Turlock City Council
May 26, 2026

Executive Summary

N-C-693-20-16-01-WP-Task 20-2025 UWMP
ES-4 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

new surface water source from SRWA and its updated municipal code . As SRWA recently developed its WSCP in 2024 during preparation of its 2020 UWMP, the SRWA’s WSCP did not require revisions.

Turlock’s updated WSCP was adopted as a separate document concurrently with this plan, by separate resolution, to allow for updates to be made outside of the UWMP preparation process. SRWA’s WSCP was adopted concurrently with its 2020 UWMP, by separate resolution.

UWMP PREPARATION, REVIEW, AND ADOPTION
Turlock and SRWA prepared this Joint 2025 UWMP in coordination with the public. While preparing this plan, Turlock and SRWA also notified other stakeholders of its preparation, its availability for review, and the public hearing prior to adoption.

Turlock and SRWA encouraged community participation in the development of the Joint 2025 UWMP and Turlock’s WSCP using mailings and the City and SRWA’s website. These public notices included the times and places of the public hearings, as well as where the plans would be available for public inspection. The public hearings provided opportunities for Turlock and SRWA’s water users and the general public to become familiar with the Joint 2025 UWMP, including the WSCPs, and ask questions about their plans for continuing to provide reliable, safe, high-quality water and mitigating potential water shortages.

Following the public hearing s, the Joint 2025 UWMP and Turlock’s WSCP Update were adopted by the SRWA Board of Directors on MM DD, 2026, and adopted by the Turlock City Council on MM DD, 2026. A copy of the adopted Joint 2025 UWMP, including the WSCPs, was submitted to the California Department of Water Resources and to the California State Library. An electronic copy of th e adopted Joint 2025 UWMP and Turlock’s WSCP Update will also be available on the SRWA and Turlock websites.

N-C-693-20-16-01-WP-Task 20-2025 UWMP
1-1 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Introduction
This chapter provides an introduction and overview of the Stanislaus Regional Water Authority (SRWA) and City of Turlock ( Turlock) J oint 2025 Urban Water Management Plan (UWMP), including the importance and extent of SRWA and Turlock’s water management planning efforts, changes since the preparation of SRWA and Turlock’s 2020 UWMPs, and the organization of the Joint 2025 UWMP. This 2025 UWMP has been prepared jointly by SRWA, City of Turlock, and West Yost.

1.1 INTRODUCTION
The Urban Water Management Planning Act (Act) was originally established by Assembly Bill (AB) 797 on September 21, 1983. Passage of the Act was recognition by State legislators that water is a limited resource and a declaration that efficient water use an d conservation would be actively pursued throughout the State. The primary objective of the Act is to direct “urban water suppliers” to develop a UWMP which provides a framework for long -term water supply planning, and documents how urban water suppliers a re carrying out their long -term resource planning responsibilities to ensure adequate water supplies are available to meet existing and future water demands. A copy of the current version of the Act, as incorporated in Sections 10608 and Sections 10610 thr ough 10656 of the California Water Code (CWC), is provided in Appendix A of this plan.

1.2 IMPORTANCE AND EXTENT OF WATER MANAGEMENT PLANNING EFFORTS The purpose of the UWMP is to provide a planning tool for SRWA and Turlock for developing, managing, and delivering municipal water supplies to the Cities of Ceres’ and Turlock’s water service areas. This Joint UWMP provides SRWA and Turlock with a water management action plan for guidance as water demand and/or water supply conditions change.

Water Shortage Contingency Plans (WSCPs) for both SRWA and Turlock are included in this UWMP and provide plans for response to various water supply shortage conditions. SRWA’s WSCP was adopted in October 2024 and the updated WSCP for Turlock was adopted MM DD, 2026 in parallel with this UWMP.

1.3 CHANGES FROM 2020 UWMP
The Urban Water Management Planning Act has been modified over the years in response to the State’s water shortages, droughts and other factors. A significant amendment was made in 2009, after the 2007 to 2009 drought, and as a result of the Governor’s call for a statewide 20 percent reduction in urban water use by the year 2020. This mandated water use reduction was included in the Water Conservation Act of 2009, also known as Senate Bill Seven of the Senate’s Seventh Extraordinary Session of 2009 (SB X7-7). This Act required agencies to establish water use targets for 2020 that would result in statewide water savings of 20 percent by 2020. Turlock is required to report compliance with its 2020 water use target in its 2025 UWMP. This compliance reporting is not applicable to SRWA since it is not a retail water agency.

The 2012 to 2016 drought led to further amendments to the CWC to improve on water supply planning for long -term reliability and resilience to drought and climate change. The 2018 Water Conservation Regulation for Making Conservation a California Way of Life (AB 1668 [Friedman] and SB 606 [Hertzberg]) required major additions and changes to the CWC. These changes are associated with managing drought preparedness and water shortage contingency planning for urban water suppliers.

Chapter 1
Introduction

N-C-693-20-16-01-WP-Task 20-2025 UWMP
1-2 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

No substantive changes to the requirements have been adopted since the completion of SRWA and Turlock’s 2020 UWMPs. This Joint 2025 UWMP builds on the planning and reporting provided in SRWA and Turlock’s 2020 UWMPs. Key updates include:

1. Water Supply Reliability Assessment – a water supply and demand assessment which compares the total water supply sources available to SRWA and Turlock with the long-term total projected water use over the next 25 years (to 2050), in five-year increments, for a normal water year, a single dry water year, and a drought lasting five consecutive water years (CWC §10635(a))

2. Drought Risk Assessment – an assessment of SRWA’s and Turlock’s water supply reliability assuming that the Years 2026 to 2030 will be the five dry consecutive years (CWC §10635(b))

3. Water Use Target Compliance – compliance with Turlock’s previously adopted 2020 per capita water use targets in accordance with SB X7-7 (Water Conservation Act of 2009, SB X7-7; CWC §10608.20)

4. Water Loss Quantification – a summary report quantifying Turlock’s retail system water loss for Years 2021 to 2025, and indicating compliance with Turlock’s distribution loss standard as established by the State Water Resources Control Board (State Water Board) (CWC §10631(d)(3)(c))

5. Groundwater Management Compliance – status update on Sustainable Groundwater Management Act (SGMA) compliance activities (i.e., status of Groundwater Sustainability Agency (GSA) activities and Groundwater Sustainability Plan (GSP) implementation) (CWC §10631(b)(4))
Because SRWA’s 2020 UWMP and WSCP were completed in October 2024 (as SRWA began delivering water to its customers in November 2023), SRWA’s WSCP will not be updated in parallel with the Joint 2025 UWMP.

Turlock’s WSCP was previously adopted in May 2021 concurrent with its 2020 UWMP. This Joint 2025 UWMP includes updates and refinements to Turlock’s WSCP to incorporate the new SRWA water supply source and provisions in its updated municipal code.

1.4 PLAN ORGANIZATION
This Joint 2025 UWMP contains the appropriate sections and tables required per CWC Division 6, Part 2.6 (Urban Water Management Planning Act), included in Appendix A of this 2025 UWMP, and has been prepared based on guidance provided by the California Depa rtment of Water Resources (DWR) in its 2025 Urban Water Management Plan Guidebook for Urban Water Suppliers (DWR Guidebook).

As described in this plan, SRWA is a wholesale water supplier that delivers treated surface water to the Cities of Turlock and Ceres (Cities). Therefore, where applicable, separate descriptions have been included for the SRWA and City of Turlock water systems. These sections reference each other extensively. Because SRWA does not have any direct urban customers, the Cities oversee demand management measures and other public outreach activities.

Chapter 1
Introduction

N-C-693-20-16-01-WP-Task 20-2025 UWMP
1-3 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

This Joint 2025 UWMP is organized into the following chapters:
• Chapter 1: Introduction
• Chapter 2: Plan Preparation
• Chapter 3: Service Area Description
• Chapter 4: Water Use Characterization
• Chapter 5: SB X7-7 Baselines, 2020 Targets, and 2025 Reporting • Chapter 6: Normal-Year Water Supply Characterization
• Chapter 7: Water Service Reliability and Drought Risk Assessment • Chapter 8: Water Shortage Contingency Plan
• Chapter 9: Demand Management Measures
• Chapter 10: Plan Adoption, Submittal and Implementation This Joint 2025 UWMP also contains the following appendices of supplemental information and data related to the plan:
• Appendix A: Urban Water Management Planning Act Legislative Requirements • Appendix B: DWR 2025 Urban Water Management Plan Tables • Appendix C: DWR 2025 Urban Water Management Plan Checklist • Appendix D: Agency and Public Notices
• Appendix E: Water Sales Agreement
• Appendix F: Distribution System Water Loss Audits
• Appendix G: City of Turlock Water Shortage Contingency Plan • Appendix H: SRWA Water Shortage Contingency Plan
• Appendix I: UWMP and WSCP Adoption Resolutions
Furthermore, this Joint 2025 UWMP contains all the tables recommended in the DWR Guidebook, both embedded into the UWMP chapters where appropriate and included in Appendix B.

DWR’s UWMP Checklist, as provided in the DWR Guidebook, has been completed by West Yost to demonstrate the plan’s compliance with applicable requirements. A copy of the completed checklist is included in Appendix C.

N-C-693-20-16-01-WP-Task 20-2025 UWMP
2-1 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

CHAPTER 2
Plan Preparation
This chapter describes the preparation of SRWA and Turlock’s Joint 2025 UWMP and each agency’s WSCP, including the basis for the preparation of the plan, individual or regional planning, fiscal or calendar year reporting, units of measure, and plan coordination and outreach.

2.1 BASIS FOR PREPARING A PLAN
The Act requires every “urban water supplier” to prepare and adopt a UWMP, to periodically review its UWMP at least once every five years and make any amendments or changes which are indicated by the review. The Act also requires every “urban water supplier” to prepare and periodically update its WSCP.

While the WSCP is part of the UWMP, it may be adopted and amended separately from the UWMP. An “urban water supplier” is defined as a supplier, either publicly or privately owned, providing water for municipal purposes either directly or indirectly to more than 3,000 customers or supplying more than 3,000 acre-feet of water annually (AFY).

SRWA delivers treated water to its wholesale customers, the California Cities of Turlock and Ceres. Turlock and Ceres have approximately 19,769 and 11, 881 active water service connections , respectively.

Therefore, SRWA and the Cities of Turlock and Ceres are required to prepare an UWMP and periodically update its WSCPs. This Joint 2025 UWMP has been prepared by SRWA and the City of Turlock. While the City of Ceres 2025 UWMP has been prepared separately, this Joint 2025 UWMP has been coordinated with the City of Ceres to ensure consistency and accuracy between the two plans.

SRWA’s last UWMP, the 2020 UWMP, was adopted by the SRWA Board in October 2024. SRWA’s WSCP was adopted concurrently with the 2020 UWMP in October 2024 by separate resolution. Turlock’s last UWMP and WSCP, the 2020 UWMP and WSCP, was prepared separately from SRWA and adopted by the Turlock City Council May 25, 2021.

As shown in Table 2-1 (DWR Table 2-1 Retail), the Cities of Turlock and Ceres provided water to a total of approximately 31,650 active customer connections and supplied a total volume of 8,338 million gallons (MG) of potable water in 2025.

Table 2-1. Public Water Systems (DWR Table 2-1 Retail)

CA5010019 City of Turlock 19,769 6,146
CA5010028 City of Ceres 11,881 2,192
31,650 8,338Total
Public Water System
Number
Public Water System
Name
Number of Municipal
Connections 2025
NOTES: Number of municipal connections includes active connections only. Volume of water supplied includes both retail water and wholesale water purchases.

Volume of Water
Supplied 2025 (MG)
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

Chapter 2
Plan Preparation

N-C-693-20-16-01-WP-Task 20-2025 UWMP
2-2 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

2.2 REGIONAL PLANNING
As described in Section 2.3, SRWA and Turlock have prepared this Joint 2025 UWMP on an individual reporting basis, not part of a regional planning process. However, SRWA and Turlock coordinate routinely with each other , and with the City of Ceres and neighboring water agencies, to ensure that a safe and reliable water supply is delivered to existing customers and that plans for serving future customers are implemented as efficiently as possible.

2.3 INDIVIDUAL OR REGIONAL PLANNING AND COMPLIANCE
This Joint 2025 UWMP has been prepared on an individual reporting basis covering only SRWA and Turlock’s service area, as shown in Table 2-2 (DWR Table 2-2). SRWA and Turlock did not participate in a regional alliance for the preparation of this Joint 2025 UWMP and, therefore has not prepared a Regional Urban Water Management Plan (RUWMP). As described in Section 2.5, SRWA and Turlock have notified and coordinated planning and compliance with appropriate regional agencies and constituents.

Table 2-2. Plan Identification (DWR Table 2-2)

2.4 FISCAL OR CALENDAR YEAR AND UNITS OF MEASURE
SRWA is a water wholesaler that sells water to other agencies who then sell it to individual water users (e.g., residents and businesses). As described in detail in Chapter 3, SRWA is a recently formed Joint Powers Authority. SRWA’s customers consist of the Cities of Turlock and Ceres, jointly referred to as the Cities. SRWA commenced water deliveries to the Cities in November 2023. Turlock is a water retailer.

This Joint 2025 UWMP has been prepared on a calendar year basis , with the calendar year starting on January 1 and ending on December 31 of each year. Water use and planning data for the entire calendar year of 2025 has been included.

The water volumes in this Joint 2025 UWMP are reported in units of MG.

SRWA and Turlock’s reporting methods for this Joint 2025 UWMP are summarized in Table 2-3 (DWR Table 2-3).

Water Supplier is also a member of a
SB X7-7 Regional Alliance
Name of Regional Alliance or
RUWMP (Drop Down List)
Select
One or
Both
Type of Plan
Individual UWMP
Regional Urban Water Management Plan
(RUWMP)

Chapter 2
Plan Preparation

N-C-693-20-16-01-WP-Task 20-2025 UWMP
2-3 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 2-3. Supplier Identification (DWR Table 2-3)

2.5 COORDINATION AND OUTREACH
This section includes a discussion of SRWA and Turlock’s inter-agency coordination and coordination with the general public. The UWMP Act requires SRWA and Turlock to coordinate the preparation of the Joint 2025 UWMP and each of their WSCPs with other appropriate agencies and all departments within Turlock, including other water suppliers that share a common source, water management agencies, and relevant public agencies. These agencies, as well as the public, participated in the coordination and preparation of this Joint 2025 UWMP and are summarized in the sections that follow.

2.5.1 Wholesale and Retail Coordination
SRWA is a water wholesaler that delivers treated water to its two retail customers, the Cities of Turlock and Ceres. Turlock is a water retailer and receives wholesale water from SRWA. In accordance with CWC § 10631, Turlock informed SRWA of its projected water use for that wholesale source in five -year increments through 2050, as shown in Table 2-4 (DWR Table 2 -4 Retail). As shown in Table 2 -5 (DWR Table 2-4 Wholesale), SRWA provided information to the Cities of Turlock and Ceres , identifying and quantifying wholesale water supplies available for the same period, under normal water year, single dry year, and five dry years hydrological conditions.

Table 2-4. Retail: Water Supplier Information Exchange (DWR Table 2-4 Retail)

Supplier is a wholesale supplier
Supplier is a retail supplier
UWMP Tables are in calendar years
UWMP Tables are in fiscal years
Unit MG
Type of Supplier (select one or both)
Fiscal or Calendar Year (select one)
Units of measure used in UWMP
(Select from the drop down list).

DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent
throughout the UWMP as reported in Submittal Table 2-3.

The retail Supplier has informed the following wholesale supplier(s) of projected water use in accordance with Water Code Section 10631 (h).

Wholesale Water Supplier Name
Stanislaus Regional Water Authority (SRWA)

Chapter 2
Plan Preparation

N-C-693-20-16-01-WP-Task 20-2025 UWMP
2-4 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 2-5. Wholesale: Water Supplier Information Exchange (DWR Table 2-4 Wholesale)

2.5.2 Coordination with Other Agencies and the Community SRWA and Turlock actively encourage community participation in water management activities and specific water-related projects. SRWA and Turlock’s public participation program s use both active and passive means of obtaining input from the community, including mailings, public meetings, and web-based communication. T urlock’s website provides information on on-going projects and posts announcements about planned rate increases to fund these projects.

As part of the Joint 2025 UWMP, SRWA and Turlock facilitated a public review period. Public notic es, pursuant to Section 6066 of the Government Code, were issued to nearby water agencies and the community prior to commencement of this public comment period. Public hearing notices are included in Appendix D of this plan. During the public comment period, the Draft Joint 2025 UWMP was made available on SRWA and Turlock’s websites. During this same period, Turlock’s updated WSCP was made available on Turlock’s website.

SRWA and Turlock also coordinated the preparation of the Joint 2025 UWMP and Turlock’s updated WSCP with several agencies, including relevant public agencies that utilize the same water supplies. These agencies included the following:
• City of Ceres,
• City of Hughson (Hughson),
• City of Modesto (Modesto),
• Stanislaus County,
• Merced County,
• Denair Community Services District,
• Hilmar County Water District,
• Del Puerto Water District,
• Eastside Water District,
Supplier has informed more than 10 other water suppliers of water supplies available in accordance with Water Code Section 10631(h).

Completion of the table below is optional. If not completed, include a list of the water suppliers that were informed.

Provide page number for location of the list.

Supplier has informed 10 or fewer other water suppliers of water supplies available in accordance with Water Code Section 10631(h).

Complete the table below.

Water Supplier Name
City of Turlock
City of Ceres

Chapter 2
Plan Preparation

N-C-693-20-16-01-WP-Task 20-2025 UWMP
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Joint 2025 Urban Water Management Plan
May 2026

• Keyes Community Services District,
• Turlock Irrigation District,
• Merced Irrigation District,
• Modesto Irrigation District,
• California State University, Stanislaus,
• East Stanislaus Integrated Regional Water Management, • East Turlock Subbasin GSA,
• West Turlock Subbasin GSA, and
• North Valley Regional Recycled Water Program.

The public hearing provided an opportunity for all water users and the general public to become familiar with the Joint 2025 UWMP, ask questions about SRWA and Turlock’s water supply, and learn about on- going plans to ensure a reliable, safe, high-quality water supply.

2.5.3 Notice to Cities and Counties
CWC § 10621 (b) requires agencies to notify the cities and counties to which they serve water at leas t 60 days in advance of the public hearing that the plan is being updated and reviewed. In December 2025, a notice of preparation was sent to the cities and counties and other stakeholders, to inform them of the UWMP update process and schedule , and to solicit input for the Joint 2025 UWMP and Turlock’s WSCP Update. A copy of this notice of preparation is included in Appendix D. The notifications to cities a nd counties, the public hearing notifications, and the public hearing and adoption are discussed in Chapter 10 of this report.

N-C-693-20-16-01-WP-Task 20-2025 UWMP
3-1 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

CHAPTER 3
Service Area Description
This chapter provides a description of SRWA and the City of Turlock’s water service area and water system, including the water system facilities, climate, population, and demographics within the water service area.

3.1 GENERAL DESCRIPTION
In 2011, the Cities of Ceres and Turlock established the SRWA, a Joint Powers Authority, to implement and oversee the Regional Surface Water Supply Project (RSWSP). The RSWSP is a collaborative effort to provide treated drinking water from the Tuolumne River to supplement the Cities’ existing groundwater supplies and promote recharge to the local groundwater basin. SRWA was formed with the goal of providing an improved and more reliable water supply to meet the potable water demands for the Cities as well as meeting current and future anticipated drinking water standards. The need to supplement and diversify the Cities’ existing water supply was the driver for the creation of SRWA.

In 2015, SRWA and Turlock Irrigation District (TID) entered into a 50 -year agreement, which provides SRWA the contractual right to purchase up to 30,000 acre -ft per year of Tuolumne River surface water from TID (see Appendix E). Construction of the RSWSP treatment and delivery facilities began in July 2020, and SRWA began delivering treated surface water to its customers, the Cities, in November 2023.

SRWA and Turlock ’s service area is located within Stanislaus County in the San Joaquin Valley, approximately 85 miles southeast of the City of Sacramento. The San Joaquin Valley is bounded by the Sacramento-San Joaquin River Delta to the north, the Tehachapi Mountains to the south, the Sierra Nevada to the east, the Coast Ranges to the west.

3.2 SERVICE AREA BOUNDARY
As SRWA serves the Cities of Turlock and Ceres (Cities), its service area is contiguous with the water service areas of both Cities. The following section describes the geographical service area boundaries for the Cities.

Figure 3-1 shows the Cities’ water service area s, city limits, and sphere s of influence (SOI). Figure 3-2 is provided to show additional detail on Turlock’s service area, city limits, SOI , and Urban Development Boundary (UDB) . The SOI is a boundary that encompasses lands that are expected to ultimately be annexed by the city for urban development based on the Cities’ respective General Plans (GPs). The Cities’ SOI boundary is determined by the Stanislaus County Local Agency Formation Commission. The UDB, also known as the Study Area in Turlock's GP, represents the greatest extent to which urban development may take place within the 2012 GP planning horizon.

3.2.1 City of Turlock
Turlock’s city limits encompass approximately 14 square miles (8,730 acres). Except for three small residential areas served with groundwater from Modesto, Turlock serves the entire area encompassed by its city limits, including residential, commercial, industrial, and institutional uses, as shown on Figure 3-1.

Turlock’s SOI extends farther south-east and encompasses approximately 20 square miles (12,910 acres).

Turlock’s UDB extends farther west of Highway 99 than the SOI and encompasses a total of 27 square miles (17,460 acres).

Additional information on the City’s service area characteristics can be found in the Turlock GP, adopted in September 2012.

Chapter 3
Service Area Description

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Joint 2025 Urban Water Management Plan
May 2026

3.2.2 City of Ceres
Ceres’ city limits and existing water service area encompass an area of approximately 9.4 square miles (6,000 acres). Ceres’ water service area is generally contiguous with its city limits, as shown on Figure 31.

However, there are some small pockets located in the northwest portion of Ceres (North Ceres) and the southwest portion of Ceres (Crows Landing/East Whitmore Area) that are currently served by the City of Modesto. The City of Ceres also provides water service to a small number of customers that are located outside of its city limits. Ceres’ SOI extends from the city limits into North Ceres, as well as farther south- east and south-west, and encompasses a total area of approximately 13 square miles (8,440 acres).

Additional information on the City of Ceres’ service area characteristics can be found in the Ceres 2035 GP, adopted in May 2018.

3Q
UT
UT
D
R
Y
C
R
E
E
K
S
A
N
J
O
A
Q
U
I
N
R
I
V
E
R

T U O L U M N E R
I V
E
R
ÄÆ
99 E WHITMORE AVE

E KEYES RD

CROWS LANDING RD

GEER RD

CENTRAL AVE

TULLY RD

MITCHELL RD

N GOLDEN STATE BLV

MORGAN RD

E MONTE VISTA AVE

EAST AVE

YOSEMITE BLV

S CARPENTER RD

FULKERTH RD

E HATCH RD

E SERVICE RD

VIVIAN RD

ROEDING RD

BERKELEY AVE

WEST MAIN ST

S SANTA FE AVE

N SANTA FE AVE
CERES

TURLOCK

HUGHSON

MODESTO
Ceres
Terminal
Tank
Turlock
Terminal
Tank
Notes:

1. The Sphere of Influence (SOI) is a
boundary that encompasses lands
that are expected to be ultimately
annexed by the City per the City's
most recent General Plan.

