapter is included in the full 2025 Mojave RUWMP and is adopted separately by the City of Victorville.
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2025 Mojave RUWMP – Public Draft A-1
APPENDIX 1 – NOTICES
558
August 27, 2025
Notice of Intent to Prepare a Regional Urban Water Management Plan for the Mojave Region This notice is to inform you that the urban water suppliers within the greater Mojave region are preparing a 2025 Regional Urban Water Management Plan (UWMP) pursuant to the California Water Code (CWC). All wholesale and retail urban water suppliers serving more than 3,000 customer connections are required to prepare an UWMP every five (5) years. The following urban water suppliers are collectively preparing this Regional UWMP:

City of Adelanto Water District
County Service Area 64
County Service Area 70 J
Helendale Community Services District
Hesperia Water District
Hi-Desert Water District
Golden State Water Company – Barstow System
Joshua Basin Water District
Liberty Utilities – Apple Valley Water Company
Mojave Water Agency
Phelan Piñon Hills Community Services District
Victorville Water District
The purpose of a Regional UWMP is to allow the urban water suppliers to coordinate and efficiently address the State’s requirements as mandated in the CWC through a regional representation of water supply reliability. While the Regional UWMP will provide overarching and consistent information on water supplier reliability, each urban retail supplier will also update its unique Water Shortage Contingency Plan (WSCP), tailored to its specific service area and operations. Each urban supplier will separately adopt the Regional UWMP and its unique WSCP by July 1, 2026.

In accordance with CWC Section 10642, which encourages “active involvement of diverse social, cultural, and economic elements of the populations” in preparing a UWMP, the public will, at a minimum, have the opportunity to participate in the planning process through public hearings anticipated to occur in April or May of 2026 as part of each urban supplier’s adoption process. A draft copy of the 2025 Regional UWMP will be made available for review prior to hearings, providing an opportunity for (1) Community input regarding water supply reliability; (2) Consideration of the economic impacts of complying with CWC status governing the Regional UWMP; and (3) Discussion of each agency’s WSCP.

Detailed information, including contacts for each agency, future public hearing notices, schedules, and draft plan materials, will be available at the Mojave Water Agency’s website at https://www.mojavewater.org/basin-management/regional-planning/urban-water-managementplan/, or at similar links hosted by each urban retail water supplier.

Questions regarding this notice or the 2025 Regional UWMP process may be directed to the appropriate retail agency using the contact information found on the website. 559

The urban water suppliers participating in the 2025 RUWMP, along with their respective public hearing dates and proposed dates to consider adoption, are presented in Table 1. 560
TABLE 1: PARTICIPATING AGENCIES AND HEARING INFORMATION Agency Public Hearing Adoption
Hesperia Water District June 2nd 2026
Hi-Desert Water District June 3rd 2026
Joshua Basin Water District June 3rd 2026
Golden State Water Company - Barstow May 27th 2026
Liberty Utilities - Apple Valley June 4th 2026
San Bernardino County Service Area 64 June 23rd 2026
San Bernardino County Service Area 70J June 23rd 2026
Phelan Pinion Hills CSD June 10th 2026
City of Adelanto Water District June 10th 2026
Mojave Water Agency June 11th 2026
Victorville Water District June 16th 2026
Each participating agency will hold its own public hearing to consider adoption of the 2025 RUWMP as it applies to its service area, including the applicable regional chapters, its respective retailerspecific chapter, its WSCP and all applicable appendices. MWA will separately consider adoption of the entirety of the 2025 RUWMP and its WSCP.

Hesperia Water District
The Hesperia Water District will hold a public hearing as follows:

Date: May 19, 2026
Time: 6:30 PM
Location: City Council Chambers 9700 Seventh Ave., Hesperia CA, 92345 Copies of the draft 2025 RUWMP, including the Hesperia Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at 9700 Seventh Ave., Hesperia CA, 92345 during regular business hours and online at https://hesperia.legistar.com/Calendar.aspx
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Hi-Desert Water District
The Hi-Desert Water District will hold a public hearing as follows:

Date: June 4, 2026
Time: 9:00 AM
Location: https://teams.microsoft.com/meet/284381397435981?p=HKnYB1DhSKyacIZB6S Passcode: uc3Ee7km
Copies of the draft 2025 RUWMP, including the Liberty Utilities – Apple Valley retailer-specific chapter and Liberty Utilities – Apple Valley WSCP and applicable appendices, will be available for public review online at https://libertyutilities.com/
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San Bernardino County Service Area 64
The San Bernardino County Service Area 64 will hold a public hearing as follows:

Date: June 23, 2026
Time: 10:00 AM
Location: 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 Copies of the draft 2025 RUWMP, including the San Bernardino County Service Area 70J retailerspecific chapter and the CSA’s WSCP and applicable appendices, will be available for public review at 385 North Arrowhead Avenue, First Floor, San Bernardino, CA, 92415 during regular business hours and online at https://sanbernardino.legistar.com/Calendar.aspx Phelan Pinion Hills Community Services District
The Phelan Pinion Hills Community Services District will hold a public hearing as follows:

Date: June 10, 2026
Time: 5:00 PM
Location: 4176 Warbler Road, Phelan, CA 92371
Copies of the draft 2025 RUWMP, including the Phelan Pinion Hills Community Services District retailer-specific chapter and the CSD’s WSCP and applicable appendices, will be available for public review at 4176 Warbler Road, Phelan, CA 92371 during regular business hours and online at www.pphcsd.org
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City of Adelanto Water District
The City of Adelanto Water District will hold a public hearing as follows:

Date: June 16, 2026
Time: 6:00 PM
Location: City Hall 14343 Civic Drive Victorville, CA 92392 Copies of the draft 2025 RUWMP, including the Victorville Water District retailer-specific chapter and the District’s WSCP and applicable appendices, will be available for public review at City Hall 14343 Civic Drive Victorville, CA 92392 during regular business hours and online at https://www.victorvilleca.gov/Government/City-Departments/City-Clerk/Agendas-MeetingsMinutes 564
NOTICE IS HEREBY GIVEN that the Mojave Water Agency
(MWA) and the ten urban water suppliers participating in the 2025 Mojave Regional Urban Water Management Plan
(2025 RUWMP), as listed below, will hold public hearings to receive comments on the proposed 2025 RUWMP, including each participating agency’s specific chapter contained within the 2025 RUWMP and each agency’s Water Shortage
Contingency Plan (WSCP). The 2025 RUWMP is a regional
planning document prepared collaboratively by MWA and
participating urban water suppliers within the Mojave
Region in accordance with the California Urban Water
Management Planning Act.