2. Turlock's indicated existing water
service area includes three small areas
that are served by the City of Modesto.

3. RSWSP: Regional Surface Water Supply
Project.
3Q RSWSP Water Treatment Plant
UT Terminal Storage Tank
Existing Water Service Area
City Limits
Sphere of Influence
Pipelines
Finished Water Transmission Main
Raw Water Transmission Main
Figure 3-1
SRWA Water
Service Area
0 21
Miles
N
Stanislaus Regional Water Authority
City of Turlock
Joint 2025 Urban Water
Management Plan
Prepared for:

Prepared by:

SRWA 2025 UWMP Service Area: N:\Clients\341 City of Ceres\60-23-18 WMP Update\GIS\Ceres WMP Update.aprx - nthompson - 12/31/2025

ÄÆ
99 W LINWOOD AVE

S WALNUT RD

E MONTE VISTA AVE

COLORADO AVE

LESTER RD

E HAWKEYE AVE

COUNTRYSIDE DR

N WALNUT RD

W CANAL DR

W MONTE VISTA AVE

N GRATTON RD

N TULLY RD

N JOHNSON RD

E ZEERING RD

LANDER AVE

N GOLDEN STATE BLV

W TAYLOR RD

CLAYTON RD

WEST MAIN ST

N DAUBENBERGER RD

N OLIVE AVE E TUOLUMNE RD

N BERKELEY AVE

S PRAIRIE FLOWER RD

GEER RD

N SANTA FE AVE

W TUOLUMNE RD

EAST AVE

FULKERTH RD

PAULSON RD

E CANAL DR

E LINWOOD AVE

S COMMONS RD

S WASHINGTON RD

W CHRISTOFFERSEN PKWY

E TAYLOR RD

S TEGNER RD

S GOLDEN STATE BLV

N WARING RDN WASHINGTON RD

W HARDING RD

W BARNHART RD

E BARNHART RD

N QUINCY RD

S FAITH HOME RD

TURLOCK
Notes:

1. The Sphere of Influence (SOI) is a
boundary that encompasses lands
that are expected to be ultimately
annexed by the City per Turlock's
General Plan, adopted in 2012.

2. The Urban Development Boundary (UDB),
also known as the Study Area in Turlock's
General Plan, represents the greatest
extent to which urban development may
take place within the 2012 General Plan's
planning horizon.

3. Turlock's indicated existing water
service area includes three small areas
that are served by the City of Modesto,
which are displayed in orange.

Turlock Water Service Area
City Limits
Sphere of Influence
Urban Development Boundary
Area Served by City of Modesto
Figure 3-2
City of Turlock
Water Service Area
0 10.5
Miles
N
Stanislaus Regional Water Authority
City of Turlock
Joint 2025 Urban Water
Management Plan
Prepared for:

Prepared by:

SRWA 2025 UWMP Turlock Service Area: N:\Clients\341 City of Ceres\60-23-18 WMP Update\GIS\Ceres WMP Update.aprx - nthompson - 1/9/2026

Chapter 3
Service Area Description

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Joint 2025 Urban Water Management Plan
May 2026

3.3 SERVICE AREA CLIMATE
SRWA and Turlock’s service area climate is considered an inland Mediterranean climate, with warm to hot and dry summers, and cool and rainy winters. The climate ranges from summer temperatures occasionally exceeding 90 degrees Fahrenheit (°F), and winter temperatures dropping into the mid -30°F range.

Precipitation in the area averages about 12.2 inches per year.

Water use within the service area is dependent on various climate factors such as temperature, precipitation, and evapotranspiration (ET). Climate data, including temperature and precipitation estimates, were obtained for the service area from the Western Regional Climate Center and the California Irrigation Management Information System (CIMIS).

ET describes the combined water lost through evaporation from the soil and surface water bodies and plant transpiration. In general, the ET is given for turf grass and then corrected for a specific crop type.

Local ET data was obtained from the CIMIS monitoring station in West Modesto (Station #71). The historical climate characteristics affecting water management in the service area are shown in Table 3-1.

Table 3-1. Monthly Average Climate Data Summary(a)
Month
Standard Monthly
Average ET, inches(a)
Average Total
Rainfall, inches(b)
Average Temperature, degrees Fahrenheit(a)
Minimum Maximum
January 1.17 2.44 36.4 55.8
February 1.98 2.07 37.9 61.3
March 3.61 1.93 40.2 66.4
April 5.26 1.03 43.3 71.7
May 6.98 0.46 47.9 78.9
June 7.96 0.13 52.3 85.8
July 8.03 0.02 55.9 90.7
August 6.96 0.04 55.2 89.2
September 5.20 0.17 52.3 85.7
October 3.54 0.63 46.1 76.9
November 1.79 1.24 38.9 64.7
December 1.09 2.05 35.4 55.5
Total 53.6 12.2 - -
(a) California Irrigation Management Information System (https://cimis.water.ca.gov/) for Station #71. Period of record is years 1990 through 2025. Data accessed 12/31/2025.
(b) Western Regional Climate Center (https://wrcc.dri.edu/) data for Modesto City Station (045738). Period of record is years 1906 through 2016. Data accessed 12/31/2025.

The region is subject to wide variations in annual precipitation. The 2020 rainfall season (defined as the period from July 1, 2019 through June 30, 2020) was relatively dry, with a total rainfall of 6.5 inches. The 2021 and 2022 seasons were similarly dry, with total rainfall of 9.4 inches and 10.0 inches, respectively.

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In contrast, the 2023 and 2024 seasons were relatively wet with 18.9 and 15.3 inches of rain respectively.

The 2025 season returned to dry conditions, with only 7.7 inches of total rainfall.1 As described in Chapter 4, the Cities’ retail water use in the summer months is significantly higher than that in the winter, reflecting increased water use for irrigation purposes during the hot, dry summers.

3.4 SERVICE AREA POPULATION AND DEMOGRAPHICS

3.4.1 Service Area Population
SRWA provides water to the Cities. Both cities are projected to experience significant population growth by 2050, which is expected to lead to increased water demand within the service areas.

As both Cities’ water service areas generally align with their respective City limits, current (2025) service area population was estimated for both Cities based on data published by the US Census Bureau and/or California Department of Finance (DOF).

Table 3-2 (DWR Table 3 -1 Retail) shows the City of Turlock’s current and projected water service area population. The City of Turlock’s current service area population is estimated to be 72, 682, consistent with the City’s population estimate in its 2024 Electronic Annual Report (eAR) submission to the State Water Resources Control Board. This population estimate was based on the City of Turlock’s most recent (2020) US Census Bureau estimate. Future population in Turlock is estimated to increase from its current population at an annual growth rate of 1.9 percent, consistent with the annual growth rate projected in the City’s 2012 GP . This growth rate yields a population of 11 6,354 persons by 2050. Growth and development within Turlock’s service area are subject to City and County growth management policies.

Table 3-2. City of Turlock Population – Current and Projected (DWR Table 3-1 Retail)

Table 3-3 shows the current and projected population for both the Cities of Turlock and Ceres. Turlock’s population estimates are consistent with Table 3 -2 (DWR Table 3 -1 Retail). The City of Ceres’ current service area population is estimated to be 54,513 based on Ceres’ Domestic Water Supply Permit Amendment updated in November 2025. Consistent with the Ceres 2025 UWMP, the City of Ceres’ future population growth was extrapolated from the 2025 actual population estimate, assuming Ceres will reach its buildout population of 79,000 persons as defined in the Ceres 2035 GP. Based on discussions with the City of Ceres staff, GP buildout is assumed to occur by 2045, which is later than the GP’s original estimate of 2035. This calculated growth rate for Ceres is equivalent to a 1.87 percent annual growth rate, which is similar to the City of Turlock’s projected growth rate of 1.9 percent.

1 Modesto Irrigation District. Historical Rainfall. Accessed at https://www.mid.org/weather/historical-rainfall/ on December 31, 2025.
2025 2030 2035 2040 2045 2050(opt)
72,682 79,854 87,734 96,392 105,904 116,354
Population
Served

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Table 3-3. Cities of Turlock and Ceres – Current and Projected Population 2025 2030 2035 2040 2045 2050
Turlock(a,b) 72,682 79,854 87,734 96,392 105,904 116,354 Ceres(c,d) 54,513 59,811 65,624 72,002 79,000 79,000
(a) Turlock’s 2025 service area population estimate aligns with its 2024 Electronic Annual Report submission to the State Water Resources Control Board and is based on the City of Turlock’s 2020 US Census Bureau data. (b) Turlock’s future population growth was extrapolated from the 2025 actual population using a 1.9 percent annual growth rate, consistent with the annual growth rate projected in Turlock’s 2012 General Plan. (c) Ceres’ 2025 service area population estimate is based on the City of Ceres’ Domestic Water Supply Permit Amendment updated in November 2025.
(d) Ceres’ future population growth was interpolated from the 2025 actual population, assuming Ceres will reach its buildout population of 79,000 residents as defined in the Ceres 2035 General Plan. Buildout is assumed to occur by 2045, which is later than the General Plan’s original estimate of 2035.

SRWA itself does not directly serve any urban water customers and , therefore, does not have population of its own. The combined populations of SRWA’s retail water suppliers are shown in Table 3-4 (DWR Table 3-1 Wholesale), consistent with Table 3 -3 above.

Table 3-4. Total Wholesale Population of Cities of Turlock and Ceres – Current and Projected (DWR Table 3-1 Wholesale)

3.4.2 Other Social, Economic, and Demographic Factors
The State requires the inclusion of service area socioeconomic information as part of the service area description in UWMPs. However, differences in household water use across sociodemographic groups in the Cities of Turlock and Ceres have not been studied. Therefore, the following social, economic, and demographic information is being provided to comply wi th the CWC but does not include conclusions about socioeconomic factor effects, or potential effects, on water use . The information was derived from the US Census Bureau’s most recent 5-Year profile of the Cities of Turlock and Ceres for 20 19 through 2023.2
All of the Cities’ water utility customers are metered.

2 United States Census Bureau. American Community Survey, 2023: ACS 5-Year Estimates Data Profiles for Turlock City, California and Ceres City, California. Accessed at https://data.census.gov/table/ACSDP5Y2023.DP03?g=160XX00US0680812&d=ACS+5-Year+Estimates+Data+Profiles on January 6, 2026.
2025 2030 2035 2040 2045 2050(opt)
127,195 139,665 153,358 168,394 184,904 195,354
Population
Served
NOTES: Population estimates include both Cities of Turlock and Ceres, consistent with Table 3-3.

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3.4.2.1 City of Turlock
The 2023 American Community Survey ( ACS) 5-Year Estimates specify the following regarding Turlock’s social, economic, and demographic factors for the Years 2019 to 2023:
• The average number of people per household was 2.82.
• The median household income in 2023 was $79,807, while 10.8 percent of all individuals and 11.7 percent of youth under the age of 18 lived in poverty. • The average unemployment rate was 7.8 percent.
• The owner-occupied housing unit rate was 56.8 percent. • The median gross rent was $1,498 per month.
• The median age was 34.6 years.
• Of persons 25 years or older, 81.7 percent had earned at least a high school diploma or equivalent and 26.6 percent had earned a bachelor’s degree or higher. • Of persons between 18 and 64 years of age, 10.3 percent had a disability and 5.1 percent did not have health insurance.
• 94.9 percent of households had one or more type of computer, and 91.1 percent had a broadband internet subscription.
• By race/ethnicity, 54.5 percent of people were White, 2.1 percent were Black, 0.4 percent were American Indian or Alaska Native, 5.9 percent were Asian, 0.1 percent were Hawaiian Native or Pacific Islander, 14.9 percent were two or more races, and 22.1 percent were some other race(s).
• Of the total City population, 43.6 percent were Hispanic or Latino and 56.4 were not Hispanic or Latino.
• Approximately 21.4 percent of residents were foreign born, and 42.8 percent of people ages five years and older spoke a language other than English at home.

3.4.2.2 City of Ceres
The 2023 ACS 5 -year Estimates specif y the following regarding the City of Ceres’ social, economic, and demographic factors for the Years 2019 to 2023:
• The average number of people per household was 3.51.
• The median household income in 2023 was $76,862, while 14.4 percent of all individuals and 21.7 percent of youth under the age of 18 lived in poverty. • The average unemployment rate was 10.4 percent.
• The owner-occupied housing unit rate was 63.7 percent. • The median gross rent was $1,584 per month.
• The median age was 32.7 years.
• Of persons 25 years or older, 74.3 percent had earned at least a high school diploma or equivalent and 13.0 percent had earned a bachelor’s degree or higher. • Of persons between 18 and 64 years of age, 10.3 percent had a disability and 7.6 percent did not have health insurance.

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• 94.1 percent of households had one or more type of computer, and 91.4 percent had a broadband internet subscription.
• By race/ethnicity, 36.9 percent of people were White, 1.1 percent were Black, 1.0 percent were American Indian or Alaska Native, 9.7 percent were Asian, 0.2 percent were Hawaiian Native or Pacific Islander, 34.0 percent were two or more races, and 17.1 percent were some other race(s).
• Of the total City population, 65.6 percent were Hispanic or Latino and 34.4 were not Hispanic or Latino.
• Approximately 27.7 percent of residents were foreign born, and 60.0 percent of people ages five years and older spoke a language other than English at home.

3.5 LAND USES WITHIN SERVICE AREA
This section describes the current and projected land uses for the Cities. Information for this section is based on the Turlock GP, adopted in September 2012, and the Ceres General Plan 2035, adopted in May 2018.

3.5.1 City of Turlock
The Turlock GP describes land use updates for the entirety of its city limits, areas within the City’s SOI, and areas outside of city limits and the SOI, defined as the “Planning Area.” The City will expand water service within the City’s SOI and within the Planning Area as land is annexed into the City.

Per the Turlock GP, the City’s current land use within city limits is primarily residential neighborhoods at 41 percent of total area. The majority of Turlock’s residential development is low -density single-family homes, ranging from three to seven dwelling units per acre. Approximately 16 percent of city limits is agriculture, 11 percent industrial, 9 percent commercial, 8 percent public facilities, 2 percent parks, and 1 percent office. The remaining 12 percent is vacant land, which offer development opportunities.

According to the Turlock GP, there are four Master Plan Areas: Southeast 1 (SE1), Southeast 2 (SE2), Southeast 3 (SE3), and Montana-West. These Master Plan Areas represent development areas that shall be planned, pre -zoned, and annexed into the City. These four Master Plan Areas are briefly described below:
• SE1 is 170 acres and will be developed as a primarily residential neighborhood with small office and commercial areas.
• SE2, with 320 acres, will also be a majority residential neighborhood with a small office center. • SE3 is the largest Master Plan Area at 700 acres, which will have a mix of land uses. SE3 includes land for residential neighborhoods, industrial area, public use, park, and a neighborhood center.
• Montana-West is 50 acres and includes seven unincorporated County Islands; this area will be majority low-density residential and vacant lots.

3.5.2 City of Ceres
The Ceres GP 2035 describes land use updates for the entirety of its city limits, areas within the City of Ceres’ SOI, and areas outside of city limits and the SOI, defined as the “General Plan Planning Area .” The

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City of Ceres will expand water service within the City’s SOI and within the GP Planning Area as land is annexed into Ceres.

The City of Ceres’ current land use within city limits is primarily single family residential at 39 percent of total area. Approximately 9 percent of the land within the city limits is industrial, 8 percent public and community facilities, 6 percent agriculture, 5 percent commercial, 4 percent parks and open space, and 7 percent vacant. The remaining area includes other land uses such as public streets and transportation rights-of-way.

The Ceres GP 2035 specifies the following regarding projected future land uses:
• A guiding principle for future development is to encourage infill development and investment within existing neighborhoods and commercial corridors to revitalize areas within the City limits.
• The City anticipates development in four Specific Plan (SP) areas including the West Landing SP, Downtown SP, Mitchell Road Corridor SP, and Whitmore Ranch SP. — Much of the growth is planned to be residential development. — Some growth may occur outside of City limits and into the greater SOI, such as the Whitmore Ranch SP, which would expand the City’s water service area boundary. • Additional sites with potential for development include vacant/underutilized properties and rural or agricultural plots within the City limits and the SOI. — The GP identifies 541 acres of vacant land, 121 acres of underutilized land, 1,076 acres of rural land, and 187 acres of additional sites identified in the Housing Element within the Ceres SOI.

The Ceres GP 2035 also include s future land use designations from the Copper Trails Specific Plan, although the Specific Plan was not finalized and adopted by Ceres at the time of GP adoption.

3.6 WATER SYSTEM FACILITIES
This section summarizes SRWA and the City’s water system facilities. SRWA’s facilities include the RSWSP raw water facilities and the Water Treatment Plant (WTP). The RSWSP pumps surface water from the Tuolumne River, treats the water at a WTP, and distributes treated water to Ceres and Turlock.

3.6.1 SRWA Raw Water Facilities
The RSWSP’s raw water facilities include the infiltration gallery, raw water pump station, and raw water transmission main. The infiltration gallery and raw water pump station are located on the Tuolumne River, just west of Geer Road and less than 0.5 mile west of the WTP. Surface water from the Tuolumne River is drawn through the infiltration gallery, which is comprised of a set of perforated pipelines installed in gravel about 8 feet below the bottom of the riverbed, into the wet well of the raw water pump station.

The raw water pump station then conveys water to the flow split structure; at the flow split structure, the raw water is directed to the WTP for treatment, or to the Ceres Main Canal outfall structure for use as irrigation water by TID. The raw water facilities are owned by TID and leased to SRWA.

The raw water pump station’s current capacity is 15 million gallons per day (MGD) provided by one pump and one additional standby pump. Full buildout will include five pumps and one additional standby pump

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for a total capacity of 65 MGD. The flow can be split between the WTP and the Ceres Main Canal as required. The WTP is intended to treat up to 45 MGD of raw water at buildout.

3.6.2 SRWA Water Treatment Plant
SRWA’s WTP currently has a capacity of 15 MGD and meets disinfection requirements through a combination of conventional treatment, ozone disinfection, and chlorine disinfection when necessary.

Raw water from the raw water pipeline enters the WTP at the rapid mixing facility. After coagulants and other chemicals are added during rapid mixing, water flows into the flocculation and sedimentation basins for removal of suspended solids. The flow then enters the ozone facility for ozone disinfection. Following disinfection, water is filtered via gravity through granular media filters and enters the WTP clearwell. From the clearwell, treated water is pumped via the finished water pump station into the C eres or Turlock finished water transmission mains.

The WTP has an existing capacity of 15 MGD at a maximum filtration rate of 6 gallons per minute per square foot (GPM/SF) from four rapid sand filters with granular activated carbon and sand dual media.

Higher filter loading rates may be feasible, and a filter re-rating study to increase the filter loading rate to 8 GPM/SF is planned. If the filters can be re -rated to 8 GPM/SF, the WTP capacity will increase to

19.9 MGD. The filter re -rating testing is planned to be completed in 2027; the added WTP capacity is expected to be available beginning in 2028.

SRWA’s WTP was designed to allow for future expansion of treatment capacity by adding additional parallel treatment trains within the existing site. Information on planned future expansions to meet projected water demands is provided in Chapter 6 and Chapter 7.

3.6.3 SRWA Finished Water Transmission Pipelines
Potable water is pumped to SRWA’s wholesale customers via the Ceres and Turlock finished water transmission mains. Each transmission main terminates at the Cities’ respective terminal storage tank for distribution to the Cities’ water systems.

3.6.4 City of Turlock Water System Facilities
The City of Turlock’s major water system facilities include:
• 15 active groundwater wells with a total capacity of approximately 31.9 MGD, • 3 at-grade storage tanks and 1 terminal storage tank with a total storage capacity of 5.3 MG, • 4 pump stations (one at each storage tank) with a total firm pumping capacity of

35.4 MGD, and
• approximately 286 miles of water main, ranging in size from 1-inch to 42-inches in diameter.3 Turlock’s water system consists of one main pressure zone. Additional information on the City of Turlock’s water system facilities can be found in Turlock’s Water Master Plan, updated in March 2025.

3 City of Turlock, Carollo. March 2025. City of Turlock Water Master Plan.

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CHAPTER 4
Water Use Characterization
This chapter describes and quantifies the historical, current, and projected water uses for Turlock and SRWA. It discusses both Turlock’s retail water demands and SRWA’s wholesale water demands. As SRWA supplies treated surface water to the Cities, SRWA’s demand projections are based on the projected growth within each city’s water service area and the projected allocation between surface water and local groundwater use. Accurately tracking and reporting water demands allows Turlock and SRWA to properly analyze the use of their resources and conduct good water resource planning.

Additional information on the City of Ceres’ historical, current, and projected retail water use is provided separately in the Ceres 2025 UWMP.

4.1 NON-POTABLE VERSUS POTABLE WATER USE
Potable water is water that is safe to drink and has had various levels of treatment and/or disinfection.

Non-potable water is not safe to drink and includes both raw water and recycled water.

Turlock supplies treated groundwater to customers within its service area from city-owned and operated wells, as well as treated surface water purchased from SRWA. SRWA provides wholesale potable water to the Cities by treating surface water diverted from the Tuolumne River.

Raw water is untreated, non -potable water that is used in its natural state or with minimal treatment.

Turlock uses raw water from shallow, on -site wells at several local parks for landscape irrigation. These wells are not part of Turlock’s potable water system. SRWA does not currently deliver raw water to its wholesale customers, nor does it have plans to do so.

Recycled water is municipal wastewater that has been treated to a specified quality to enable it to be used for beneficial purposes. Turlock treats its wastewater to Title 22 disinfected tertiary recycled water standards, suitable for unrestricted non-potable use. Within its service area, Turlock provides recycled water to TID’s Walnut Energy Center Co-Generation Facility for cooling, to the Pedretti Sports Field for landscape irrigation, and to a recycled water fill station for local non-potable uses. However, most of Turlock’s recycled water is exported outside its service area for agricultural irrigation as part of the North Valley Regional Recycled Water Program, discussed further in Chapter 6. SRWA does not currently deliver recycled water to its wholesale customers, nor does it have plans to do so.

Maintaining multiple water sources allows Turlock to best meet its customers’ range of needs, as some industrial and irrigation uses do not require the same level of treatment as is required for drinking water.

Potable and non-potable water demands are discussed in the following sections.

4.2 WATER USE BY SECTOR
This section describes Turlock and SRWA’s past, current, and projected water use by water use sector, as listed in CWC §10631(d) and defined in the DWR Guidebook. These classifications were used to analyze current consumption patterns among the various types of Turlock’s water customers. Each of Turlock’s retail water use sectors are listed and defined below.
• Single Family Residential: A single-family dwelling unit. A lot with a free-standing building containing one dwelling unit that may include a detached secondary dwelling. • Multi-Family Residential: Multiple dwelling units contained within one building or several buildings within one complex.

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• Commercial: A water user that provides or distributes a product or service (CWC§10608.12(d)).
• Industrial: A water user that is primarily a manufacturer or processor of materials as defined by the North American Industry Classification System Code Sectors 31 to 33, inclusive, or an entity that is a water user primarily engaged in research and development (CWC §10608.12(h)).
• Institutional/Governmental: A water user dedicated to public service. This type of user includes, among other users, higher education institutions, schools, courts, churches, hospitals, government facilities, and nonprofit research institutions (CWC §10608.12(i)). • Landscape: Water connections supplying water solely for landscape irrigation. Such landscapes may be associated with multi-family, commercial, industrial, or institutional/governmental sites, but are considered a separate water use sector if the connection is solely for landscape irrigation.
• Sales to Other Agencies: Water delivered to another water agency. • Other: Any other water demand that is not adequately described by the water sectors defined above, including fire flows and construction water. System water losses are not to be reported in the “Other” category.

Because SRWA does not directly serve retail customers, the only DWR defined sector relevant to SRWA is “sales to other agencies”, which are water sales made to the Cities. Projected sales are based on projected water demand provided by the receiving agency. There is inherent uncertainty in future demand projections and, therefore, any projected sales reported in the UWMP are for planning purposes only and are not considered a commitment on the part of the wholesaler or retailer.

Turlock and SRWA do not have any current plans to use water for groundwater recharge, saline water intrusion barriers, agricultural irrigation, wetlands, or wildlife habitat.

4.2.1 Historical Water Use
Past water use in recent years for Turlock and SRWA are discussed in the following sections.

4.2.1.1 City of Turlock
Turlock’s potable water demand by water use sector from 2020 through 2024 is shown in Table 4-1. Water use in 2020 is based on values provided in Turlock’s 2020 UWMP, while 2021 through 2024 water use for each water use sector is from Turlock’s metered consumption data submitted to the State Water Board for annual water use reporting. Turlock completed its metering program in 2011, allowing the City to track actual water use by customer and sector. As shown in Table 4-1, single family residential customers and industrial customers have been the two largest water users over the past five years.

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Table 4-1. Historical Potable Water Demand by Water Use Sector (Retail), MG(a) Water Use Sector 2020 2021 2022 2023 2024
Single Family 2,964 2,859 2,590 2,293 2,420
Multi-Family 715 676 642 699 622
Commercial(b) 512 445 748 503 470
Industrial 1,504 1,452 1,400 1,279 1,386
Landscape 334 304 360 392 391
Other - City meters (non-billed) 216 229 161 99 110
Sales/Transfers/Exchanges -
Exported to City of Modesto 6 6 7 5 5
Distribution System Water Loss(c) 451 378 291 734 1,051 Other - Unmetered water(d) 42 106 0 9 55
Total(e) 6,743 6,456 6,199 6,012 6,510
(a) Annual demand by water use sector is from consumption data in Turlock's Electronic Annual Reports submitted to the State Water Board and from Turlock's Per-water-system data downloaded from the State Open Data Portal. (b) "Commercial" use includes institutional/governmental water use consistent with Turlock's annual water use reporting. (c) Losses are based on Turlock's annual AWWA Water Loss Audits. Losses in 2022 were re-calculated due to inconsistent authorized consumption values identified upon review of 2022 consumption data. (d) “Other – Unmetered water” was calculated based on the difference between total annual production (see footnote e), and total metered water consumption plus the water losses defined in Turlock’s AWWA Water Loss Audits. (e) Totals represent annual potable water production from groundwater and surface water sources and are based on Turlock's annual AWWA Water Loss Audits for all years but 2023. For 2023, the total production is based on data from the State Open Data Portal. The AWWA Water Loss Audit data for 2023 reported a lower total production (5,895 MG) compared to the State Open Data Portal (6,012 MG). Total billed metered consumption also appeared lower in the 2023 audit (5,041.5 MG) compared to the State Open Data Portal (5,165 MG).

Using the lower audit-based production would result in negative unmetered water values when combined with the higher consumption values from the State Open Data Portal, which is not physically plausible. Therefore, total production for 2023 is based on the State Open Data Portal and represents the sum of all listed use sectors, unmetered water, and distribution system water losses.

Totals shown are based on Turlock’s total annual water production (i.e., the sum of groundwater and surface water deliveries), per the City’s annual American Water Works Association (AWWA) Water Loss Audits. Distribution system water losses are also based on Turlock’s AWWA Water Loss Audits.

The volume exported to the City of Modesto shown in Table 4 -1 represents water sold to the City of Modesto’s Central Turlock water system. As described in Chapter 3, Turlock serves the entire area encompassed by its city limits except for three small residential water systems served by the City of Modesto. However, Turlock has been providing potable water to the Central Turlock water system via an interconnection , as the City of Modesto’s groundwater well previously supplying this system is no longer active.

Turlock has also historically used raw water and recycled water for non -potable uses within its service area. As shown in Turlock’s 2020 UWMP, Turlock used approximately 445 MG of raw water in 2020 to irrigate city parks using non-potable irrigation wells. Additionally, in 2020, Turlock supplied approximately 297 MG of disinfected tertiary recycled water to TID’s Walnut Energy Center Co-Generation Facility, and approximately 1 MG for landscape irrigation of Turlock’s Pedretti Sports Field. Turlock’s c urrent non-potable uses in 2025 are described in Section 4.2.2.1.

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4.2.1.2 SRWA
As previously discussed, SRWA commenced delivery of treated surface water to its wholesale customers in November 2023 . In 2023, SRWA delivered 33 MG of treated surface water to Turlock and 95 MG to Ceres, for a total volume of 128 MG.1 The total annual water supplied by SRWA to the Cities in 2024 was 2,274 MG and 1,431 MG, respectively, for a total volume of 3,705 MG.2 SRWA has not delivered potable, raw, or recycled water directly to urban retail customers in the past and does not plan to do so in the future.

4.2.2 Current Water Use
Current water use in 2025 for Turlock and SRWA is discussed in the following sections.

4.2.2.1 City of Turlock
Turlock’s water demand by sector in 2025 is reported in Table 4-2 (DWR Table 4-1 Retail). Turlock’s total potable water use in 2025 was 6,146 MG, including system losses. Turlock’s total non-potable water use in 2025 was 480 MG, which includes raw water for landscape irrigation at city parks and disinfected tertiary recycled water supplied to TID’s Walnut Energy Center and Turlock’s recycled water fill station.

1 Source: City of Turlock and City of Ceres 2023 AWWA Water Loss Audits. 2 Source: SRWA Annual Operations Report, June 2025.

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Table 4-2. Total Uses for Potable and Non-Potable Water – 2025 (DWR Table 4-1 Retail)

Distribution system water losses were estimated based on the difference in total potable water production (6,146 MG) and total metered potable water consumption.

4.2.2.2 SRWA
SRWA’s wholesale water demand in 2025 is reported in Table 4 -3 (DWR Table 4-1 Wholesale). The total treated surface water delivered to the Cities in 2025 was 3,517 MG. As shown, all water deliveries were treated to potable water standards.

Use Type
Drop down list
May select each use multiple times
These are the only use types that will be recognized by the WUEdata online submittal tool
Potable or Non-
Potable
(OPTIONAL)
Drop down list
Volume (MG)
Single Family Potable 2,338
Multi-Family Potable 557
Commercial Potable 453
Industrial Potable 1,254
Landscape Potable 265
Other (optional) City meters (non-billed) Potable 114
Sales/Transfers/Exchanges to other Suppliers Exported to City of Modesto Potable 5 Distribution System Water Loss Losses and unmetered water (e.g., Potable 1,160 Other (optional) Disinfected tertiary recycled water. See note (a). Non-Potable 376
Landscape Non-potable raw water irrigation wells at
City parks Non-Potable 104
6,146
480
6,625Total
NOTES: (a) Recycled water use shown includes only recycled water delivered within Turlock's service area. This volume includes recycled water delivered to TID's Walnut Energy Center for cooling, and a small amount of fill station use (<1 MG). Refer to Chapter 6 for additional detail on recycled water use.

DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

This table identifies the unit of measure selected in Submittal Table 2-3. 2025 Actual Water Use
Subtotal Potable
Subtotal Non-Potable
Additional Description
(as needed)

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Table 4-3. Total Uses for Potable and Non-Potable Water – 2025 (DWR Table 4-1 Wholesale)

4.2.3 Projected Water Use
Projected water use through 2050 for Turlock and SRWA are discussed in the following sections.

4.2.3.1 City of Turlock
Turlock’s projected potable and non -potable water demand s for 2030 through 2050 ( representing a 25-year planning horizon from 2025) are reported in Table 4-4 (DWR Table 4-2 Retail). Projected potable water demands are based on Turlock’s Water Master Plan (WMP), which was updated in March 2025.

The 2025 WMP projected potable water demands assuming buildout of both city limits and the broader Urban Development Boundary (UDB) by 2050. The WMP also assumed that the County enclaves (also referred to as “County islands ”) which are not currently served by the City will be annexed and incorporated into the Turlock water service area at some future point. To develop these projections, the 2025 WMP used the future land use designations defined in the Turlock GP, which was adopted in 2012.

Area-based water use factors were applied to these land use categories to estimate future water demands. In addition, the WMP incorporated water demand projections for several large, planned developments, using water use factors provided directly by developers.

Turlock’s total 2050 projected potable water demand is 9,892 MG, which represents an increase of 61 percent compared to its 2025 potable water demand (6,146 MG) . For the purposes of this UWMP, water demands for 2030 through 2050 were linearly interpolated using 2025 demands and the 2050 water demand projection.

To remain consistent with Turlock’s annual reporting to the State Water Board, public and institutional uses are included with commercial demand projections.

Projected recycled water and raw water demands within Turlock’s service area are expected to remain generally constant through 2050. Refer to Chapter 6 for further discussion of Turlock’s recycled water demands outside of its service area.

Use Type
Volume
(MG)
Sales to other agencies City of Turlock Potable 2,104
Sales to other agencies City of Ceres Potable 1,413
3,517
0 3,517
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

Total
2025 Actual Water Use
Subtotal Potable
Subtotal Non-Potable
Level of Treatment
When Delivered
(OPTIONAL)
Drop down list
Additional Description
(as needed)
Drop down list
May select each use multiple times
These are the only use types that will be
recognized by the WUEdata online
submittal tool

Chapter 4
Water Use Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
4-7 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 4-4. Total Uses for Potable and Non-Potable Water – Projected (DWR Table 4-2 Retail)

4.2.3.2 SRWA
Projected wholesale water demands from SRWA to the Cities are provided in Table 4 -5 (DWR Table 4-2 Wholesale). The projected water use in Table 4 -5 (DWR Table 4 -2 Wholesale) includes only SRWA’s projected surface water sales to the Cities (i.e., the Cities’ projected groundwater use is not included). SRWA also uses some potable water for on-site use at the WTP; however, the quantity of water is negligible.

As shown, SRWA’s water sales to the Cities of Turlock and Ceres are anticipated to increase through 2050 to approximately 4,752 MG and 1,939 MG, respectively, for a total of 6,691 MG. The projected wholesale water demands for SRWA are based on projections provided by the Cities. Actual water use from SRWA will depend on water year conditions, as SRWA’s supplies are anticipated to be reduced during drought years, in which case, the Cities will increase groundwater production to make up the difference.

Turlock has developed surface water use projections for the next ten years, through Water Year 2036–37 (i.e. April 1, 2036 through March 31, 2037) , which were incorporated into Table 4 -5 (DWR Table 4-2 Wholesale). Surface water demands beyond 203 6 were estimated using an assumed annual increase in surface water use of 2.6 percent . Wholesale demand projections will continue to be refined in future UWMP updates based on changes in retail demand and other conditions.

Consistent with the Ceres 2025 UWMP, Ceres’ projected surface water use is estimated assuming that two-thirds of Ceres' total projected demand is met by SRWA surface water. Buildout for the City of Ceres is projected to occur by 2045.

Use Type
Drop down list
May select each use multiple times
These are the only Use Types that will be
recognized by the WUEdata online
submittal tool
Potable or Non-Potable
(OPTIONAL)
Drop down list
2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 opt (MG)
Single Family See note (a). Potable 2,803 3,107 3,412 3,716 4,021 Multi-Family Potable 709 786 863 940 1,017
Commercial Potable 569 631 693 754 816
Industrial Potable 1,498 1,661 1,824 1,986 2,149
Landscape Potable 371 412 452 492 533
Other (optional) City meters (non-billed) Potable 167 185 203 221 240 Distribution System Water Loss Losses and unmetered water (e.g., flushing) Potable 778 863 947 1,032 1,116
Other (optional) Disinfected tertiary recycled
water. See note (b). Non-Potable 376 376 376 376 376
Landscape Non-potable raw water
irrigation wells at City parks Non-Potable 104 104 104 104 104 6,895 7,644 8,393 9,142 9,892
480 480 480 480 480
7,375 8,124 8,873 9,622 10,372
Submittal Table 4-2 Retail: Total Uses for Potable, and Non-Potable Water — Projected Water Code Section 10631(d)(1)
Projected Water Use
(Report To the Extent that Records are Available)
Additional Description
(as needed)
NOTES:
(a) Volume of water exported to City of Modesto is combined with the Single Family water use type in this table, as it is assumed, per Turlock's 2025 WMP, that Turlock will eventually acquire and serve the County enclaves that are currently served by City of Modesto. Actual timing is unknown. (b) Recycled water use shown includes only recycled water delivered within Turlock's service area. This volume includes recycled water delivered to TID's Walnut Energy Center for cooling, and a small amount of fill station use (<1 MG). Refer to Chapter 6 for additional detail on recycled water use.

Total
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

Subtotal Non-Potable
Subtotal Potable

Chapter 4
Water Use Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
4-8 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 4-5. Total Uses for Potable and Non-Potable Water – Projected (DWR Table 4-2 Wholesale)

SRWA does not serve non-potable water; therefore, no non-potable demands are shown.

4.2.4 Characteristic Five-Year Water Use
Water Code §10635(b) requires urban suppliers to include a five -year drought risk assessment (DRA) in their UWMP s. A key component of the DRA is estimating water demands for the next five years (2026-2030) without drought conditions (i.e., unconstrained demand). Chapter 7 details the DRA, but the five-year demand projections for Turlock and SRWA are summarized in the following sections.

4.2.4.1 City of Turlock
Table 4-6 shows Turlock’s five-year demand projections (2026-2030) for its DRA. Turlock’s projected water demands for 202 6 through 202 9 were estimated as a linear interpolation between the actual 2025 consumption by use type, reported in Table 4-2 (DWR Table 4-1 Retail), and the 2030 projected water use, reported in Table 4-4 (DWR Table 4-2 Retail).

Use Type
Drop down list
May select each use
multiple times
These are the only Use
Types that will be
recognized by the WUEdata
online submittal tool.

Potable or Non-
Potable
(OPTIONAL)
Drop down list
2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 opt
(MG)
Sales to other agencies City of Turlock. See note (a). Potable 2,837 3,316 3,772 4,288 4,752 Sales to other agencies City of Ceres. See note (b). Potable 1,485 1,623 1,773 1,939 1,939 4,322 4,939 5,545 6,227 6,691
0 0 0 0 0
4,322 4,939 5,545 6,227 6,691
NOTES:
(a) Turlock has projected its surface water use for the next ten years, through Water Year 2036-2037. For the purposes of this UWMP, projections beyond 2037 were estimated using an assumed annual increase in surface water use of 2.6 percent. (b) Ceres' projected surface water use is consistent with the Ceres 2025 UWMP and assumes that two-thirds of Ceres' total projected demand is met by SRWA surface water. Ceres buildout is projected to occur by 2045.

DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

Total
Projected Water Use (Report To the Extent that Records are Available) Subtotal Potable
Subtotal Non-Potable
Additional Description
(as needed)

Chapter 4
Water Use Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
4-9 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 4-6. Turlock’s Projected Five-Year Potable Water Use for Retail Customers, MG Water Use Sector 2026 2027 2028 2029 2030
Single Family 2,430 2,521 2,613 2,705 2,797
Multi-Family 587 618 648 678 709
Commercial(a) 477 500 523 546 569
Industrial 1,303 1,352 1,401 1,449 1,498
Landscape 286 307 329 350 371
Other - City meters (non-billed) 124 135 146 156 167
Sales/Transfers/Exchanges –
Exported to City of Modesto 5 5 6 6 6
Distribution System Water Loss 1,083 1,007 931 854 778
Total 6,295 6,445 6,595 6,745 6,895
(a) Commercial water use includes public and institutional land uses, consistent with Turlock’s annual reporting.

4.2.4.2 SRWA
Table 4-7 shows SRWA’s five-year wholesale demand projections (2026-2030) for its DRA, which are based on projected surface water use provided by the Cities . Actual water sales may vary due to hydrologic conditions and are dependent on the Cities’ finalized surface water orders for each water year. SRWA’s surface water orders are typically reported by water year (April through March); however, for consistency with reporting in this Joint UWMP, the values presented below have been approximated to a calendar year format.

Table 4-7. Projected Five-Year Potable Water Use for SRWA's Wholesale Customers, MG Customer Use Type 2026 2027 2028 2029 2030
City of Turlock(a) Sales to Other
Agencies 2,207 2,366 2,517 2,672 2,837
City of Ceres(b) Sales to Other
Agencies 1,452 1,442 1,433 1,459 1,485
Total 3,659 3,808 3,950 4,131 4,322
(a) Based on Turlock’s most recent surface water use projections, provided March 27, 2026. (b) Ceres' projected surface water use through 2030 is consistent with the Ceres 2025 UWMP and assumes that two-thirds of Ceres' total projected demand is met by SRWA surface water.

4.2.5 Estimating Future Water Savings
Turlock’s water use projections presented in Table 4-4 (DWR Table 4 -2 Retail) are based on projected future land use and area -based water use factors from its 2025 WMP. In accordance with the 2012 Turlock GP, water conservation is encouraged within the City. Urban water suppliers may consider the passive savings from codes, standards, ordinances, or transportation and land use plans. Such water savings decrease the water use projections for new and future customers compared to historical customers. As indicated in Table 4-8 (DWR Table 4-3 Retail), to be conservative, these potential passive savings have not been included in Turlock’s water demand projections.

Chapter 4
Water Use Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
4-10 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

While retail suppliers are required to estimate future water savings for this plan, this requirement does not apply to wholesale suppliers like SRWA, as they do not directly control or influence the water demands of its customers (i.e. the Cities).

Table 4-8. Inclusion in Water Use Projections (DWR Table 4-3 Retail)

4.2.6 Water Use for Lower Income Households
This UWMP considers current adopted codes, plans, and other policies or laws to estimate water savings projections. As indicated in Table 4‑8 (DWR Table 4 -3 Retail) , projected water use for lower income households in Turlock’s water service area are included in Turlock’s citywide water use projections.

A lower income household is considered to be a household with an income below 80 percent of an area median income (AMI), adjusted for family size. Projected water demands for lower income, single family, and multi-family residential water uses are included in the total water demands described in Section 4.2.3.

Turlock’s Revised Draft 2023-2031 Housing Element Update from November 2025 includes the number of existing lower income households, which includes Low Income (51 to 80 percent of AMI), Very Low Income (31 to 50 percent of AMI), and Extremely Low Income households (0 to 30 percent of AMI) . The Housing Element indicates that approximately 16 percent of Turlock’s existing households are Low Income , 13 percent are Very-Low Income, and 13 percent are Extremely-Low Income, for a total of 42 percent of households being lower income.3
Turlock assumes that lower income households will continue to represent approximately 42 percent of the City’s total residential customers through 2050 while recognizing that the percentage of lower income households is subject to change as demographic changes may occur. With this assumption, the projected

3 City of Turlock. November 2025. Revised Draft Housing Element Appendix B Housing Needs Assessment.

Table B-7: Turlock and Surrounding Areas Households by Household Income Level. Data is from U.S. Department of Housing and Urban Development, Comprehensive Housing Affordability Strategy ACS tabulation, 2016-2020 release.

Are Future Water Savings Included in Projections?
(Refer to Appendix K of UWMP Guidebook)
Drop down list (y/n)
No
If "Yes" to above:

State the section or page number, in the cell to the right, where citations of the codes, ordinances, or otherwise are utilized in demand projections are found.

OPTIONAL Suppliers may complete Optional Submittal Table 4-4 R to quantify the expected savings.

Are Lower Income Residential Demands Included In Projections? (Refer to Appendix K of UWMP Guidebook)
Drop down list (y/n)
Yes
OPTIONAL If the method for accounting Lower Income Residential Demands has been included, provide page number where this accounting can be found. (An example is included in Appendix K.)

Chapter 4
Water Use Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
4-11 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

water demand from lower income households will be approximately 2,122 MGY of residential water use by 2050.

4.3 DISTRIBUTION SYSTEM WATER LOSSES
System losses are the difference between the actual volume of water treated and delivered into the distribution system and the actual metered consumption. Such apparent losses are always present in a water system due to pipe leaks, unauthorized connections or use, faulty meters, unmetered services such as fire protection and training, and system and street flushing.

Turlock uses the AWWA Water Loss Audits and Loss Control Programs method to annually evaluate its distribution system losses. The water audit is an accounting exercise that tracks all sources and uses of water within a water system over a calendar year.

Table 4-9 (DWR Table 4-5 Retail) summarizes Turlock’s status in submitting its AWWA Water Loss Audits for the last five years starting in January 2020. Copies of Turlock’s water audit worksheets for the last five years are provided in Appendix F.

Table 4-9. Last Five Years of Water Loss Audit Reporting (DWR Table 4-5 Retail)

In November 2022, DWR and the State Water Board adopted water loss standards for urban retail water suppliers. The new regulation provides suppliers with volumetric standards that establish cost -effective levels of achievable water loss based on each supplier’s water system characteristics and budgets.

Beginning in January 2028, suppliers must meet their individual volumetric real loss standards based on a three-year compliance period of the Years 2025, 2026, and 2027. Individual apparent water loss standards must also be met at the same 2028 compliance date. Table 4-10 (DWR Table 4-6 Retail) summarizes the real and apparent water losses for 2025 compared to Turlock’s 2028 water loss standard.

Based on the most recent audit for Calendar Year 2024, Turlock’s real water loss and apparent water loss currently exceed the 2028 standard . However, Turlock will continue to implement water loss control measures to meet the standard by the 2028 compliance deadline. Turlock’s programs to assess and manage water loss are discussed further in Chapter 9.

As SRWA is a water wholesaler and not an urban retail water supplier, SRWA is not required to submit AWWA Water Loss Audits or meet water loss standards.

Public Water System ID #
Reported in Table 2-1 R Reporting Period Submitted to DWR Water Loss Audit Program (yes/no)
2020 Yes
2021 Yes
2022 Yes
2023 Yes
2024 Yes
CA5010019
DWR NOTES: Suppliers will provide a link to the WUEdata submittals of their Water Loss Audit Reports.
https://wuedata.water.ca.gov/awwa_plans
Report submittal status for all five years for each Public Water System as available. Add rows as needed

N-C-693-20-16-01-WP-Task 20-2025 UWMP
SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
April 2026

Table 4-10. Progress Towards 2028 Water Loss Standard (DWR Table 4-6 Retail)

Volume of Total Real
Loss (from AWWA
Water Loss Audit)
Volume of Total
Apparent Loss
(from AWWA Water
Loss Audit)
(MG)
(MG)
CA5010019 Yes 14.5
Gallons per Service
Connection per Day
(GPSCD)
20,053 913 124.8 18.6
Gallons per Service
Connection per Day
(GPSCD)
20,053 138 18.8
Number of Units
(Connections or Miles
corresponding with
units selected)
State Water Board Standard
2028 Real Water Loss
Standard per Unit per
day
Units for Real Water
Loss
Drop down list
State Water Board Standard
2028 Apparent Water
Loss Standard per Unit
per Day
Units for Apparent
Water Loss
Number of
Connections
NOTES: Number of service connections, total real loss, and total apparent loss are from the City of Turlock's 2024 AWWA Water Loss Audit, which is its most recent Water Loss Audit.

Apparent Water Loss
Did the Water Board
Calculate a Water Loss
Standard for this
Public Water System?
(y/n)
If no, Supplier will not
complete this row.

Real Water Loss
DWR NOTES: Units of measure (AF, CCF, MG) for Water Loss MUST remain consistent with units reported in Submittal Table 2-3. The units reported in Submittal Table 2-3 are used in this table's calculations.

Public Water
System ID #
Reported in
Submittal Table
2-1 R
Most Recent AWWA Water Loss Audit
Real Water Loss Per
Unit per Day
Most Recent AWWA Water Loss Audit
Apparent Water Loss
Per Unit per Day

Chapter 4
Water Use Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
4-13 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

4.4 CLIMATE CHANGE CONSIDERATIONS
Climate change has the potential to alter local climatic patterns and meteorology. This potential alteration may impact Turlock and SRWA’s future water demand and use patterns. In general, climate change is expected to increase water demand for irrigation and increase the year-to-year variability of demands. This increase in demands is the result of increased temperatures (which increases evapotranspiration) and more variability in precipitation (which impacts supply availability and reliability). Also, natural disasters such as wildfires, droughts, and floods are expected to increase in both frequency and intensity. The water demand projections developed in this Joint 2025 UWMP account for these anticipated increases.

Current and ongoing demand management measures and water conservation by Turlock and SRWA’s water customers, discussed in Chapter 9, could mitigate the effects of climate change on water demands.

Turlock and SRWA will continue to monitor the impacts of climate change on its water demands and on regional groundwater and surface water conditions. Updated climate and hydrologic information will be incorporated into future UWMP updates. The potential impacts of climate change on Turlock and SRWA’s water supplies are described in Chapter 6.

N-C-693-20-16-01-WP-Task 20-2025 UWMP
5-1 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

CHAPTER 5
SB X7-7 Baselines, 2020 Targets, and 2025 Reporting
In November 2009, SB X7-7, the Water Conservation Act of 2009, was signed into law as part of a comprehensive water legislation package. The Water Conservation Act addressed both urban and agricultural water conservation. The legislation set a goal of achieving a 20 percent statew ide reduction in urban per capita water use by December 31, 2020 (i.e., “20 by 2020”). In order to meet the urban water use target requirement, each retail supplier was required to determine its baseline water use, as well as its target water use for the year 2020. Water use is measured in gallons per capita per day (GPCD).

This chapter provides a review of the calculation of Turlock’s 2020 Urban Water Use Target and demonstrates that Turlock has achieved its 2020 target reduction.

Since SRWA is a water wholesaler and does not serve urban water users directly, it is not required to establish and meet any water conservation targets associated with the Water Conservation Act of 2009.

However, SRWA fully supports its water retailers in achieving their water conservation targets. A discussion of SRWA’s programs and policies for water conservation is provided in Chapter 9 Demand Management Measures (DMMs).

Turlock, as a water retailer, is required to report its compliance with the 2020 urban water use target as of 2020. The 2020 urban water use target has since been superseded by the establishment of Urban Water Use Objectives (UWUO) as part of the Making Conservation a California Way of Life regulation adopted on July 3, 2024. Starting in 2024, Turlock’s UWUO is calculated and reported annually through a separate process, and therefore, Turlock does not compare its 2025 water use with its 2020 target. Additional information on Turlock’s water conservation practices and objectives is included in Chapter 9.

5.1 OVERVIEW AND BACKGROUND
The City of Turlock’s compliance with SB X7-7 was first addressed in its 2010 UWMP. Turlock’s baseline per capita water use was determined, and urban water use targets for 2015 and 2020 were established and adopted. Actual water use data and population estimates were used to calculate GPCD water use.

SB X7-7 required each urban water retailer to determine its baseline daily per capita water use over a 10-year or 15-year baseline period. In its 2010 UWMP, the 10-year baseline period that Turlock selected was verified to be 199 7 through 200 6. Turlock calculated its baselines and water use targets on an individual reporting basis in accordance with SB X7-7 legislation requirements and DWR Methodologies for Calculating Baseline and Compliance Urban Per Capita Water Use (2016) (DWR Methodologies).

Details of the specific methodology used to calculate Turlock’s 2020 water use target are documented in its 2020 UWMP.

5.2 2020 DAILY PER CAPITA WATER USE COMPLIANCE
In its 2020 UWMP, Turlock calculated its actual 2020 water use for the 2020 Calendar Year in accordance with the DWR Methodologies document. As shown in Table 5-1 (DWR Table 5-1 Retail), urban per capita water use in 2020 was 250 GPCD, which is below the confirmed 2020 water use target of 284 GPCD.

Therefore, Turlock met its 2020 final water use target. Water use in 2020 in Turlock’s service area was reduced as compared to baseline years as a result of increased water conservation efforts by Turlock and its customers.

Chapter 5
SB X7-7 Baselines, 2020 Targets, and 2025 Reporting

N-C-693-20-16-01-WP-Task 20-2025 UWMP
5-2 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 5-1. SB X7-7 2020 Target Progress (DWR Table 5-1 Retail)

5.3 REGIONAL ALLIANCE
Turlock has chosen to comply with the requirements of SB X7-7 on an individual basis. Turlock has elected not to participate in a regional alliance.

Actual 2025 GPCD
(From SB X7-7
Compliance Form)
Did Supplier meet
the 2020 Target in
2025?
No Individual
Target 284 250 Yes NA
Did Supplier
Achieve Targeted
Reduction for
2020?
Actual 2020
GPCD2020 Target
Regional
Alliance Target
or Individual
Target?
Drop down list
DWR NOTES:

Suppliers calculating a 2025 GPCD will need to complete and submit SB X 7-7 Compliance Tables to verify the use of SB X7-7 Methodologies.

Suppliers that were part of a merger or consolidation since 2020 see Chapter 5 and Appendix P for guidance.

NA=Not Applicable
Check the box if the Supplier was not an Urban Water Supplier during or before the 2020 UWMP reporting cycle.

Proceed to the next table.

Only for suppliers that did not meet
the Target in 2020
See DWR NOTES below.

Was Supplier part of
a merger or
consolidation since
2020?

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-1 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

CHAPTER 6
Normal-Year Water Supply Characterization
This chapter characterizes Turlock and SRWA’s water supply portfolio. Currently available water supplies, as well as future anticipated water supplies, are described and quantified. The management of each water supply is discussed, along with the measures that Turlock and SRWA have taken to develop additional water supplies.

Turlock and SRWA’s existing water supply facilities are described in Chapter 3 of this Joint UWMP.

Turlock’s water supplies consist of the following:
• Groundwater pumped from Turlock-owned and operated wells • Treated surface water purchased from SRWA conveyed from the Tuolumne River through SRWA’s WTP
• Recycled water from Turlock’s Regional Water Quality Control Facility (RWQCF) Anticipated availability of Turlock and SRWA’s water supplies under a normal water year is provided in this chapter. A n ormal water year is defined in this UWMP as years when no regional or statewide drought declaration are in effect. The availability of Turlock and SRWA’s water supplies under a single dry year and a drought lasting five years are described in detail in Chapter 7 of this UWMP, along with the basis of those estimates.

Information for this chapter is from multiple sources including Turlock’s 2020 UWMP and 2025 WMP, SRWA’s 2020 UWMP (finalized in October 2024), the City of Ceres 2025 UWMP and WMP, and the 2024 Turlock Subbasin GSP)

6.1 OVERVIEW OF WATER SUPPLIES
The Cities formed the SRWA as a Joint Powers Authority in 2011 to provide a diversified and sustainable water supply portfolio. Historically, both Cities relied solely on groundwater from the Turlock Subbasin, which had become less reliable due to both the decline in water quality and the increasing number of regulated contaminants. SRWA evaluated various water supply options and identified the Tuolumne River as a viable surface water source that could be used in conjunction with the Cities’ existing groundwater supplies to provide a long-term, reliable drinking water supply for both Cities.

SRWA, in partnership with TID, developed the RSWSP (or Project) to divert, treat, and deliver drinking water to the Cities. The Project began delivering surface water to both Cities in November 2023. SRWA currently provides water supply to two wholesale customers: Turlock and the City of Ceres. Both Cities use a combination of surface water from SRWA and local groundwater from their respective city-owned groundwater wells to meet potable water demands. SRWA does not supply groundwater or any other water source.

SRWA uses surface water supplies entirely from the Tuolumne River via a long-term transfer agreement with TID using TID’s pre-1914 appropriative rights. This Agreement between SRWA and TID, included in Appendix E, defines the terms and conditions for the transfer and delivery of Tuolumne River water to SRWA. Under dry year conditions, TID may reduce surface water allocations to SRWA and its other customers. In these cases, SRWA will provide the maximum available surface water to the Cities based on TID’s allocation, and the Cities will pump groundwater to supplement the surface water supply to meet their total water demands.

Chapter 6
Normal-Year Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-2 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Under severe drought conditions, with reduced surface water allocations, SRWA may consider purchases or short-term transfers with other Tuolumne River water right holders, if necessary, to meet its customers’ potable water demands. However, the Cities anticipate maintaining adequate groundwater well capacity to meet water demands that are not met with surface water from SRWA.

SRWA does not anticipate using any other water supply sources such as groundwater, stormwater, recycled water, or desalinated water currently or in the future. Turlock, however, will continue to use groundwater and recycled water to meet potable and non-potable water demands.

6.2 GROUNDWATER
As described in Chapter 3, Turlock has 15 active potable groundwater wells throughout its service area.

Turlock also has four non-potable wells used for irrigation which are not connected to Turlock’s potable water system . Turlock’s total supply capacity for its active potable wells is 3 1.9 MGD.1 Prior to 2023, groundwater was Turlock’s sole water supply source. Turlock now uses its groundwater supplies conjunctively with purchased surface water from SRWA.

SRWA does not currently utilize, nor has plans to utilize, groundwater as a water supply. While SRWA does not utilize groundwater as a water supply, the Cities may deliver groundwater to TID on behalf of SRWA as offset water during dry years as part of SRWA’s Agreement with TID. At the time of development of this Joint UWMP, the Cities have not delivered any groundwater to TID on behalf of SRWA.

The local groundwater source is the Turlock Subbasin, which is a subunit of the San Joaquin Valley Groundwater Basin. Turlock has partnered with other groundwater users throughout the Turlock Subbasin to responsibly manage the Subbasin. The Turlock Subbasin is discussed in detail in the July 2024 Turlock Subbasin GSP. Further information on Turlock’s groundwater characteristics relevant to th is Joint 2025 UWMP is described in the following sections.

6.2.1 Subbasin Description
The Turlock Subbasin (DWR Subbasin 5-22.03) lies on the north-eastern side of California’s San Joaquin Valley and encompasses portions of both Stanislaus and Merced counties. The Subbasin is bounded by the Tuolumne River on the north, the Merced River on the south, and the San Joaquin River on the west, covering about 348,160 acres (about 544 square miles).

The Subbasin extends from the Sierra Nevada foothills to the San Joaquin Valley floor, with ground surface elevations sloping to the southwest and ranging from approximately 450 feet above mean sea level (msl) in the eastern foothills to less than 50 feet msl along the San Joaquin River. The western Subbasin is relatively flat with a uniform slope, and transitions to hummocky, irregular hills and intervening depressions in the eastern Subbasin.

Three principal aquifers have been defined in the Turlock Subbasin. The Corcoran Clay, underlying the western Subbasin, is the primary aquitard in the Subbasin separating the three principal aquifers, which include: the Western Upper Principal Aquifer (unc onfined above the Corcoran Clay), the Western Lower Principal Aquifer (confined below the Corcoran Clay), and the Eastern Principal Aquifer (unconfined to

1 City of Turlock, Carollo. March 2025. Water Master Plan. Values have been updated since the Water Master Plan to exclude Well 36, which is now inactive.

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semi-confined east of the Corcoran Clay). The extent of the Corcoran Clay in the western Subbasin ranges from depths of 90 to 240 feet below the ground surface and varies in thickness from 10 feet to 110 feet.

All three principal aquifers are used for water supply, with most water systems concentrated in the Western Upper Principal Aquifer and Western Lower Principal Aquifer, including the Cities, Hilmar, Delhi, and Keyes. Hughson, Hickman, parts of Denair, and other small water systems generally rely on the Eastern Principal Aquifer for water supply.

The Western Lower Principal Aquifer (confined below the Corcoran Clay) provides extensive municipal and agricultural supplies to water users in the Turlock Subbasin. Many of the cities and urban communities (e.g., Turlock, Ceres, Delhi, Hilmar, and Keyes) rely primarily on groundwater wells within the confined aquifer. Wells greater than 200 feet deep in the western Subbasin generally draw from the confined aquifer but also may receive flow from the unconfined aquifer.

In general, groundwater flows toward the west and southwest across the Subbasin, but flows are altered locally by pumping from wells. Vertical groundwater flow within the extent of the Corcoran Clay is downward, from the Western Upper Principal Aquifer to t he Western Lower Principal Aquifer.

Groundwater elevations in the Western Upper Principal Aquifer have been relatively stable during the GSP study period (Water Year 1991 through 2015) , with declines during the recent drought of less than 15 feet, followed by water level recovery. Water level declines during the 2015 drought were greater in the Eastern Principal Aquifer, especially in agricultural areas in the central and eastern Subbasin where groundwater is the primary water supply.

6.2.2 Groundwater Subbasin Management
In 2014, the California legislature enacted the SGMA in response to continued overdraft of California’s groundwater resources. With a goal to achieve sustainable management of groundwater basins , the legislation required the formation of GSAs and the development and implementation of GSPs for groundwater basins that are designated by DWR as medium or high priority. The Turlock Subbasin is not adjudicated2 and is not critically overdrafted. However, the Subbasin is identified as high priority by DWR.

As a high priority and non -adjudicated basin, the Subbasin was required to prepare and implement a GSP. Two GSAs were formed in the Subbasin. The West Turlock Subbasin Groundwater Sustainability Agency (WTSGSA) is located in the western Subbasin and covers about 60 percent of the area. The East Turlock Subbasin Groundwater Sustainability Agency (ETSGSA) cove rs the remaining 40 percent of the Subbasin in the east. The two GSAs cooperatively developed the Turlock Subbasin GSP to cover the entire Turlock Subbasin.

The GSAs are responsible for achieving long -term sustainable management of the Turlock Subbasin and must achieve sustainable groundwater management by 2042. As required by SGMA, the Turlock Subbasin GSP addresses measures necessary to attain sustainable conditions in the Subbasin. Sustainability is generally defined as long -term reliability of the groundwater supply and the absence of undesirable results, frequently caused by over-pumping.

2 Meaning that there is no court-appointed “watermaster” to resolve groundwater pumping issues, and there are no current specific required limits on the amount of groundwater that individuals and agencies may extract from the basin.

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The WTSGSA is composed of ten member agencies: Turlock , City of Ceres, Hughson, Modesto, Merced County, Stanislaus County, Denair Community Services District, Delhi County Water District, Hilmar County Water District, and TID. The WTSGSA also has two associate member agencies: Keyes Community Services District, and the City of Waterford, which is located in the Modesto Subbasin to the north but operates the water system for the community of Hickman in the Turlock Subbasin. The ETSGSA includes five member ag encies: Eastside Water District, Merced Irrigation District, Ballico -Cortez Water District, Merced County and Stanislaus County.

Figure 6 -1 shows approximate service areas within the Turlock Subbasin for the GSA member (and associate member) agencies. The Subbasin is organized into District and Non -District areas. The two counties within the Subbasin, Stanislaus County and Merced County, are shown as the member agencies in Non-District areas.

The Turlock Subbasin GSP was submitted to DWR on January 28, 2022. The Final Revised GSP was submitted to DWR on July 12, 2024. On Feb ruary 27, 2025, DWR approved the Turlock Subbasin’s GSP.

The Turlock Subbasin GSP is available at this website: https://turlockgroundwater.org/gsp, and is incorporated herein by reference.

Source: WTSGSA/ETSGSA, Todd Groundwater. July 2024. Turlock Subbasin GSP. Figure ES-2.

Figure 6-1. Jurisdictional Boundaries in Turlock Subbasin

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6.2.3 Subbasin Sustainable Yield
The Turlock Subbasin GSP developed an estimate of the Subbasin’s sustainable yield. Sustainable yield is defined for SGMA purposes as “the maximum quantity of water, calculated over a base period representative of long -term conditions in the basin and including any temporary surplus, that can be withdrawn annually from a groundwater supply without causing an undesirable result.” Sustainable yield for the Subbasin was estimated through development of a C2VSimTM scenario in which the long -term (50-year) SGMA sustainability indicators are met either directly or by groundwater levels as a proxy.

Table 6-1 provides a detailed listing of the water flow components of the Subbasin’s groundwater system across the historical, projected future, and sustainable yield conditions. Table 6-1 also shows the historical annual groundwater pumping, projected future groundwater pumping, and groundwater pumping under projected sustainable yield conditions. Future projections for urban groundwater production are based on 2015 UWMP projections for future buildout of the urban communities within the Subbasin.

As shown in Table 6-1, the Subbasin’s sustainable yield (i.e. groundwater production) was calculated to be 310,700 AFY. With additional data and information from the GSP’s on-going groundwater monitoring programs, the sustainable yield estimate is anticipated to continue to be refined and may be updated in the five-year GSP update in 2027. For comparison, the historical average annual groundwater pumping between Water Year (WY) 1991 through 2015 was estimated to be approximately 404,400 AFY (per Table 6-1). Therefore, historical annual groundwater use has exceeded the Subbasin’s sustainable yield estimate by approximately 94,000 AFY.

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Table 6-1. Sustainable Yield Average Annual Water Budget – Turlock Subbasin, AFY Component
Hydrologic Period
Historical Conditions
from WY 1991-2015
Projected Conditions
Hydrology from
WY 1969-2018
Sustainable
Conditions
Hydrology from
WY 1969-2018
Stream Seepage 61,500 109,400 82,700
Seepage from the Merced River 35,400 64,600 48,100
Seepage from the Tuolumne River 20,200 34,500 28,400
Seepage from the San Joaquin River 5,900 7,300 6,200
Canal & Reservoir Recharge 78,500 85,400 85,300
Deep Percolation 280,50 252,700 243,900
Subsurface Inflow 112,900 110,300 82,800
Flow from the Sierra Nevada Foothills 2,200 2,100 2,100 Merced Subbasin Inflows 58,700 59,500 32,700
Modesto Subbasin Inflows 35,600 34,300 29,500
Delta Mendota Subbasin Inflows 16,400 14,400 18,500
Total Inflow 533,400 557,800 494,700
Discharge Stream 118,100 71,000 91,600
Discharge to the Merced River 18,100 4,300 7,000
Discharge to the Tuolumne River 55,600 31,300 44,600
Discharge to the San Joaquin River 44,400 35,400 40,000 Subsurface Outflow 74,800 80,300 79,000
Merced Subbasin Outflows 13,700 20,300 20,400
Modesto Subbasin Outflows 33,200 32,800 36,600
Delta Mendota Subbasin Outflows 27,900 27,200 22,000
Groundwater Production 404,400 414,100 310,700
Agency Ag. Groundwater Production 49,200 51,300 51,300
Private Ag. Groundwater Production 269,700 287,000 191,200 Urban Groundwater Production 55,500 75,800 68,200
Total Outflow 597,300 565,400 481,300
Change in Groundwater Storage -63,900 -7,600 13,400
Source: WTSGSA/ETSGSA, Todd Groundwater. July 2024. Turlock Subbasin GSP. Table ES-2.

6.2.4 Management Actions
The GSP outlines projects and management actions to achieve the sustainability goals for the Turlock Subbasin by 2042. Projects include direct groundwater recharge, in-lieu groundwater recharge, as well as projects to encourage water conservation and reduce groundwater demand.

As shown in Table 6-1, reduced agricultural groundwater use is needed to attain sustainable yield within the Subbasin. Meanwhile, urban groundwater production is anticipated to increase over time as urban communities within the Subbasin continue to grow. Nevertheless, Turlock continues to develop projects

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to reduce groundwater dependency and aid the Subbasin in meeting its sustainability goals. The Cities of Turlock and Ceres’ RSWSP with SRWA is a major in -lieu groundwater recharge project in the GSP which benefits the Subbasin by increasing the use of treated surface water and reducing municipal groundwater pumping.

6.2.5 Groundwater Quality
Turlock actively monitors water quality in all its wells to ensure that observed concentrations remain below the maximum contaminant levels (MCLs). Several active wells have treatment systems in place to remove various contaminants. Some prior wells have b een sealed and destroyed due to casing or pump failures, high sand production, or water quality issues. Turlock currently has 25 inactive wells, 15 of which have been destroyed or abandoned.3
Observed groundwater contaminants include arsenic, nitrate, and 1,2,3 -Trichloropropane (1,2,3 -TCP).

Wells with observed concentrations above 80 percent of the MCL are out of service but may operate on standby to meet peak demands. Turlock plans to install additional wellhead treatment systems onto some existing wells that have elevated contaminant levels to maintain adequate supply capacity. Turlock’s 2025 WMP provides additional details on planned wellhead treatment systems.

In addition to installing wellhead treatment systems to reduce contamination in these wells, Turlock’s diversification of supplies away from groundwater ( i.e., surface water purchased from SRWA) will help mitigate future groundwater quality degradation. Turlock’s groundwater supplies will continue to be an important asset to be used in conjunction with SRWA’s treated surface water, especially for dry years in which surface water allocations may be curtailed.

6.2.6 Groundwater Use – Past Five Years
The volume of groundwater pumped by Turlock for potable use over the past five years is summarized in Table 6-2 (DWR Table 6-1 Retail). Historically, the local groundwater basin provided all of Turlock’s potable water supply. However, since 2023 with the construction of SRWA’s WTP and associated Tuolumne River surface water deliveries, Turlock’s reliance on groundwater has been significantly reduced.

In 2025, Turlock pumped 4,042 MG from the groundwater basin for potable use , about 66 percent of Turlock’s total potable water production. In comparison, prior to purchasing surface water from SRWA, Turlock’s potable groundwater use in 2021 was 6,456 MG. Turlock also pumped some groundwater to irrigate City parks with separate non-potable irrigation wells.

There were no limitations or challenges for obtaining groundwater during the past five years, as the GSP has not imposed any groundwater pumping restrictions on Turlock or other urban groundwater users within the Subbasin.

As shown in Table 6-3 (DWR Table 6-1 Wholesale), SRWA does not pump groundwater.

3 State Water Resources Control Board. Safe Drinking Water Information System CA Drinking Water Watch Water System Details. City of Turlock. Accessed at
https://sdwis.waterboards.ca.gov/PDWW/JSP/WaterSystemDetail.jsp?tinwsys_is_number=5565&tinwsys_st_code=CA on March 30, 2026.

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Table 6-2. Groundwater Pumped in Last Five Years (DWR Table 6-1 Retail)

Table 6-3. Groundwater Pumped in Last Five Years (DWR Table 6-1 Wholesale)

6.2.7 Groundwater Use – Projected
Turlock plans to continue using groundwater as part of its conjunctive use strategy to meet peak potable demands and to offset anticipated reductions in surface water deliveries during dry years. Groundwater will remain a critical component of Turlock’s water supply portfolio, particularly during periods of surface water shortage.

Projected potable groundwater use for normal years through 2050 is presented in Table 6 ‑4. These projections represent the volume of groundwater required to meet total potable demand after accounting for projected surface water use, and are well within the Turlock GP policy for sustainable groundwater pumping rate.

Future potable groundwater use was estimated as the difference between Turlock’s projected potable demands (from Table 4-4 [DWR Table 4-2 Retail]) and Turlock’s projected surface water use (from Table 45 Groundwater Type
Drop Down List
May use each category
multiple times
Potable or
Non-Potable
(OPTIONAL)
Drop down list
Location or Basin Name 2021 (MG) 2022 (MG) 2023 (MG) 2024 (MG) 2025 (MG) Alluvial Basin Potable
Turlock Subbasin within the
San Joaquin Valley
Groundwater Basin
6,456 6,199 5,979 4,232 4,042
Alluvial Basin Non-Potable
Turlock Subbasin within the
San Joaquin Valley
Groundwater Basin
104 104 104 104 104
6,456 6,199 5,979 4,232 4,042
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

NOTES: Annual groundwater volume pumped is from the City of Turlock's Annual AWWA Water Loss Audits for all years but 2023. For 2023, the total groundwater production is based on data from the State Open Data Portal which was assumed to be more accurate, as described in Table 4-1. Non-potable irrigation well usage in 2021 through 2024 is estimated based on actual metered 2025 usage.

Total
Check the box if the Supplier does not pump groundwater.

Proceed to the next table.

Check the box if all or part of the groundwater described below is desalinated. (OPTIONAL) Groundwater
Type
Drop Down List
May use each
category multiple
times
Potable or Non-
Potable
(OPTIONAL)
Drop down list
Location or
Basin Name 2021 (MG) 2022 (MG) 2023 (MG) 2024 (MG) 2025 (MG) 0 0 0 0 0
Check the box if the Supplier does not pump groundwater.

Proceed to the next table.

Total
Check the box if all or part of the groundwater described below is desalinated. (OPTIONAL)

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[DWR Table 4 -2 Wholesale]). As population growth and water demand increase over time, both groundwater and surface water use are anticipated to increase. Turlock will continue to finetune its conjunctive use operations to optimize system efficiency, maintain cost effectiveness, and support sustainable management of the underlying groundwater basin.

Refer to Table 6-16 (DWR Table 6-9 Retail) for Turlock’s projected non -potable groundwater use through 2050.

Total projected water supplies available to meet Turlock’s future water demands are discussed further in Section 6.10. The availability of groundwater under single dry years and five-year droughts is discussed in Chapter 7.

Table 6-4 Projected Potable Groundwater Use for City of Turlock Groundwater Type
Location or
Basin Name
Projected Potable Groundwater Use, MG(a)
2030 2035 2040 2045 2050
Alluvial Basin
Turlock Subbasin within
the San Joaquin Valley
Groundwater Basin
4,058 4,328 4,621 4,854 5,140
(a) Turlock’s projected potable groundwater use is estimated as the difference between Turlock’s potable demand projections defined in Section 4.2.3.1 and Turlock’s projected surface water use defined in Section 4.2.3.2.

6.3 WATER EXCHANGES AND TRANSFERS
SRWA and TID entered into their Agreement on July 28, 2015 . The Agreement provides the terms and conditions under which SRWA may purchase up to 30,000 AFY ( equivalent to 9,776 MGY) of Tuolumne River surface water from TID. The Agreement does not transfer water rights from TID to SRWA . Instead, it allows transfers of water from TID to SRWA. TID maintains the water rights to all transfer water. The Agreement was amended in April 2020 to reflect some changed circumstances (e.g., approval of environmental documentation, updates on water right petition).

In 2018, TID filed a petition with the State Water Board for a long -term change to TID’s post -1914 appropriative water right (Water Right License 11058 (A014127)). With the petition, TID sought authorization to transfer post -1914 appropriative water to SRW A to implement the Agreement. Due to potential impacts to Don Pedro Reservoir operations, TID decided instead to solely transfer water from its pre-1914 appropriative rights to SRWA. Under CWC § 1706, TID, as a pre-1914 water right holder, may change the point of diversion, purpose of use, or place of use, if others are not injured by such change.

Therefore, SRWA receives only pre-1914 transfer water from TID.

To provide transfer water to SRWA, TID releases surface water previously stored in Don Pedro Reservoir at TID’s downstream La Grange diversion dam into the Tuolumne River . The surface water is then withdrawn approximately 26 miles downstream by an infiltration gallery in the Tuolumne River owned by TID and operated by SRWA . The point of delivery of transfer water to SRWA is at the delivery meter located at SRWA’s WTP.

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6.3.1 Surface Water Allocations
While SRWA can receive up to 30,000 AFY (9,776 MGY) of surface water from TID, actual water allocations to SRWA may be reduced by TID during dry years. Per the Agreement, TID treat s SRWA and TID’s agricultural customers on a parity basis. If TID determines the need to reduce deliveries at any time before or during a year, it will cut back its deliveries to its agricultural customers and to SRWA in equal proportions based upon the amount of water allocated during that year. If TID decides it can increase deliveries, it will increase its deliveries to its agricultural customers and to SRWA in equal portions based upon the amount of water allocated during that year.

The TID Board of Directors determines in February or March of each year, just prior to the start the irrigation season, whether water allocations to its customers will be reduced during that year based on various factors such as:
• projected runoff, which includes consideration of potential occurrence of consecutive dry years,
• carryover storage projections in Don Pedro Reservoir, and • instream flow requirements for the Tuolumne River.4
TID provides SRWA, on or before March 1 preceding each new water year, with a water delivery schedule for the upcoming water year beginning April 1. This schedule specif ies the monthly volumes of water to be delivered to SRWA during that water year. TID’s water year is defined as the period from April 1 through March 31 of the following year.

The Agreement states that TID’s commitments to SRWA and its agricultural customers shall be met before any subsequent transfers for delivery of water outside of TID’s boundaries, with the exception of transfers of water released pursuant to any agreement with the City and County of San Francisco and/or Modesto Irrigation District (MID) relating to minimum instream flow requirements.

For TID’s agricultural customers, the base water allocation, or full allocation, is 48 inches per acre. For SRWA, the base allocation is the amount of water requested by SRWA in the current year of the most recently-approved two -year delivery schedule . In dry years, SRWA’s base allocation will be reduced proportionately to TID’s agricultural customers as determined by the TID Board. Per TID’s 2020 AWMP, TID customers have received full water allocations in 16 of the last 29 years (through 2020). TID’s average agricultural allocation for the past 22 years (through 2020) is 11 percent below the full allocation (2020 AWMP).

In reviewing TID’s recent 15 years of allocations (2010 through 2024) , the average allocation has been 98 percent of full allocation during normal years (i.e., years without emergency drought orders). The reductions to be expected in a single dry year, and multiple dry years is discussed in Chapter 7.

6.3.2 Offset Water
In any year that TID’s allocation to agricultural users is less than 48 inches, SRWA is required to provide offset water to TID. This requirement is expected to occur during dry years when surface water supplies

4 TID. March 2021. 2020 Agricultural Water Management Plan.

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are limited. The Cities are responsible for providing the offset water to TID on behalf of SRWA during these dry years. The offset water is either non -potable groundwater from the Cities’ wells and/or tertiary treated recycled water from Turlock’s RWQCF.

The Agreement allows for improved operational flexibility for both the Cities and TID by reducing groundwater pumping during normal to wet years and relying on groundwater during dry years when surface water is limited. All offset water will be produced by city-owned facilities and delivered to TID via TID-owned conveyance infrastructure. Therefore, no SRWA facilities are currently used for the production or delivery of offset water.

6.4 SURFACE WATER
SRWA’s sole water supply source is surface water diverted from the Tuolumne River as described in Section 6.3. SRWA receives surface water from the Tuolumne River based on the long -term Agreement with TID using TID’s existing pre -1914 appropriative water right. TID maintains the water rights to all transfer water provided to SRWA; SRWA does not directly hold any s urface water rights on the Tuolumne River.

SRWA treats this surface water at its WTP and then distributes the treated surface water to the Cities. As per the Executed Regional Surface Water Supply Phase 3 Project Design and Construction Funding Agreement between SRWA and the Cities, an allocation based on a proportion of the WTP capacity is dedicated to each city, with two thirds dedicated to Turlock and one third dedicated to Ceres. The WTP’s current capacity is 15 MGD, of which 10 MGD is dedicated to Turlock and 5 MGD is dedicated to Ceres. When WTP expansions increase the WTP capacity, the allocations to the Cities will increase proportionally.

6.5 PURCHASED OR IMPORTED WATER
As discussed in Section 6.4, Turlock purchases treated surface water from SRWA in accordance with the Executed Regional Surface Water Supply Phase 3 Project Design and Construction Funding Agreement.

As discussed in Section 6.3, SRWA has an Agreement with TID for a long-term transfer to receive surface water from the Tuolumne River. SRWA does not currently purchase, nor have plans to purchase, any other water supplies. During severe drought conditions that significantly reduce SRWA’s surface water allocations from TID, SRWA may consider a purchase of water from other TID customers or a short -term transfer of surface water from other water right holders with pre-1914 appropriative water rights on the Tuolumne River. As discussed further in SRWA’s WSCP, this purchase would likely only be necessary if the Cities determine that they do not have sufficient well capacity to meet demands with groundwater during dry years with significantly reduced water allocations from TID.

6.6 STORMWATER
Turlock and SRWA do not currently utilize, nor have plans to utilize, stormwater as a water supply.

However, Turlock does use stormwater detention basins to recharge the local groundwater basin.

Turlock’s stormwater system includes about 130 miles of storm drain collection/conveyance piping, 49 pump stations, 45 detention basins, and use of the TID open channel irrigation system.

The majority of Turlock’s stormwater drains to local detention basins. Although the primary purpose of these detention facilities is for urban runoff and flood control, they passively contribute to groundwater recharge through percolation of stored supplies. These detention facili ties are managed in a way to

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maximize stored volume to maximize groundwater recharge as long as flood control concerns are low. As soon as wet weather events are in the forecast, the detention facilities are drained to create more space for stormwater detention.

A portion of Turlock’s stormwater drains to TID laterals. Although this drainage does not directly increase supply for Turlock, stormwater delivered to TID helps to offset TID water demands. Turlock works closely with TID to ensure adequate capacity is available in the laterals for stormwater discharges. Turlock implements best management practices to improve water quality for the stormwater discharges . The remainder of Turlock’s stormwater that is not captured in detention basins or flows to TID laterals eventually drains through a combined sewer system to the Turlock RWQCF.

Turlock completed the Dianne Storm Basin Project in 2023, which provides direct groundwater recharge to the Subbasin through the existing Dianne Storm Drain Basin. The project enhances infiltration and impoundment of stormwater in the storm basin during the wet season using dry wells and conveys Tuolumne River water from TID into the storm basin for recharge during the irrigation season in wet years.

The basin is located on the western edge of Turlock and north of the Turlock RWQCF, with a surface area of 26 acres and a capacity for approximately 105 AF. The basin receives stormwater from Fulkerth Road which accounts for roughly one third of the stormwater captured within Turlock.

Turlock plans to recharge stormwater into the basin during all years when water is available from storm events. In above normal and wet hydrologic years during the irrigation season, water from the Tuolumne River will be conveyed using existing infrastructure into the storm basin for direct recharge . Per the Turlock Subbasin GSP, approximately 22.5 AFY could be captured and recharged during the wet season and 400 AFY could be diverted and recharged from the Tuolumne River during the irrigation season in above normal and wet hydrologic years.

6.7 WASTEWATER AND RECYCLED WATER
Since 2006, Turlock has operated a disinfected tertiary wastewater treatment system, the Turlock RWQCF.

This section provides information on Turlock’s wastewater and its current and potential reuse as a recycled water resource.

SRWA does not collect or treat wastewater, nor does it distribute or use recycled water.

6.7.1 Recycled Water Coordination
The Cities of Turlock and Modesto worked together with the Del Puerto Water District (DPWD) to develop a cooperative project to regionalize recycled water use in Stanislaus County , the North Valley Regional Recycled Water Program (North Valley Program). Starting in December 2017, the North Valley Program began producing and delivering up to 30,600 AFY (9,970 MG Y) of disinfected tertiary treated recycled water to western Stanislaus County. By 2045, the North Valley Program could deliver up to 59,900 AFY (19,500 MGY) of recycled water. The source of recycled water includes treated wastewater from the Cities of Turlock and Modesto. As part of the project, Turlock installed 7.3 miles of conveyance pipeline to convey recycled water directly from its RWQCF’s tertiary treatment plant to the Modesto pumping facility, which then pumps the recycled water to the Delta-Mendota Canal (DMC). The DMC is used to convey the blended canal-recycled water to DPWD in the west side of the County.

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In addition to the regional North Valley P rogram, Turlock operates its own recycled water program for customers within Turlock’s service area. Turlock coordinates both internally and externally with its recycled water customers. Turlock also coordinates with businesses and residences in the surrounding geographic areas adjacent to and within Turlock.

6.7.2 Wastewater Collection, Treatment, and Disposal
Turlock’s RWQCF has a design daily average flow capacity of 20 MGD, although the current effective or permitted capacity is lower in order to ensure compliance with permit requirements. The RWQCF is currently treating an average influent flow of 10.7 MGD. The raw wastewater received at the RWQCF is a combination of domestic and industrial wastewater flows. Influent consists of wastewater from Turlock, Keyes Community Services District (CSD), Denair CSD, and up to 2 MGD of primary treated wastewater from the City of Ceres. The RWQCF produces disinfected tertiary treated water that meets Title 22 standards for unrestricted non-potable use pursuant to Title 22 section 60301.230(a)(1).

The RWQCF treatment system consists of influent screening, grit removal, primary flotation, secondary treatment (which consists of activated bio-filtration for biological oxygen demand (BOD)/total suspended solids (TSS) reduction and nitrification), secondary clarification, tertiary treatment (which consists of high rate clarification with chemical addition followed by cloth disk filters), disinfection via chlorination, and dechlorination by sodium bisulfite. Solids handling at the RWQCF consists of gravity belt thickening, two-stage anaerobic digestion via acid phase and methane phase digesters, and sludge drying beds.

Biosolids are beneficially reused for land application to farmland and co-compost.

Wastewater facilities also include a 37.2 MG earthen storage basin, allowing the emergency diversion and storage of flow when necessary. Constructed with a 6-inch bentonite liner on the bottom and sides, the basin can be used to store either excess wet wea ther influent, or effluent that does not meet permit requirements.

Since the North Valley Program was implemented in late 2017, Turlock only discharges a small amount of effluent to the San Joaquin River. Nearly all the RWQCF effluent is used as recycled water either by the North Valley Program or within Turlock’s service area (refer to Table 6-6 [DWR Table 6-3 Retail]). Prior to the implementation of the North Valley Program, effluent from the RWQCF that was not recycled within Turlock’s service area was discharged to the San Joaquin River. Turlock’s 36-inch diameter outfall facilities remain as a backup discharge location to the San Joaquin River.

6.7.2.1 Wastewater Collected Within Service Area
Table 6 -5 (DWR Table 6 -2 Retail) summarizes information on wastewater collection within Turlock’s wastewater service area. The volume of wastewater collected from Turlock, Keyes CSD, Denair CSD, and the City of Ceres is included in the volume presented in Table 6-5 (DWR Table 6-2 Retail) because flows are not metered separately.

Chapter 6
Normal-Year Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-14 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 6-5. Wastewater Collected Within Service Area in 2025 (DWR Table 6-2 Retail)

6.7.2.2 Wastewater Treatment and Discharge Within Service Area Table 6-6 (DWR Table 6-3 Retail) identifies the volume of treated wastewater recycled within or outside Turlock’s water service area. Most of the recycled water use occurs outside of Turlock’s water service area for agricultural irrigation as part of the North Valley Program. The volume shown in Table 6-6 (DWR Table 6-3 Retail) includes wastewater collected from both Turlock and from Keyes CSD, Denair CSD, and the City of Ceres.

As shown in Table 6-7 (DWR Table 6-3 Wholesale), SRWA does not treat or distribute wastewater.

Name of Wastewater
Collection Agency
Wastewater
Volume Metered
or Estimated?

OPTIONAL
Drop Down List
Volume of
Wastewater Collected
from UWMP Service
Area 2025 (MG)
Name of Wastewater Treatment
Plant (WWTP) and Place ID
Number
Drop down list
Is WWTP
Located Within
UWMP Area?
Drop Down List
City of Turlock Metered 3,902
Turlock City, Turlock Regional
Water Quality Control Facility,
Place ID 266737
Yes
3,902
Check the box if there is no wastewater collection system.

Proceed to the next table.

NOTES: Volume shown includes wastewater collected outside Turlock's water service area including the Keyes Community Service District (CSD), Denair CSD, and up to 2 MGD of primary treated wastewater from the City of Ceres, all of which is treated at Turlock's Regional Water Quality Control Facility. Metered wastewater volumes are based on WWTP influent flows, and data covering only Turlock's water service area is not available.

Percentage of 2025 service area population served by wastewater collection system (OPTIONAL)
Percentage of 2025 service area served by wastewater collection system (OPTIONAL) DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

Additional Guidance: See Appendix M, Section M.21 for detailed guidance on this table.

Wastewater Collection Recipient of Collected Wastewater Total Wastewater Received from UWMP
Service Area in 2025:

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-15 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 6-6. Wastewater Treatment and Outcomes Within Service Area in 2025 (DWR Table 6-3 Retail)

Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Name of
other
entity
Turlock City, Turlock
Regional Water
Quality Control
Facility, Place ID
266737
Yes 3,902 3,902 Tertiary 376 Tertiary 3,492 Tertiary 35 0 0 3,902 3,902 376 3,492 35 0 0
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

IPR: Indirect Potable Reuse would have the treatment level of its end use requirement in the Level of Treatment drop-down.

Additional Guidance: See Appendix M, Section M.21 for detailed guidance on this table.

Water Recycled
Outside of UWMP
Service Area
(enter data as applicable)
Effluent Discharge that
is not a Permitted
Recycled Water Use
(enter data as applicable)
Required Discharge for
Instream Flow
(enter data as applicable)
Delivered to Another Entity for
Additional Treatment
(enter data as applicable)
2025 Outcomes of Treated Wastewater
Check the box if no wastewater is treated or disposed of within the UWMP service area.

Proceed to the next table.

Does This
Plant Treat
Wastewater
Generated
Outside the
UWMP Service
Area?
(OPTIONAL)
Drop down list
Wastewater
Treatment Plant
Name and Place ID
Number
Drop down list
Total 2025
Volume of
Water
Treated
(MG)
NOTES: Volume shown includes wastewater collected outside Turlock's water service area including the Keyes Community Service District (CSD), Denair CSD, and up to 2 MGD of primary treated wastewater from the City of Ceres, all of which is treated at Turlock's Regional Water Quality Control Facility. Metered wastewater volumes are based on WWTP influent flows, and data covering only Turlock's water service area is not available.

Total
2025 Volume
of Wastewater
Received from
UWMP Service
Area
(As Reported
in Submittal
Table 6-2 R)
(MG)
Water Recycled
Within UWMP Service
Area
(enter data as applicable)

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-16 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 6-7. Wastewater Treatment and Outcomes Within Service Area in 2025 (DWR Table 6-3 Wholesale)

Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Treatment
Level
Drop down
list
Volume
(MG)
Name of
other
entity
0 0 0 0 0 0 0Total
Check the box if the Wholesale Supplier neither distributes nor provides supplemental treatment to recycled water.

Proceed to the next table.
2025 Volume
of Wastewater
Received from
UWMP Service
Area (MG)
2025 Outcomes of Treated Wastewater
Water Recycled
Within UWMP Service
Area
(enter data as applicable)
Water Recycled
Outside of UWMP
Service Area
(enter data as applicable)
Effluent Discharge that
is not a Permitted
Recycled Water Use
(enter data as applicable)
Required Discharge for
Instream Flow
(enter data as applicable)
Delivered to Another Entity for
Additional Treatment
(enter data as applicable)
Wastewater
Treatment Plant
Name and Place
ID Number
Drop down list
Does This Plant
Treat
Wastewater
Generated
Outside the
UWMP Service
Area?
(OPTIONAL)
Drop down list
Total 2025
Volume
of Water
Treated
(MG)

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-17 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

6.7.3 Recycled Water System Description
Although Turlock has operated an established recycled water program since 1990, it does not operate a large pipeline distribution system, and has instead opted to evaluate, design, and build facilities on a per connection basis.

Currently, Turlock provides up to 2.0 MGD of recycled water to TID’s Walnut Energy Center Co-Generation Facility for cooling, and a small amount of recycled water at a City -owned and operated fill station . The remaining recycled water is utilized by the North Valley Program for agricultural irrigation.

6.7.4 Potential, Current, and Projected Recycled Water Uses Uses of disinfected tertiary recycled water may include, but are not limited to: agricultural irrigation, water for industrial purposes (including process cooling water), residential landscape irrigation, construction water, and other uses as approved by Turlock identified within Title 22 California Code of Regulations.

Table 6-8 (DWR Table 6-4 Retail) shows Turlock’s current and projected recycled water uses through 2050.

Most recycled water is used for agricultural irrigation as part of the North Valley Program, with the second largest user currently being TID’s Walnut Energy Center Co -Generation Facility. These recycled water demands are expected to remain relatively constant through 2050.

Turlock’s landscape irrigation and recycled water fill station use represents a small amount of total recycled water use, generally totaling less than 1 MGY. Although in past years Pedretti Sports Fields received recycled water for irrigation, Turlock did not supply recycled water to the Pedretti Sports Fields in 2025, as Turlock’s non-potable wells can also provide irrigation water to these fields. Now that the North Valley Program is online, Turlock reserves the recycled water for that program while only using the recycled water to supplement the non -potable well water for irrig ation of the Pedretti Sports Fields when needed.

As part of SRWA’s Agreement with TID, SRWA will provide 2,000 AFY (652 MGY) of recycled water from Turlock to TID for agricultural irrigation purposes. Due to on -going discussions on recycled water conveyance between Turlock ’s RWQCF and TID ’s conveyance facilities , Turlock has not yet provided recycled water to TID and has instead been providing an in -lieu fee to TID. For the purposes of this plan, recycled water deliveries from Turlock to TID are assumed to begin by approximately 2028.

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-18 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 6-8. Current and Projected Recycled Water Uses Within Service Area (DWR Table 6-4 Retail)

Volume
Narrative
page
number
(OPTIONAL)
Agricultural irrigation Non-Potable
Transported by North Valley
Regional Recycled Water
Pipeline for agricultural
irrigation.

See note (a).
3,492 3,492 3,492 3,492 3,492 3,492 N/A
Agricultural irrigation Non-Potable
Recycled water delivered to
Turlock Irrigation District for
agricultural irrigation. See
note (b).
0 652 652 652 652 652 652
Landscape irrigation
(exc golf courses) Non-Potable Irrigation at Pedretti Sports Fields 0 1 1 1 1 1 1
Geothermal and other
energy production Non-Potable
Turlock Irrigation District's
Walnut Energy Center Co-
Generation Facility cooling
towers
376 376 376 376 376 376 N/A
Landscape irrigation
(exc golf courses) Non-Potable
Recycled Water Filling
Station.

See note (c).
<1 MG Varies,
<1 MG
Varies,
<1 MG
Varies,
<1 MG
Varies,
<1 MG
Varies,
<1 MG <1 MG
0 0 0 0 0 0 0
3,867 4,520 4,520 4,520 4,520 4,520 N/A
3,867 4,520 4,520 4,520 4,520 4,520 N/A 0
Check box if recycled water is not used and is not planned for use within the service area of the supplier. The supplier will only complete the column on "Potential Recycled Water Use" and submit an accompanying narrative on the feasibility of that potential recycled water use.

Potential Recycled
Water Use
Name(s) of Facility/ies Producing (Treating) the Recycled Water (OPTIONAL) : Turlock Regional Water Quality Control Facility, Place ID 266737 Name of Supplier Operating the Recycled Water Distribution System City of Turlock Volume of Supplemental Water Added in 2025 (OPTIONAL) :

Source of 2025 Supplemental Water (OPTIONAL) :

Total
Use Type
Drop down list
Potable or Non-
Potable
(after treatment if
treated)
(OPTIONAL)
Drop down list
Additional Information
(as needed)
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

Additional Guidance: See Appendix M, Section M.21 for detailed guidance on this table.

Potential recycled water use: a description of the feasibility of these uses must be included in the narrative.

Multiple Producers: If you have multiple recycled water producers, submit a separate table for each.

NOTES: (a) Volume of recycled water available for delivery to the North Valley Regional Recycled Water Program (North Valley Program) may vary, as wastewater and recycled water flow projections through 2050 are not available. Volume delivered to the North Valley Program may increase or decrease based on available recycled water supply in future years.
(b) Turlock anticipates beginning to deliver recycled water to TID for agricultural irrigation as part of the SRWA-TID Water Sales Agreement water in approximately 2028.
(c) The City began its recycled water filling station in 2018. Turlock has not set a limit on the amount of recycled water that can be trucked off-site other than 300 gallons per vehicle per trip. Total fill station use in 2025 was approximately 8,500 gallons, and fill station use is expected to continue to represent only a minor amount of Turlock's overall recycled water use.
(d) Due to rounding, the volumes by individual use shown in the table may not sum exactly to the subtotals or totals. 2050 (MG)2025 (MG) 2030 (MG) 2035
(MG)
2040
(MG)
2045
(MG)
Subtotal Potable
Subtotal Non-Potable

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-19 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 6-9 (DWR Table 6-5 Retail) shows a comparison between the recycled water use that was projected in Turlock’s 2020 UWMP for 2025 and the actual recycled water use for 2025.

Actual recycled water use at the Walnut Energy Center cooling tower was slightly higher than projected, while uses for agricultural irrigation through the North Valley Program and landscape irrigation at the Pedretti Sports Fields were lower than projected in the 2020 UWMP. Recycled water use for agricultural irrigation is influenced by the available recycled water supply and wastewater flows, and any additional supply would be delivered to the North Valley Program. Recycled water use at the Pedretti Sports Fields was less than previously projected since Turlock’s non -potable wells can also provide irrigation water to these fields.

Overall, total recycled water use in 2025 was approximately five percent less than projected in Turlock’s 2020 UWMP.

Table 6-9. 2020 Recycled Water Use Projection Compared to 2025 Actual (DWR Table 6-5 Retail)

As shown in Table 6 -10 (DWR Table 6 -4 Wholesale) and Table 6 -11 (DWR Table 6 -5 Wholesale), SRWA does not use or distribute recycled water, nor does SRWA plan to do so.

Table 6-10. Current and Projected Recycled Water Uses (DWR Table 6-4 Wholesale)

2020 Projection for
2025 (MG)
2025 Actual Use
(MG)
3,755 3,492
1 0
301 376
Varies <1 MG
4,057 3,867
Other (Description Required)
Check the box if recycled water was not used in 2025 nor previously projected for use in 2020.

Proceed to the next table.

Agricultural irrigation
NOTES: (a) The "Other" use type is Turlock's recycled water filling station.

Total
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure reported in Submittal Table 2-3 Additional Guidance: See Appendix M, Section M.21 for detailed guidance on this table.

Use Type
Drop Down list
Landscape irrigation (exc golf courses)
Geothermal and other energy production
Volume Narrative page number
(OPTIONAL)
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0 0Total
Name of Receiving
Supplier or Direct
Use by Wholesale
Supplier
Potable or Non-Potable
(after treatment if
treated)
(OPTIONAL)
Drop down list
Additional
Information
(as needed)
Check box if recycled water is not used and is not planned for use within the service area of the supplier. The supplier will only complete the column on "Potential Recycled Water Use" and submit an accompanying narrative on the feasibility of that potential recycled water use.

Potential Recycled Water Use
2050
(MG)
2025
(MG)
Subtotal Potable
Subtotal Non-Potable
2030
(MG)
2035
(MG)
2040
(MG)
2045
(MG)

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-20 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 6-11. 2020 Recycled Water Use Projection Compared to 2025 Actual (DWR Table 6-5 Wholesale)

6.7.5 Actions to Encourage and Optimize Future Recycled Water Use Turlock has plans for encouraging and expanding future recycled water use in its service area. These plans are discussed in the following sections and summarized in Table 6-12 (DWR Table 6-6 Retail).

6.7.5.1 Expansion of Recycled Water to TID for Agricultural Irrigation As part of SRWA’s Agreement with TID, SRWA will provide 2,000 AFY (652 MGY) of recycled water from Turlock to TID for agricultural irrigation purposes. Due to on -going discussions on recycled water conveyance between Turlock and TID, Turlock has not yet provided recycled water to TID for agricultural irrigation and has instead been providing an in-lieu fee to TID. For the purposes of this plan, recycled water deliveries from Turlock to TID is assumed to begin in 2028.

6.7.5.2 Outreach for Recycled Water for Residential and Commercial Filling Stations Since 2018, recycled water has been available to commercial and residential users through an on -site filling station at Turlock’s RWQCF. Users can fill properly identified recycled water tanks in their vehicle for appropriate uses off-site. Residential users may fill up to a maximum volume of 300 gallons per visit.5 To prevent cross -contamination, all portable recycled water containers are prohibited from being connected to any potable water supply system. Additionally, commercial users are required to maintain a logbook detailing the date of delivery, name and address of delivery/recipient, type of use, volume delivered/used and intended use of water delivered. The quantity of recycled water provided by this filling station was approximately 8,500 gallons, thus representing a minor amount of the City’s total recycled water use.

Turlock plans to continue conducting outreach regarding the availability of recycled water and encouraging the use of it to reduce the use of potable water for end uses that could be satisfied with non- potable water. Turlock will also continue to offer recycled water to contractors for construction use via the fill station. As these on-going efforts do not have any specific implementation completion date, they are not included in Table 6-12 (DWR Table 6-6 Retail).

5 City of Turlock. Recycled Water. Accessed at
https://new.turlock.ca.us/watersewergarbageservice/waterconservation/recycledwater.asp on March 3, 2026. 2020 Projection for
2025 (MG) 2025 Actual Use (MG)
0 0
Check the box if recycled water was not used or distributed by the supplier in 2025, nor projected for use or distribution in 2020.

Proceed to the next table.

Total
Name of Receiving Supplier or Direct
Use by Wholesale Supplier

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-21 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

Table 6-12. Methods to Expand Future Recycled Water Use (DWR Table 6-6 Retail)

6.8 DESALINATED WATER
Desalination is the process of removing dissolved minerals from brackish water or saltwater to produce freshwater that can be used for municipal needs such as drinking water and industrial uses. It is one of several elements that may be included in a community’s water supply portfolio.

Turlock and SRWA’s service area is not located in a coastal area, so seawater desalination is not applicable and is not considered a technically or economically feasible opportunity to explore. Per CV2Sim groundwater modeling performed as part of the Turlock Subbasin GSP, the base of fresh water below the Cities of Turlock and Ceres is approximated to be 750 to 900 feet below msl.6 Due to the depth of saline water, along with other issues such as brine disposal, desalination of saline groundwater by Turlock is not feasible.

Therefore, Turlock and SRWA did not include or consider desalinated water in planning for its future supply sources.

6.9 FUTURE WATER PROJECTS

6.9.1 City of Turlock
As shown in Table 6 -13 (DWR Table 6 -7 Retail), Turlock has multiple groundwater projects planned to serve future growth. As part of Turlock’s 2025 WMP, Turlock developed a Capital Improvement Plan (CIP) that defines projects needed to serve existing and future water customers. While no water supply capacity projects were needed to serve existing customers, the CIP includes water supply projects needed to meet projected demands from future customers.

6 Source: WTSGSA/ETSGSA, Todd Groundwater. July 2024. Turlock Subbasin GSP. Figure 4 -9.

Name of Action Description Expected Increase in Recycled Water Use (MG)
Recycled water delivered to
Turlock Irrigation District For agricultural irrigation use 652 652
2,000
Total (MG)
DWR NOTES:

Units of measure (AF, CCF, MG) MUST remain consistent with units reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

The unit conversion to Acre Feet addresses the Water Code's requirement that this value be provided in acre-feet.

NOTES: (a) As part of SRWA’s Water Sales Agreement with TID, Turlock planned to begin providing 2,000 acre-feet per year (652 MGY) of recycled water to TID for agricultural irrigation in 2022. However, recycled water deliveries to TID have not yet commenced. For the purposes of this plan, it is assumed that recycled water deliveries from Turlock to TID will begin by approximately 2028.

Check the box if the Supplier does not plan to expand recycled water use in the future. Supplier will not complete the table below but will provide narrative explanation.

Provide page location of narrative in the UWMP
Unit Conversion to AF
Planned Implementation
Year
2028. See note (a).

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-22 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

The water supply projects defined in the CIP include constructing two new groundwater wells with treatment by 2028, and four additional groundwater wells with treatment by 2038. Actual implementation timing may vary depending on the timing of development within Turlock. The expected increase in available supply shown in Table 6 -13 (DWR Table 6-7 Retail) assumes that each well has a capacity of 1,500 gpm, consistent with the WMP.

Turlock’s CIP also include s the installation of arsenic treatment on two existing wells to maintain operability of these wells and improve supply reliability . As th e purpose of this treatment project is to maintain current supply capacity , compared to adding new capacity, this project is not included in Table 6-13 (DWR Table 6 -7 Retail) . Additional details about Turlock’s future water supply projects are described in the Turlock 2025 WMP.

Table 6-13. Expected Future Water Supply Projects or Programs (DWR Table 6-7 Retail)

6.9.2 SRWA
SRWA’s future water supply projects through 2050 are shown in Table 6-14 (DWR Table 6-7 Wholesale) and include a filter capacity study that is currently underway and a potential future expansion of the SRWA WTP.

SRWA’s filter capacity study is evaluating whether higher filter loading rates are feasible for the four existing granular media filters at the SRWA WTP . The filter capacity testing is planned to be completed in 2027, with the increase in WTP capacity expected to be available starting in 2028. Based on preliminary estimates, the study could potentially lead to a re-rating of the filter loading rate from 6 GPM/SF to 8 GPM/SF. This loading rate increase could increase the overall WTP capacity by up to 4.9 MGD, or from 15 MGD to 19.9 MGD. The actual increase in WTP capacity is dependent on the findings of the study and whether the filters operated at these higher filtration rates comply with the regulatory performance requirements from the State Water Board’s Division of Drinking Water (DDW).

Drop Down
List
(yes/no)
If Yes,
Supplier
Name
Construct Two New Wells (5 and 16)
with Treatment (PWW-2 and PWW-3) No Potable 2028 All Year Types 1,570 Construct Four New Wells with
Treatment (PWW-4 to PWW-7) No Potable 2038 All Year Types 3,139 Planned for Use
in Year Type
Drop Down List
NOTES: Future water supply projects are defined in Turlock's 2025 Water Master Plan.

DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure reported in Submittal Table 2-3.

Check the box if some or all of the supplier's future water supply projects or programs are not compatible with this table and are described in a narrative format.

Check the box if there are no expected future water supply projects or programs that provide a quantifiable increase to the agency's water supply.

Proceed to the next table.

Planned
Implementation
Year
Joint Project with
other suppliers? Expected
Increase in
Water Supply
to Supplier
(This may be
a range) (MG)
Provide page location of narrative in the UWMP
Name of Future Projects or Programs
Additional
Description
(as needed)
Potable or
Non-Potable
(after treatment
if treated)
(OPTIONAL)
Drop Down list

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-23 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

SRWA is also considering a future expansion of the WTP, referred to as the “Phase 2 expansion”, to meet future water demands from existing SRWA customers (i.e., Cities of Turlock and Ceres) and future customers. The current capacity of the WTP is 15 MGD but may be expanded to increase capacity to 30 MGD with the Phase 2 expansion. Based on the water demand projections for the Cities of Turlock and Ceres from their respective 2025 WMPs, both Cities anticipate the need for the Phase 2 expansion to 30 MGD within the planning horizon of this Joint UWMP to meet future water demands.

Based on the findings of the Cities’ 2025 WMPs, the Phase 2 expansion to 30 MGD is tentatively planned between 2041 to 2045 but is subject to change depend ing on the timing of development in Ceres and Turlock, as well as the possibility of other future water customers. Future buildout of the WTP would be 45 MGD but is not expected during the planning horizon of this Joint UWMP. This anticipated schedule differs from SRWA’s 2020 UWMP, which had projected buildout of the WTP to 45 MGD by 2035. The timing and phasing of the WTP expansion has been updated in this Joint UWMP to reflect the slower growth patterns identified in the Cities’ WMPs compared to growth projections in past planning efforts.

SRWA has incorporated provisions into the initial WTP site layout for future expansion of the WTP. Areas of the WTP site have been reserved for future treatment trains.

Table 6-14. Expected Future Water Supply Projects or Programs (DWR Table 6-7 Wholesale)

Drop Down
List
(yes/no)
If Yes,
Supplier Name
SRWA WTP Filter
Capacity Study Yes
Cities of
Turlock and
Ceres
Filtration capacity
study for existing
filters to expand
WTP capacity from
15 MGD to 19.9
MGD.

See note (a).

Potable 2028 All Year Types 1,789
SRWA WTP Phase 2
Expansion Yes
Cities of
Turlock and
Ceres
Expanding WTP
capacity from 19.9
MGD to 30 MGD.

See note (b).

Potable 2041 to 2045 All Year Types 2,513
Name of Future
Projects or Programs
Additional
Description
(as needed)
Potable or Non-
Potable
(after treatment if
treated)
(OPTIONAL)
Drop down list
Planned
Implementation
Year
Planned for Use in
Year Type
Drop Down list
Expected Increase
in Water Supply to
Supplier
(This may be a
range) (MG)
Joint Project with other
suppliers?
Provide page location of narrative in the UWMP
Check the box if some or all of the supplier's future water supply projects or programs are not compatible with this table and are described in a narrative format.

Check the box if there are no expected future water supply projects or programs that provide a quantifiable increase to the agency's water supply.

Proceed to the next table.

DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure reported in Submittal Table 2-3.

NOTES: (a) Filter capacity study is anticipated to increase SRWA's WTP capacity by up to 4.9 mgd, to a total capacity of up to 19.9 MGD. (b) SRWA's WTP Phase 2 expansion is anticipated to increase capacity to 30 MGD. The planned implementation timing for the SRWA WTP expansion is approximate and will be determined closer to when additional supply capacity is needed. The expected increase in available supply is constrained by the maximum annual surface water agreement with TID (9,776 MG).

Chapter 6
Water Supply Characterization

N-C-693-20-16-01-WP-Task 20-2025 UWMP
6-24 SRWA and City of Turlock
Joint 2025 Urban Water Management Plan
May 2026

6.10 SUMMARY OF EXISTING AND PLANNED SOURCES OF WATER

6.10.1 City of Turlock
Turlock’s existing and planned sources of water can be summarized as follows:
• Turlock maintains 15 active, potable groundwater wells, in addition to 4 non-potable groundwater wells for landscape irrigation.
— To maintain adequate groundwater supply capacity to meet future demands, Turlock plans to develop six new potable groundwater wells and add treatment to two existing wells within the UWMP planning horizon.
• Turlock is currently contracted to purchase up to 10 MGD (up to 3,650 MGY) of treated surface water from SRWA, with plans for future expansion of surface water use as WTP capacity expansions increase the available surface water supply. — Turlock anticipates being able to purchase up to 13.3 MGD (up to 4,840 MGY) of treated surface water from SRWA starting in 2028 pending the results of SRWA’s on-going filter capacity study.
— Turlock anticipates being able to purchase up to 20 MGD (up to 7,300 MGY) of treated surface water from SRWA from SRWA’s planned Phase 2 expansion, which is projected to occur between 2041 and 2045.
• Turlock maintains a series of stormwater detention basins that contribute to groundwater recharge.
• Turlock currently provides recycled water for industrial use (TID Walnut Energy Center), landscape irrigation, and agricultural irrigation, and plans to continue these uses in the future.
• Turlock does not currently exchange or transfer water nor plans to exchange or transfer water with other water systems.
• Turlock neither currently uses nor plans to use desalinated water.

Turlock’s actual potable and non-potable water supplies used in 2025 are summarized in Table 6-15 (DWR Table 6-8 Retail). The volume shown is based on the actual 2025 production from each potable and non- potable source.

As shown in Table 6-15 (DWR Table 6-8 Retail), Turlock’s entitlement for purchased surface water is based on its current 10 MGD WTP allocation, equivalent to a maximum volume of 3,650 MGY. Turlock does not have a specified groundwater pumping limit for its potable and non-potable groundwater uses.

Chapter 6
Water Supply Characterization

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Joint 2025 Urban Water Management Plan
May 2026

Table 6-15. Water Supplies – Actual (DWR Table 6-8 Retail)

Turlock’s projected future potable and non -potable water supplies are summarized in Table 6 -16 (DWR Table 6-9 Retail). Projected annual potable water supplies are anticipated to increase to 17,682 MG in 2050, which exceeds the projected potable water demands for 2050 shown in Chapter 4.

Projected groundwater supplies were estimated based on the maximum annual groundwater pumping in the past five years as shown in Table 6-2 (DWR Table 6-1 Retail), plus the additional groundwater capacity from Turlock’s future water supply projects shown in Table 6 -13 (DWR Table 6 -7 Retail). The projected increase in surface water supplies available to Turlock incorporates SRWA’s on-going filter capacity study which is anticipated to result in additional capacity in 2028 and the Phase 2 WTP expans ion planned between 2041 to 2045. Refer to Table 6 -14 (DWR Table 6-7 Wholesale) for additional details on SRWA’s future water projects.

Water Supply
Drop down list
May use each category multiple
times. These are the only water
supply categories that will be
recognized by the WUEdata
online submittal tool
Potable or Non-
Potable
(after treatment if
treated)
(OPTIONAL)
Drop Down list
Actual Volume
(MG)
Total
Entitlement
(OPTIONAL)
See 'DWR Notes'
below (MG)
Groundwater (not
desalinated) Turlock's production wells Potable 4,042 N/A Purchased or Imported Water Treated surface water
purchased from SRWA Potable 2,104 3,650
Recycled Water Disinfected tertiary recycled
water Non-Potable 3,902 N/A
Groundwater (not
desalinated)
Non-potable raw water
irrigation wells at City parks Non-Potable 104 N/A
6,146 N/A
4,006 N/A
10,151 N/A
2025
NOTES: Total entitlement for the purchased water is based on Turlock's current 10 MGD allocation of the SRWA WTP.

DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

This table identifies the unit of measure selected in Submittal Table 2-3.

Total Entitlement: e.g. Water Right, Groundwater Allocation, Contracted Amount.

Total
Subtotal Potable
Subtotal Non-Potable
Additional Description
(as needed)

Chapter 6
Water Supply Characterization

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Joint 2025 Urban Water Management Plan
May 2026

Table 6-16. Water Supplies – Projected (DWR Table 6-9 Retail)

Water Supply
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Groundwater (not
desalinated)
Turlock's production wells.

See note (a). Potable 8,026 N/A 8,026 N/A 11,165 N/A 11,165 N/A 11,165 N/A Purchased or Imported
Water
Treated surface water
purchased from SRWA.

See note (b).

Potable 4,842 4,842 4,842 4,842 4,842 4,842 6,517 6,517 6,517 6,517 Recycled Water
Disinfected tertiary
recycled water.

See note (c).

Non-Potable 4,520 N/A 4,520 N/A 4,520 N/A 4,520 N/A 4,520 N/A Groundwater (not
desalinated)
Non-potable raw water
irrigation wells at City
parks
Non-Potable 104 N/A 104 N/A 104 N/A 104 N/A 104 N/A
12,868 N/A 12,868 N/A 16,007 N/A 17,682 N/A 17,682 N/A
4,624 N/A 4,624 N/A 4,624 N/A 4,624 N/A 4,624 N/A
17,492 N/A 17,492 N/A 20,631 N/A 22,306 N/A 22,306 N/A
Projected Water Supply (Report to the Extent Practicable) Drop down list
May use each category
multiple times. These are
the only water supply
categories that will be
recognized by the WUEdata
online submittal tool
Additional Detail on Water
Supply
Potable or Non-
Potable
(after treatment if
treated)
(OPTIONAL)
Drop Down list
2050 (opt)
Total
NOTES: (a) Turlock's projected volume of groundwater available is estimated to be the maximum annual groundwater volume pumped in the past five years plus additional capacity from Turlock's future groundwater supply projects identified in DWR Table 6-7R. These future projects include constructing six new wells with treatment by 2040. (b) Turlock's projected volume of purchased water available from SRWA in 2030, 2035, and 2040 assumes a 13.3 MGD allocation for Turlock, based on the WTP's re-rated capacity of 19.9 MGD. Phase 2 expansion of the SRWA WTP from 19.9 MGD to 30 MGD total capacity is assumed to occur in 2041. The Phase 2 expansion yields an allocation of 20 MGD to Turlock in 2045 and 2050; total volume available is limited by Turlock's two- thirds allocation of the maximum annual water supply available per the Water Sales Agreement (9,776 MG). Buildout expansion of the WTP to 45 MGD is not planned within this UWMP planning horizon. (c) Wastewater and recycled water flow projections through 2050 are not available. Volumes presented are based on projected recycled water demands. Actual recycled water supply availability may vary. 2030 2035 2040 2045
Subtotal Non-Potable
Subtotal Potable
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

Total Entitlement: e.g. Water Right, Groundwater Allocation, Contracted Amount.

Chapter 6
Water Supply Characterization

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Joint 2025 Urban Water Management Plan
May 2026

6.10.2 SRWA
SRWA’s existing water supply and entitlement is summarized in Table 6 -17 (DWR Table 6-8 Wholesale).

In 2025, SRWA produced 3,517 MG of treated surface water, which is less than its maximum annual water supply available based on its Agreement with TID (9,776 MG or 30,000 AFY).

Table 6-17. Water Supplies – Actual (DWR Table 6-8 Wholesale)

SRWA’ planned water supplies through 2050 is summarized in Table 6-18 (DWR Table 6-9 Wholesale). The projected surface water availability through 2050 incorporates SRWA’s on-going filter capacity study , which is anticipated to result in additional capacity in 2028, and the Phase 2 WTP expansion planned between 2041 to 2045. Refer to Table 6 -14 (DWR Table 6-7 Wholesale) for additional details on SRWA’s future water projects. The total entitlement shown through 2050 is 9,776 MG (30,000 AFY) based on SRWA’s Agreement with TID.

The reasonably available volume shown in Table 6 -18 (DWR Table 6 -9 Wholesale) is based on SRWA’s WTP capacity. The reasonably available volume for each five -year increment is based on the limiting factor of either:

WTP capacity during that five-year increment, or
Maximum annual water supply available based on the Agreement, equivalent to 9,776 MG (30,000 AFY).

Additionally, SRWA’s maximum annual water supply available was reduced by two percent (from 9,776 MG to 9,580 MG) to account for the average normal year water allocation by TID based on TID’s most recent 15 years of water allocations to its customers. Chapter 7 provides additional information on TID’s allocation history and classification of normal year water supplies.

Water Supply
Drop down list
May use each category multiple
times.These are the only water
supply categories that will be
recognized by the WUEdata
online submittal tool
Potable or Non-Potable
(after treatment if treated)
(OPTIONAL)
Drop Down list
Actual Volume
(MG)
Total Entitlement
(OPTIONAL)
See 'DWR Notes'
below (MG)
Surface water (not
desalinated)
Surface water diverted
from Tuolumne River per
long-term transfer with TID
Potable 3,517 9,776
3,517 9,776
0 0
3,517 9,776
NOTES: Total Entitlement is based on SRWA and TID's Water Sales Agreement, which allows SRWA to purchase up to 30,000 AFY (equivalent to 9,776 MG) of untreated Tuolumne River surface water. Actual use may be limited by SRWA's current WTP capacity of 15 MGD.
2025
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

Total Entitlement: e.g. Water Right, Groundwater Allocation, Contracted Amount.

Total
Subtotal Potable
Subtotal Non-Potable
Additional Description
(as needed)

Chapter 6
Water Supply Characterization

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May 2026

Table 6-18. Water Supplies – Projected (DWR Table 6-9 Wholesale)

Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Reasonably
Available
Volume (MG)
Total
Entitlement
(OPTIONAL)
See 'DWR
Notes' below
Surface water (not
desalinated)
Surface water diverted
from Tuolumne River per
long-term transfer with
TID
Potable 7,264 9,776 7,264 9,776 7,264 9,776 9,580 9,776 9,580 9,776 7,264 9,776 7,264 9,776 7,264 9,776 9,580 9,776 9,580 9,776 0 0 0 0 0 0 0 0 0 0
7,264 9,776 7,264 9,776 7,264 9,776 9,580 9,776 9,580 9,776Total NOTES: Reasonably available volume is based on the limiting factor of either 1) WTP capacity or 2) normal-year water allocation between SRWA and TID. Projected volume of surface water available in 2030 through 2040 is based on the WTP's capacity of 19.9 MGD, assuming that the filter re-rating study is completed in 2027. The Phase 2 WTP exansion from 19.9 MGD to 30 MGD total capacity is projected to occur between 2041 and 2045. In 2045 and 2050, reasonably available volume is limited by the normal-year water allocation between SRWA and TID, which is expected to be 98 percent of total volume requested. Refer to Chapter 7 for more information.

Subtotal Potable
Subtotal Non-Potable
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in a Submittal Table 2-3.

Total Entitlement: e.g. Water Right, Groundwater Allocation, Contracted Amount.

Water Supply Projected Water Supply (Report to the Extent Practicable) 2030 2035 2040 2045 2050 (opt)Drop down list
May use each category
multiple times.These are the
only water supply categories
that will be recognized by the
WUEdata online submittal
tool
Additional Detail on
Water Supply
Potable or Non-Potable
(after treatment if treated)
(OPTIONAL)
Drop Down list

Chapter 6
Water Supply Characterization

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Joint 2025 Urban Water Management Plan
May 2026

6.11 SPECIAL CONDITIONS
This section provides a discussion of climate change impacts and regulatory conditions that may affect the availability and reliability of Turlock and SRWA’s water supply sources.

6.11.1 Climate Change Impacts
Anticipated climate change impacts to Turlock and SRWA’s water supplies are discussed below. Additional details can be found from the referenced studies, which include:
• Turlock Irrigation District 2020 Agricultural Water Management Plan (AWMP). March 2021. • East Stanislaus Region Integrated Regional Water Management Plan Update. February 2018. • San Joaquin Valley Summary Report. California’s Fourth Climate Change Assessment.

September 2018.
• Sensitivity of Upper Tuolumne River Flow to Climate Change Scenarios. January 2012.

Hydrocomp, Inc., San Francisco Public Utilities Commission (SFPUC), and TID.

SRWA’s water supply is dependent on Tuolumne River flow conditions and TID’s ability to supply sufficient quantities of Tuolumne River water to its customers. Based on a review of the above studies, the anticipated climate change impacts on SRWA’s water supply are summarized below:
• Change in timing of runoff in the Tuolumne River, with less runoff occurring during peak water demand periods (spring-summer);
• Reduction in total runoff in the Tuolumne River;
• Reduced precipitation as snowfall and reduced snowpack in the Sierra Nevada Mountains; • More frequent and more severe droughts in the future leading to the possibility of more frequent curtailments of Tuolumne River water diversions and reduced surface water allocations by TID;
• Increased evaporation on Don Pedro Reservoir reducing TID’s available supply; • Increased average temperatures and evapotranspiration, which may increase SRWA’s wholesale and Turlock’s retail customer water demands (e.g., landscape irrigation); and • Increased demand and competition for Tuolumne River surface water by TID’s customers due to increased crop evapotranspiration and subsequent increase in irrigation water requirements.

Based on available historical data and projected future streamflow in the Tuolumne River 7, the amount of annual runoff in the Tuolumne River below La Grange Dam occurring during the spring -summer period (April through July) has decreased over the past century and will likely continue to decrease in the next century (TID 2020 AWMP). Conversely, increasingly more runoff has occurred during the fall-winter period, outside of the irrigation season (TID 2020 AWMP). California’s Fourth Climate Change

7Historical full natural flows along the Tuolumne River are reported by DWR’s California Cooperative Snow Surveys, available through the California Data Exchange Center. Projected changes to Tuolumne River flows are derived from a number of studies prepared by the United States Bureau of Reclamation (USBR), DWR, and TID.

Chapter 6
Water Supply Characterization

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Assessment for San Joaquin Valley and a 2012 SFPUC/TID joint study, Sensitivity of Upper Tuolumne River Flow to Climate Change Scenarios, suggest future trends of decreased Tuolumne River runoff flows over the next 100 years.

The shift in timing of Tuolumne River flows and projected reduction in total flows have the potential to impact TID’s future surface water allocations to SRWA. With reduction in Tuolumne River flows during the spring-summer period, TID will face challenges in its ability to meet peak customer water demands during dry years while ensuring that adequate in stream flow requirements are met per State and Federal requirements.

TID’s 2020 AWMP provides more information on climate change impacts and TID’s actions to address these impacts.

6.11.2 Regulatory Conditions
Regulatory conditions for Turlock and SRWA’s planned projects and emerging regulatory conditions that may impact water supplies are discussed below.

Filter Capacity Study. SRWA’s on-going filter capacity study is anticipated to increase the SRWA WTP capacity. This study will require coordination with DDW. Title 22 of the California Code of Regulations (CCR) specifies in Section 64660 that WTPs like SRWA’s WTP, with conventional filtration using dual media, must be operated at filtration rates not to exceed 6.0 GPM/SF. However, this section of the CCR contains a provision where higher filtration rates (above 6 GPM/SF) may be approved if the water supplier demonstrates to DDW that the filters operated at these higher filtration rates comply with the regulatory performance requirements.

WTP Phase 2 Expansion. The planned WTP Phase 2 Expansion to 30 MGD would occur on the existing WTP site, as the initial site layout was designed to accommodate future expansion. The planned WTP expansion is anticipated to require various permits including, but not limited to:
— State Water Board, DDW - Permit to Operate and compliance with CCR Title 22 regulations for public drinking water
— Central Valley Regional Water Quality Control Board - National Pollutant Discharge Elimination System General Construction Storm Water Permit — San Joaquin Valley Air Pollution Control District - Authority to Construct and compliance with air quality regulations
Bay-Delta Water Quality Control Plan. The State Water Board’s Bay-Delta Water Quality Control Plan (Bay-Delta Plan) presents emerging regulatory conditions that may impact SRWA’s available water supply from the Tuolumne River. State law requires that the State Water Board and the Regional Water Quality Control Boards adopt Water Quality Control Plans that include measures to protect water quality in the state’s streams, rivers, and lakes.

The Bay-Delta Plan identifies beneficial water uses to be protected in the Bay-Delta, including: municipal and industrial, agricultural and fish and wildlife, water quality and flow objectives to reasonably protect the beneficial uses. The Bay-Delta Plan includes an implementation program to meet its objectives. Under the program, the State Water Board may take actions, including imposing minimum flow requirements, or habitat restoration requirements for diverters.

Chapter 6
Water Supply Characterization

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As the Tuolumne River is a tributary to the San Joaquin River, the Bay-Delta Plan sets instream flow requirements and water quality objectives for the Tuolumne River. On December 12, 2018, the State Water Board adopted amendments to the Bay-Delta Plan which established Lower San Joaquin River (LSJR) flow objectives and revised southern Delta salinity objectives. These amendments to the Bay-Delta Plan applied to three tributaries to the San Joaquin River: the Tuolumne, Merced, and Stanislaus Rivers. The flow objectives for the Tuolumne would require TID and MID to release 40 percent of unimpaired flows into the Tuolumne River from February 1 to June 30 for salmon and salinity control in the Delta. Per TID’s 2020 AWMP, TID, MID, and SFPUC currently release approximately 17 percent of the unimpaired flows to the Tuolumne River, while the remainder is diverted for beneficial use.

The State Water Board released revised draft updates to the Bay-Delta Plan, including LSJR flow and southern Delta salinity provisions, in December 2025 along with an updated environmental analysis. Public review and hearings are being conducted in early 2026.8 The Tuolumne River Partners – MID, TID, and SFPUC – have proposed a comprehensive alternative to the unimpaired flow requirements in the Bay-Delta Plan. The alternative is presented in the proposed Tuolumne River Voluntary Agreement, referred to as the Agreements to Support Healthy Rivers & Landscapes. This agreement provides a foundation for comprehensively managing the Tuolumne River and for continued management of Chinook salmon and rainbow trout within the lower Tuolumne River. While the proposed Voluntary Agreement will still require TID to release more water to the Tuolumne River for ecosystem benefits, the agreement will offer TID more opportunity to mitigate water supply impacts on its customers while still comprehensively managing the Tuolumne River to the State Water Board’s standards. The proposed Tuolumne River Voluntary Agreement is currently being evaluated by the State Water Board.

Federal Energy Regulatory Commission (FERC) relicensing for TID and MID’s Don Pedro Reservoir. Concurrent with the development of the Tuolumne River Voluntary Agreement, FERC is relicensing Don Pedro Reservoir for TID and MID. FERC may amend flow requirements that could affect water supply to SRWA. FERC has the authority to license dams with power plants on navigable rivers. The Don Pedro Reservoir falls under the jurisdiction of FERC because of TID and MID’s 203-megawatt (MW) powerhouse. The original 50-year FERC license for Don Pedro Reservoir expired in April 2016. TID and MID are in the process of securing a new license with FERC to continue operating the Don Pedro Reservoir. Both TID and MID have been operating on a year-to-year renewal basis since 2016 until a long-term license is granted by FERC.

FERC has the authority to license and relicense non -federal hydropower project s for terms between 30 to 50 years. FERC license requirements for Don Pedro Reservoir include minimum instream flow release requirements that vary with the water year type. FERC is mandated to give equal consideration to beneficial public uses (including energy conservation, irrigation, flood control, water supply, recreational opportunities, and other aspects of environmental quality) and adequate protection, mitigation and enhancement of fish and wildlife.

8 State Water Resources Control Board. Sacramento/Delta Update to Bay-Delta Plan. Accessed at https://www.waterboards.ca.gov/waterrights/water_issues/programs/bay_delta/comp_review.html on March 3, 2026.

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Water Supply Characterization

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6.12 ENERGY INTENSITY
In accordance with California Water Code §10631.2(a), the energy intensity to provide water service to Turlock and SRWA’s water customers over a one-year period is presented in this section to the extent that the information is available. The amount of energy to pump, treat, and distribute Turlock and SRWA’s water supply within the systems they own and operate is included.

Water energy intensity is the total amount of energy in kilowatt hour s (kWh), calculated on a whole-system basis, expended on a per million gallon basis, to deliver water from Turlock and SRWA’s sources to its respective water customers. Understanding the whole -system energy intensity allow s Turlock and SRWA to make informed strategies in managing its water supplies and operating its system as follows:
• Identifying energy saving opportunities because energy consumption is often a large portion of the cost of delivering water
• Calculating energy savings and greenhouse gas emissions reductions associated with water conservation programs
• Identifying potential opportunities for receiving energy efficiency funding for water conservation programs
• Informing climate change mitigation strategies
• Benchmarking energy use at each water acquisition and delivery step and the ability to compare energy use among similar agencies

6.12.1 Water System Energy Intensity
In Table 6-19 (DWR Table O-1B), the energy intensity of Turlock’s water service is calculated as an annual utility total for 2025. Annual energy use quantities were obtained from Turlock’s monthly TID billing data for the following assets:
• All groundwater well sites with energy usage in 2025 (approximately 25 wells total including both active and inactive/offline wells), and including both pumping and treatment for well sites with wellhead treatment systems,
• Three booster pump stations at the Fulkerth, Kilroy, and D Street storage tanks (each with firm pumping capacity of 7.8 MGD),
• One booster pump station at the Terminal Reservoir, which receives SRWA surface water (with a firm pumping capacity of 12 MGD), and
• Other ancillary water system facilities with energy usage (e.g., remote telemetry units).

The total energy use for these facilities in 2025 was approximately 7,718,708 kWh. Based on Turlock’s total groundwater production in 2025 of 4,042 MG (which excludes purchased surface water from SRWA), the total energy intensity for Turlock’s water service area is approximately 1,910 kWh/MG. Turlock does not currently utilize any non-consequential hydropower.

Information on SRWA’s energy use associated with treating and delivering surface water to the Cities is provided in Table 6-20 (DWR Table O-1A).

Chapter 6
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Table 6-19. Energy Intensity for Turlock’s Retail Potable Deliveries – Water Supply Process Approach (DWR Table O-1B) Water Delivery Product
drop down list
(If delivering more than one type of product recommend
using Table O-1C)
Retail Potable
Deliveries
Start Date of Reporting Period 1/1/2025
End Date of Reporting Period 12/31/2025
Is upstream embedded energy in the values reported? No
Units of Measure for Water MG Total Utility
See DWR NOTES Hydropower Net Utility
4,042 - 4,042 7,718,708 - 7,718,708 1,910 1,910 Quantity of Self-Generated Renewable Energy
0 kWh
Data Quality (Estimate, Metered Data, Combination of Estimates and Metered Data) Metered Data
Data Quality Narrative:

Narrative:

Energy consumption is based on Turlock's monthly metered electric bills through Turlock Irrigation District (TID) during calendar year 2025. Energy usage includes energy consumed at all of Turlock's active groundwater well sites, which may also include some energy used by the wellhead treatment systems in place at some well sites and other remote telemetry units (RTUs). Energy usage also includes energy consumed at Turlock's four booster pump stations that pump out of Turlock's storage reservoirs, including the Terminal Reservoir. Volume of water entering process is based on Turlock's total potable groundwater volume pumped in 2025, consistent with DWR Table 6-1 Retail. Energy use shown does not include energy consumed at the SRWA WTP or for conveying surface water from the SRWA WTP to Turlock's Terminal Reservoir.

Only for Water Delivery Products Under the Urban Water Supplier's Operational Control
Sum of All Water
Management Processes Non-Consequential Hydropower
DWR NOTES:

Total Utility:The volume of water entered in the “Total Utility” column should equal the volume of water entering the distribution system (excluding recycled water); in most cases, this is the total volume calculated in UWMP Table 4-1: 2025 Actual Total Uses for Potable and Non-Potable Water. Note if recycled water is included in your Submittal Table 4-1, you must exclude it from your volume in this table.

Energy consumed includes energy used by City of Turlock for water storage, conveyance, treatment, and distribution of groundwater. Energy consumed and volume of water entering process is based only on groundwater and does not include purchased surface water from SRWA.

Volume of Water Entering Process
Energy Consumed (kWh)
Energy Intensity (kWh/vol. converted to MG)

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In Table 6-20 (DWR Table O-1A), the energy intensity of SRWA’s wholesale water service is calculated as an annual utility total for 2025. Annual energy use quantities were obtained from SRWA’s monthly TID billing data for the following assets:
• Raw water pump station, listed under the “Extract and Divert” column • SRWA WTP treatment processes, listed under the “Treatment” column • Finished water pump stations, listed under the “Conveyance” column The total energy use for these facilities in 2025 was approximately 4,373,063 kWh. Based on SRWA’s total surface water production in 2025 of 3,517 MG, the total energy intensity for SRWA’s water service is approximately 1,243 kWh/MG. SRWA does not currently utilize any non-consequential hydropower.

Chapter 6
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Table 6-20. Energy Intensity for SRWA’s Wholesale Potable Deliveries – Water Supply Process Approach (DWR Table O-1A)

Wholesale
Potable
Deliveries
1/1/2025
12/31/2025
No
Units for
Water
Volume
Extract and
Divert
Place into
Storage Conveyance Treatment Distribution
Total Utility
See DWR
NOTES
Hydropower Net Utility
MG 3,517 - 3,517 3,517 - 3,517 - 3,517
N/A 1,613,600 - 2,037,863 721,600 - 4,373,063 - N/A
N/A 459 0 579 205 0 1,243 0 0
Quantity of Self-Generated Renewable Energy
0 kWh
Data Quality (Estimate, Metered Data, Combination of Estimates and Metered Data) Metered Data
Data Quality Narrative:

Narrative:

SRWA's WTP includes a raw water pump station that extracts raw water from the Tuolumne River via an infiltration gallery. Raw water is then treated, and then pumped via finished water pump stations to the Cities of Turlock and Ceres' terminal reservoirs.

Volume of Water Entering Process
Energy Consumed (kWh)
Energy Intensity (kWh/vol. converted to MG)
DWR NOTES: Total Utility:The volume of water entered in the “Total Utility” column should equal the volume of water entering the distribution system (excluding recycled water); in most cases, this is the total volume calculated in UWMP Table 4-1: 2025 Actual Total Uses for Potable and Non-Potable Water. Note if recycled water is included in your Submittal Table 4- 1, you must exclude it from your volume in this table.

Energy consumption is based on monthly metered electric bills through Turlock Irrigation District (TID) during calendar year 2025. Values are based on energy consumed at SRWA's WTP, including the raw water pump station (shown in the "Extract and Divert" column), treatment system (shown in the "Treatment" column), and finished water pump station (shown in the "Conveyance" column). Volume of water entering process is based on SRWA's total water sales to the Cities of Turlock and Ceres, consistent with DWR Table 4-1 Wholesale.

Water Delivery Product
drop down list
(If delivering more than one type of
product recommend using Table O-1C)
Only for Water Delivery Products Under the Urban Water Supplier's Operational Control Start Date of Reporting Period
Water Management Process
Non-Consequential
Hydropower
(if applicable)
End Date of Reporting Period
Is upstream embedded energy
included in the values reported?

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6.12.2 Wastewater System Energy Intensity
As discussed in Section 6.7, Turlock provides wastewater collection, treatment, and disposal services to customers within its city limits as well as Keyes CSD, Denair CSD, and up to 2 MGD of primary treated wastewater from the City of Ceres. Turlock owns and operates the wastewater collection, treatment, and disposal system.

The energy intensity associated with Turlock’s wastewater services for 202 5 is provided in Table 6-21 (DWR Table O -2). Wastewater collection and conveyance has an energy intensity of 118 kWh/MG, the treatment process has an energy intensity of 4,158 kWh/MG, and discharge and distribution of treated effluent have an energy intensity of 125 kWh/MG.

Table 6-21. Energy Intensity – Wastewater & Recycled Water (DWR Table O-2)

Start Date of Reporting Period 1/1/2025
End Date of Reporting Period 12/31/2025
Is upstream embedded energy in the values reported? No
Units of Measure for Water MG Collection /
Conveyance Treatment Discharge /
Distribution Total
3,902 3,902 3,902 11,706
461,525 16,224,257 486,823 17,172,605
118 4,158 125 1,467
- - - -
- - - -
- - - -
Quantity of Self-Generated Renewable Energy related to
recycled water and wastewater operations
0 kWh
Data Quality (drop down)
Metered Data
Data Quality Narrative:

Narrative:

Volume of Wastewater Entering Process (volume units selected above) Wastewater Energy Consumed (kWh)
Volume of Recycled Water Entering Process (volume units selected above) Recycled Water Energy Consumed (kWh)
Wastewater Energy Intensity (kWh/volume converted to MG) Recycled Water Energy Intensity (kWh/volume converted to MG) Only for Water Delivery Products Under the Urban Water
Supplier's Operational Control
Water Management Process
Energy consumption is based on metered Turlock Irrigation District (TID) billing records for wastewater collection (i.e., sanitary sewer lift stations), treatment facilities, and discharge facilities for Calendar Year 2025. Wastewater volumes are based on metered effluent flow records.

Turlock's wastewater collection/conveyance involves the use of sanitary sewer lift stations, which convey wastewater to Turlock's Regional Water Quality Control Facility (RWQCF). After treatment at the RWQCF, treated effluent is discharged, with most effluent pumped to the Delta-Mendota Canal as part of the North Valley Program, and a smaller amount of effluent used as recycled water within Turlock's water service area.

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CHAPTER 7
Water Service Reliability and Drought Risk Assessment
This chapter describes Turlock and SRWA’s water service reliability under various hydrologic conditions through 2050. In assessing Turlock and SRWA’s water service reliability, a comparison of projected water supplies and demand under normal year, single dry year, and five-consecutive-year drought conditions is provided. This chapter includes Turlock and SRWA’s DRA which evaluates the risk of a severe drought occurring for the next five consecutive years. Findings show that Turlock’s water supplies are sufficient to meet the existing and projected water demands during normal and drought conditions, and that SRWA’s wholesale customers (Cities of Turlock and Ceres) sha ll maintain adequate groundwater supply capacity to meet demands during drought conditions when SRWA’s supplies are reduced.

Turlock and SRWA’s current and proposed water management tools to address the reliability of water supplies are also discussed in this chapter . Responses to water shortage conditions are addressed in Chapter 8 and Appendix G.

Where applicable, this chapter includes subsections to separately address the constraints and reliability of the groundwater, surface water, and recycled water supplies. The water service reliability assessment and DRA are also presented separately for Turlock’s retail customers and for SRWA’s wholesale customers.

7.1 CONSTRAINTS ON WATER SOURCES
This section presents the constraints on Turlock and SRWA’s water supplies for use in the following water service reliability assessment and DRA. This section includes discussion on Turlock’s groundwater and recycled water supply constraints, and SRWA’s surface water supply constraints. Information on groundwater supply constraints is primarily from Turlock’s 2020 UWMP, the 2024 Turlock Subbasin GSP, and Turlock’s 2024 Water Quality Report. Information on SRWA’s surface water supply constraints is primarily from SRWA’s 2020 UWMP, adopted in 2024.

7.1.1 Groundwater
As described in Chapter 6 , Turlock pumps groundwater from the underlying Turlock Subbasin for both potable and non-potable uses. Although Turlock is now less reliant on groundwater due to its new surface water supply, groundwater still represents a significant portion of the City’s water supply portfolio.

The Turlock Subbasin is not adjudicated and does not have pumping restrictions or allocations for Turlock or other urban groundwater users within the Subbasin. While Turlock does not face groundwater quantity limitations, its use of groundwater can be affected by water quality concerns and the high costs associated with treatment. As a result, Turlock closely monitors groundwater quality trends and emerging water quality regulations that could influence future groundwater use.

Turlock’s 2016 Hydrogeologic and Water Quality Assessment Report identified several groundwater constituents of concern within the Subbasin. Contaminants present in the area include salinity, arsenic, hexavalent chromium, nitrates, fuel, solvents, and synthetic organic compounds. Of the se, the constituents with the greatest potential for future impacts (i.e. salinity, arsenic, nitrates , 1,2,3-trichloropropane, and hexavalent chromium) are discussed in more detail below.

Turlock continuously monitors water quality in its water distribution system to ensure that it provides the necessary treatment to meet the State’s drinking water standards and delivers high-quality drinking water supply to its customers.

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7.1.1.1 Salinity
Salinity has been identified as a constituent of concern in the Turlock Subbasin in several studies including the Turlock Subbasin GSP . Salts can enter groundwater naturally or from human activities . Division of Drinking Water’s (DDW’s) secondary MCL for salinity includes a recommended limit of 500 milligrams per liter (mg/L), upper limit of 1,000 mg/L , and short-term limit of 1,500 mg/L, measured in total dissolved solids (TDS). In Turlock’s 2024 Annual Water Quality Report, the City indicated an average groundwater TDS concentration of 249 mg/L, with a maximum value of 334 mg/L, which is below the recommended MCL of 500 mg/L . Similarly, the Turlock Subbasin GSP finds that TDS concentrations are typically below 500 mg/L in the Western Upper and Wester Lower Principal Aquifer, which Turlock’s wells draw upon.1 Several other water suppliers in the area are members of the Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) program, with the stated objective to organize, facilitate and fund efforts needed for the efficient management of sali nity in the Central Valley. Although Turlock is not currently a member of CV-SALTS, the City does participate through its membership with the Central Valley Clean Water Association. Turlock will continue to monitor salinity levels in its groundwater supplies and act accordingly.

7.1.1.2 Arsenic
Arsenic has been identified as a constituent of concern in the Turlock Subbasin in several studies including the Turlock Subbasin GSP . Arsenic is naturally occurring in the Turlock Subbasin aquifer materials and leaches into the Subbasin’s groundwater. Turlock has taken several wells out of service due to arsenic concentrations approaching or exceeding the MCL of 10 micrograms per liter ( µg/L). Wells with slightly elevated arsenic concentrations are taken out of service but can operate under maximum day demand conditions or emergency conditions.2 In Turlock’s 2024 Annual Water Quality Report, the City reported an average arsenic concentration of 8.3 µg/L in its groundwater supply.

As shown in Turlock’s 2025 WMP, the City plans to install arsenic treatment for two wells (Wells 34 and 36) within the next few years . Turlock continues to regularly monitor arsenic contamination in its groundwater supplies and will continue to install treatment or make operational adjustments as needed.

7.1.1.3 Nitrates
Nitrates have been ident ified as a constituent of concern in the Turlock Sub basin in several studies including the Turlock Subbasin GSP. While nitrate in irrigation water is not a major concern for most crops, high concentrations of nitrate is a human health concern for potable water supplies.

The MCL for nitrate (as Nitrogen, N) in drinking water is 10 mg/L. In Turlock’s 2024 Annual Water Quality Report, the City reported an average nitrate concentration of 6.0 mg/L, with a maximum concentration of 9.9 mg/L in the City’s active wells. While these values are below the MCL and indicate that technically nitrate concentrations are within a safe range , some nitrate concentrations in the City’s wells are very close to the MCL . In fact, Turlock has closed several wells over the past decade due to nitrate levels exceeding the MCL. Turlock continues to regularly monitor nitrate contamination in its groundwater supplies to ensure that nitrate levels remain below the MCL. Wells that have concentrations exceeding

1 West Turlock Subbasin GSA and East Turlock Subbasin GSA. July 2024. Turlock Subbasin GSP. Section 4.3.5.3.2. 2 City of Turlock. March 2025. Water Master Plan.

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the MCL will be taken offline or be used only for blending with other groundwater supplies to maintain compliance with the MCL for nitrate.

7.1.1.4 1,2,3-Trichloropropane
1,2,3-TCP has been ident ified as a constituent of concern in the Turlock Sub basin in several studies including the Turlock Subbasin GSP. The State Water Board established an MCL and monitoring frequencies for 1,2,3-TCP which went into effect in January 2018. The MCL for 1,2,3-TCP is 0.005 µg/L and is based on a running annual average. In Turlock’s 2024 Annual Water Quality Report, the City reported a running annual average 1,2,3-TCP concentration of 0.003 µg/L in the City’s active wells, below the MCL of

0.005 µg/L.

Turlock will continue to monitor its wells for 1,2,3-TCP levels. Concurrent with regular monitoring, Turlock is in the process of addressing the elevated 1,2,3-TCP concentrations identified in certain impacted wells.

Turlock completed a comprehensive report evaluating 1,2,3-TCP for the City’s 16 active groundwater wells in November 2024 and has plans to install 1,2,3-TCP treatment for Well 36.3

7.1.1.5 Hexavalent Chromium
Hexavalent chromium, while not described in the Turlock Subbasin GSP as a major constituent of concern, was evaluated in Turlock’s 2016 Hydrogeologic and Water Quality Assessment Report and is monitored by the City. This constituent is addressed here due to California’s recent establishment of a drinking water MCL for hexavalent chromium.

Hexavalent chromium is a heavy metal that has been used in industrial applications and is also found naturally occurring throughout the environment. The State Water Board recently established the hexavalent chromium MCL value of 10 µg/L, which was made effective on October 1, 2024. In Turlock’s 2024 Annual Water Quality Report, the City reported an average hexavalent chromium value of 4.9 µg/L, with a maximum level of 6.8 µg/L, which is below the MCL of 10 µg/L.

7.1.2 Surface Water
As described in Chapter 6, SRWA receives Tuolumne River surface water via an Agreement with TID. The quality of water from the Tuolumne River is generally not of concern as SRWA treats the surface water at its WTP to a level consistently exceeding drinking water standards. Therefore, SRWA’s water s ervice reliability is mostly dependent on water quantity rather than water quality. The following is a general discussion regarding the constraints on SRWA’s water supplies.

The biggest factor in the availability of SRWA’s water supplies is climatic variability and associated constraints imposed on TID’s water availability on the Tuolumne River. Below average snowpack and/or prolonged periods of dry weather contribute to reduced water allocations from TID to SRWA. In addition, the provisions of the Agreement limit SRWA’s request such that the total amount of water requested for any year may not vary by more than 10 percent from the immediately prior year and the next succeeding year, unless approved by TID.

In accordance with the Agreement, SRWA submits a two -year water delivery schedule annually. The TID Board of Directors determines annual allocations to its customers based on various factors such as

3 March 2025. City of Turlock, Carollo. Water Master Plan. Table 5.1

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projected runoff, including the possibility of the occurrence of consecutive dry years, carryover storage projections in Don Pedro Reservoir, and in stream flow requirements for the Tuolumne River. TID’s determination of available water is typically announced in February or March for each year. Potential constraints to SRWA’s water supply allocation are discussed in the following subsections.

7.1.2.1 Federal Energy Regulatory Commission Fish Flow Requirement As described in Chapter 6, TID’s Don Pedro Reservoir FERC license requires minimum instream flow requirements to maintain healthy conditions for aquatic and riparian species in the Tuolumne R iver.

SRWA’s delivery schedule may not reduce flows in the Tuolumne River to less than the required minimum instream flows. TID is currently undergoing relicensing of the Don Pedro Reservoir with FERC – the results of which could alter minimum instream flow requirements.

7.1.2.2 Tuolumne River Emergency Curtailment Orders
In dry years, the State Water Board may curtail Tuolumne River water diversions. In the recent 2022 dry year, the State Water Board issued emergency curtailment order s affecting Tuolumne River diversions, including certain post -1914 appropriative water rights held by TID, a senior water right holder on the river. These curtailment orders temporarily restricted TID from diverting Tuolumne River flows under its post-1914 appropriative rights for direct use or for storage into Don Pedro Reservoir .

During these conditions, TID was still able to use surface water previously stored in Don Pedro Reservoir.

In response to the drought, TID’s water allocations during that year and the following year were reduced to manage stored carry over water supply in Don Pedro Reservoir for potential future dry years. Based on TID’s allocations to its customers during these previous curtailment orders, SRWA assumes that at least some surface water from TID will remain available during future curtailment periods .

7.1.2.3 Bay-Delta Plan
As described in Chapter 6, the State Water Board’s Bay-Delta Plan may further impact available water for Tuolumne River water right holders. The Bay -Delta Plan’s 2018 amendments proposed unimpeded flow requirements and salinity requirements for the LSJR and its three salmon -bearing tributaties, including the Tuolumne River. The State Water Board released revised draft updates to the Bay-Delta Plan, including LSJR flow and southern Delta salinity provisions, in December 2025 along with an updated environmental analysis. Public review and hearings for the proposed Bay-Delta Plan amendments are being conducted in early 2026.

As documented in TID’s 2020 A gricultural Water Management Plan (AWMP) , t he Bay -Delta Plan ’s proposed unimpeded flow requirements would significantly impact TID’s available surface water supplies.

Table 7-1 shows TID’s estimates of the Bay-Delta Plan’s impacts on TID’s available water for 2013 -2015, at the peak of the 2012 -2016 drought, if the Bay -Delta Plan had been in effect at that time (TID 2020 AWMP). Based on TID’s analysis, the available water allocation would have been significantly reduced in 2013 and reduced to zero for 2014 and 2015. The propo sed Tuolumne River Voluntary Agreement, as discussed in Chapter 6, may reduce diversion restrictions to Tuolumne River water right holders while still meeting the State Water Board’s goals for the Bay-Delta. The proposed Tuolumne River Voluntary Agreement is currently being evaluated by the State Water Board.

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Table 7-1 Estimate of Available TID Water Allocation in 2013-2015 Under the Bay-Delta Plan Year
Actual Available Water,
inches/acre
Theoretical Available Water
Under the Bay-Delta Plan,
inches/acre
2013 34 16
2014 20 0
2015 18 0
Source: Turlock Irrigation District. March 2021. Turlock Irrigation District 2020 Agricultural Water Management Plan (AWMP). Table 5.5.

Available Water in 2013-2015, Actual versus Theoretical Under the Bay-Delta Plan.

7.1.3 Recycled Water
As described in Chapter 6, Turlock uses a small amount of recycled water within its service area for landscape irrigation and industrial uses and exports the majority of its recycled water outside of its service area for agricultural irrigation. No legal, environmental, or water quality constraints are anticipated to impact recycled water use.

7.2 WATER SERVICE RELIABILITY ASSESSMENT
This section evaluates Turlock and SRWA’s water service reliability for a normal year, single dry year, and five-consecutive-year drought. Turlock and SRWA’s water service reliability are presented in five -year increments through 2050 based on the previous analysis of water use and supply (discussed in Chapter 4 and Chapter 6, respectively). For the purposes of this water service reliability assessment, available water supply during normal year, single dry year, and five -consecutive-year drought are compare d with unconstrained normal year customer demands.

During water shortage events identified here, Turlock and SRWA may implement their respective WSCPs.

Turlock and SRWA’s WSCPs are discussed in Chapter 8 and provided in Appendix G of this plan.

7.2.1 Year Type Characterization
This section describes the historical basis for projecting available supplies under various hydrologic conditions for use in the water service reliability assessment. Water supplies can vary year to year depending on hydrologic conditions. Historical data was used to develop a projected yield under three conditions: (1) normal year, (2) single dry year, and (3) five-consecutive-year drought. In accordance with the DWR Guidebook, each condition is defined as follows:
• Normal Year: The year or averaged range of years in the historical sequence most closely representing average water supply in years when no regional or state-wide drought declaration are in effect.
• Single Dry Year: The year with the lowest water supply in the historical sequence. • Five-Consecutive-Year Drought: The driest five-year historical sequence.

The following sections describe how Turlock’s groundwater supplies and SRWA’s surface water supplies vary under different water year types.

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7.2.1.1 Groundwater
Historically, Turlock has maintained reliable access to groundwater from the Turlock Subbasin during all water year types. As the Turlock Subbasin is not adjudicated and there are no t any pumping restrictions or allocations imposed on Turlock or other urban groundwater users within the Subbasin, Turlock’s groundwater supply is not expected to be reduced during single dry years or five-consecutive-year droughts.

As shown in Table 7-2 (DWR Table 7-1 Retail), quantification of retail supplies is not compatible with this table, as Turlock’s retail water supplies consist of both local groundwater (which does not have restrictions during drought years) and purchased surface water from SRWA. The basis of water year data for SRWA’s surface water is provided in Table 7-5 (DWR Table 7-1 Wholesale).

Table 7-2. Basis of Water Year Data (Reliability Assessment) (DWR Table 7-1 Retail)

7.2.1.2 Surface Water
In assessing normal year, single dry year, and five-consecutive-year drought conditions, SRWA’s available surface water supply may be constrained by:

SRWA’s WTP maximum capacity (currently 15 MGD),
TID’s available water allocations, and
The Agreement’s provision limiting variance of annual water supply request by no more than 10 percent from the prior year.

Historical allocations to TID’s customers from 2010 through 202 5 were used to project SRWA’s surface water supply under the three hydrologic conditions . Reviewing TID customer allocations is appropriate since the Agreement specifies that SRWA’s water allocation will be reduced in an equivalent manner as all other TID customers.

Table 7-3 shows TID’s historical allocations to its customers in inches per acre, and the percentage of full allocation. A full allocation for TID’s agricultural customers is defined as 48 inches per acre. The years italicized in Table 7-3 represent years in which the State of California declared emergency drought orders, which include 2012 through 2016, and 2021 through 2022.

% of Average Supply
Year Type
Base Year
If not using a calendar year,
type in the last year of the
fiscal, water year, or range
of years, for example, water
year 2024-2025, use 2025
Available Supplies if
Year Type Repeats
Check the box if quantification of available supplies
is not compatible with this table and is provided
elsewhere in the UWMP.

Location: Section 7.2.1.2, Table 7-5 (DWR Table 7-1
Wholesale)
Volume Available (MG)
Quantification of available supplies is provided in this table as either volume only, percent only, or both.

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Table 7-3. Historical TID Water Allocations
Year
Water Available to TID Customers,
inches/acre Percent of Full Allocation
2010 48 100
2011 48 100
2012(a) 30 63
2013(a) 34 71
2014(a) 20 42
2015(a) 18 38
2016(a) 36 75
2017 48 100
2018 48 100
2019 48 100
2020 42 88
2021(a) 34 71
2022(a) 27 56
2023 48 100
2024 48 100
2025 48 100
Normal Year-Average(b) 47 98%
Sources:

Turlock Irrigation District. March 2021. 2020 Agricultural Water Management Plan. (For 2015-2019) Turlock Irrigation District. November 2015. 2015 Agricultural Water Management Plan. (For 2010-2014) Turlock Irrigation District Board Meeting Minutes (2020-2025).

(a) Drought years, when State of California declared emergency drought orders. Includes years 2012-2016 and 2021-2022. (b) The normal year average is based on historical water allocations during recent non-drought years. Normal year average is rounded down to the nearest inches/acre.

Figure 7-1 shows TID’s historical allocations from 2010 through 2025 as a percentage of full allocation, as well as a year type characterization of hydrologic conditions. For the purposes of the water service reliability assessment, the normal year is assumed to be the average of historical water allocations during recent non-drought years (i.e., excluding 2012 -2016 and 2021 -2022). Therefore, during a normal year, SRWA expects to receive approximately 98 percent of the ir full allocation. The single dry year was assumed to be represented by the Year 2015, which had the lowest allocation. The five-consecutive-year drought is represented by the Years 2012 through 2016.

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Figure 7-1 Year Type Characterization Based on Historical TID Water Allocations Table 7 -4 presents SRWA’s estimated maximum surface water supply under the three hydrologic conditions, based on the representative years defined above. The table shows the maximum volume of surface water available if the hydrology from that type of year were to be repeated, along with the corresponding percentage of full allocation . Full allocation is defined in this table as 9,776 MG per year (30,000 AFY), which represents the maximum volume that SRWA can request from TID per the Agreement.

Table 7-4 Percent of Full Allocation for Hydrologic Conditions – SRWA Wholesale Surface Water Year Type Base Year
Maximum Volume
Available(a), MG
Percent of Full
Allocation(a)
Normal Year (Average) Average of Non-Drought
Years (2010-2025) 9,580 98
Single Dry Year 2015 3,666 38
Consecutive Dry Years - 1st Year 2012 6,110 63
Consecutive Dry Years - 2nd Year 2013 6,924 71
Consecutive Dry Years - 3rd Year 2014 4,073 42
Consecutive Dry Years - 4th Year 2015 3,666 38
Consecutive Dry Years - 5th Year 2016 7,332 75
(a) Maximum volume available is based on SRWA’s full allocation of 9,776 MG/year, or 30,000 AFY, based on the Agreement between SRWA and TID.

MG = million gallons

0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 TID Historical Allocation,
Percent of Full Allocation
Year
Five-Consecutive-Year Drought
(2012-2016)
Single Dry Year
(2015)
Normal Year (Average)

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Table 7 -5 (DWR Table 7 -1 Wholesale) estimates SRWA’s maximum available supply during the three hydrologic conditions and years described above. The table specifies the volume available and percentage of average supply available if the hydrology from that type of year were to repeat. Available volume shown is consistent with Table 7-3.

SRWA may consider purchasing supplemental surface water from other TID customers or from senior Tuolumne River water right holders, if available, during significant droughts. However, to be conservative in this analysis, supplemental surface water purchases are assumed not to be available and are not included in Table 7-4 and Table 7-5 (DWR Table 7-1 Wholesale).

Table 7-5. Basis of Water Year Data (Reliability Assessment) (DWR Table 7-1 Wholesale)

% of Average Supply
Average Year 2010-2025 100%
Single-Dry Year 2015 38%
Consecutive Dry Years 1st Year 2012 64%
Consecutive Dry Years 2nd Year 2013 72%
Consecutive Dry Years 3rd Year 2014 43%
Consecutive Dry Years 4th Year 2015 38%
Consecutive Dry Years 5th Year 2016 77%
Available Supplies if
Year Type Repeats
Check the box if quantification of available supplies
is not compatible with this table and is provided
elsewhere in the UWMP.

Location: [insert location from UWMP]
Volume Available (MG)
NOTES: Actual surface water volume currently available is lower based on SRWA’s current water treatment plant capacity (i.e. 5,475 MG). By 2028, the treatment plant capacity is expected to increase to 7,264 MG following the filter re-rating study and the capacity is expected to increase to 9,580 MG by 2045 following the Phase 2 expansion as discussed in Chapter 6 and shown in Table 6-18 (DWR Table 6-9 Wholesale).

DWR NOTES: Supplier may use multiple versions of Submittal Table 7-1 W if different water sources have different base years and the supplier chooses to report the base years for each water source separately. If a Supplier uses multiple versions of Submittal Table 7-1 W, in the "Note" section of each submittal table, state that multiple versions of Submittal Table 7-1 W are being used and identify the particular water source that is being reported in each submittal table.

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table reports the unit of measure selected in Submittal Table 2-3. 4,073
Quantification of available supplies is provided in this table as either volume only, percent only, or both.
6,924
3,666
7,332
9,580
3,666
6,110
Year Type
Base Year
If not using a
calendar year, type
in the last year of
the fiscal, water
year, or range of
years, for example,
water year 2024-
2025, use 2025

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7.2.2 Water Service Reliability – Normal Year

7.2.2.1 City of Turlock
Table 7-6 (DWR Table 7 -2 Retail [Potable]) compares Turlock’s available potable supply and demand during a normal year from 2030 to 2050. Turlock’s total potable supply available during a normal year is projected to be approximately 12,868 MG in 2030 and up to 17,682 MG in 2050. The increase in supply is due to Turlock’s planned groundwater well and treatment projects planned for 2028 and 2038, as well as the planned SRWA WTP filter capacity study in 2028 and WTP Phase 2 Expansion planned before 2045.

As shown in Table 7-6 (DWR Table 7-2 Retail [Potable]), Turlock anticipates having surplus potable supply during normal year conditions through 2050.

Table 7-6. Normal Year Supply and Demand Comparison – Potable (DWR Table 7-2 Retail)

Table 7 -7 (DWR Table 7 -2 Retail [Non-Potable]) compares Turlock’s available non -potable supply and demand during a normal year from 2030 to 2050. Turlock’s non -potable supply includes raw water from irrigation wells and recycled water from the Turlock RWQCF. Non-potable supply and demand is assumed to be relatively constant through 2050. The non-potable demand shown includes untreated groundwater used for landscape irrigation at various City parks, as well as recycled water used within Turlock’s service area at TID’s Walnut Energy Center and at the Pedretti Sports Field (refer to Table 6 -8 [DWR Table 6 -4 Retail]). The projected surplus of non-potable supply represents recycled water that will be exported outside of Turlock’s service area for agricultural irrigation. 2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)
Supply totals
(autofill from Submittal
Table 6-9 R)
12,868 12,868 16,007 17,682 17,682
Use totals
(autofill from Submittal
Table 4-2 R)
6,895 7,644 8,393 9,142 9,892
Surplus/(shortfall) 5,973 5,224 7,614 8,540 7,791
NOTES: Projected supply includes both treated groundwater and surface water supplies, as defined in DWR Table 6-9 Retail. Increasing supply totals reflect Turlock and SRWA's future water supply projects, as defined in Chapter 6, that are needed to maintain adequate supply capacity to meet peak demands.

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Table 7-7. Normal Year Supply and Demand Comparison – Non-Potable (DWR Table 7-2 Retail)

7.2.2.2 SRWA
Table 7-8 (DWR Table 7 -2 Wholesale) compares SRWA’s available surface water supply and wholesale demand during a normal year from 2030 to 2050. Consistent with Table 6-18 (DWR Table 6-9 Wholesale), SRWA’s available supply during a normal year is projected to be approximately 7,264 MG in 2030 and up to 9,580 MG by 2045. Available supply of 7,264 MG assumes completion of the SRWA WTP filter capacity study in 2028, which would increase the WTP capacity from 15 MGD up to 19.9 MGD. Available supply of 9,580 MG assumes co mpletion of the SRWA WTP Phase 2 Expansion to 30 MGD prior to 2045. After completion of the WTP Phase 2 Expansion, available supply is limited by maximum annual supply defined in SRWA and TID’s Agreement.

As shown in Table 7-8 (DWR Table 7-2 Wholesale), SRWA anticipates having surplus surface water during normal year conditions to meet wholesale demands through 2050. 2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)
Supply totals
(autofill from Submittal
Table 6-9 R)
4,624 4,624 4,624 4,624 4,624
Use totals
(autofill from Submittal
Table 4-2 R)
480 480 480 480 480
Surplus/(shortfall) 4,144 4,144 4,144 4,144 4,144
NOTES: Non-potable supply includes both Turlock's raw (untreated) groundwater and recycled water. Non-potable use shown includes only uses within Turlock's water service area. Remaining non-potable supply (recycled water) is exported outside of the service area for agricultural irrigation.

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Table 7-8. Normal Year Supply and Demand Comparison – Potable (DWR Table 7-2 Wholesale)

7.2.3 Water Service Reliability – Single Dry Year
During dry years, Turlock’s groundwater supply is not anticipated to be reduced. However, SRWA’s surface water supply is conservatively projected to be reduced to approximately 38 percent of the full water allocation. This projection is based on TID’s lowest water allocation to its customers in recent years (2015), in which TID determined a water allocation of 18 inches per acre, or 38 percent of a full allocation, for all its customers.

Projected water demands during a single dry year are assumed to be consistent with demands during a normal year.

7.2.3.1 City of Turlock
Table 7-9 (DWR Table 7 -3 Retail [Potable]) compares Turlock’s available potable supply and demand during a single dry year from 2030 to 2050. Turlock’s total potable supply during a single dry year is projected to be approximately 9,866 MG in 2030 and up to 13,641 MG in 2050. The increase in supply is due to Turlock’s planned groundwater well and treatment projects planned for 2028 and 2038, as well as the planned SRWA WTP filter capacity study in 2027 , increasing total WTP capacity by 2028, and WTP Phase 2 Expansion planned before 2045.

Despite the significant reduction in surface water from SRWA, Turlock anticipates having surplus supply during single dry year conditions through 2050.

Supply totals
(autofill from Submittal
Table 6-9 W)
7,264 7,264 7,264 9,580 9,580
Use totals
(see OPTIONAL Submittal
Table 4-2 W)
4,322 4,939 5,545 6,227 6,691
Surplus/(shortfall) 2,942 2,324 1,719 3,353 2,890
NOTES: Projected wholesale supply available during normal year conditions is based on Table 6-18 (DWR Table 6-9 Wholesale). Projected wholesale use is based on the Cities of Turlock and Ceres' projected surface water use defined in Table 4-5 (DWR Table 4-2 Wholesale). Actual surface water supply availability and purchases may vary based on hydrologic condition, timing of future SRWA projects, and retail demands.
2045 (MG) 2050 (MG) 2030 (MG) 2035 (MG) 2040 (MG)

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Table 7-9. Single Dry Year Supply and Demand Comparison - Potable (DWR Table 7-3 Retail)

Table 7-10 (DWR Table 7 -3 Retail [Non-Potable]) compares Turlock’s available non -potable supply and demand during a single dry year from 2030 to 2050. During a single dry year, non -potable groundwater and recycled water supply and demand are not anticipated to change from normal year conditions .

Therefore, the available supply and demand shown is consistent with Table 7-7 (DWR Table 7 -2 Retail [Non-Potable]).

Table 7-10. Single Dry Year Supply and Demand Comparison – Non-Potable (DWR Table 7-3 Retail)

7.2.3.2 SRWA
Table 7-11 (DWR Table 7-3 Wholesale) compares SRWA’s available surface water supply and wholesale demand during a single dry year from 2030 to 2050. SRWA’s available supply during a single dry year is projected to be approximately 2,760 MG in 2030 and up to 3,715 MG in 2050.

Table 7-11 (DWR Table 7-3 Wholesale) shows that in dry years with significantly reduced surface water allocations like the 2015 drought year, SRWA’s supply will be insufficient to meet the Cities’ projected normal year surface water demands. In these years, the Cities will meet this shortfall by relying on their groundwater wells to meet the remaining water demand. The Cities may also implement demand Supply totals 9,866 9,866 13,005 13,641 13,641
Use totals 6,895 7,644 8,393 9,142 9,892
Surplus/(shortfall) 2,971 2,222 4,612 4,499 3,750
2030 (MG)
NOTES: Supply totals includes both Turlock's groundwater and surface water allocation expected during a single dry year. Under a single dry year, it is conservatively assumed that Turlock may receive only 38 percent of its requested surface water allocation from TID (refer to Table 7-3). Potable use totals are defined in DWR Table 7-2 Retail (Potable). Groundwater supply is not restricted during dry years. Increasing supply totals through 2050 reflect Turlock and SRWA's future water supply projects, as defined in Chapter 6, that are needed to maintain adequate supply capacity to meet peak demands. 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)
Supply totals 4,624 4,624 4,624 4,624 4,624
Use totals 480 480 480 480 480
Surplus/(shortfall) 4,144 4,144 4,144 4,144 4,144
2030 (MG)
NOTES: Non-potable supply includes both Turlock's raw (untreated) groundwater and recycled water.

Non-potable supplies are not anticipated to be reduced during dry years. Non-potable use shown includes only uses within Turlock's water service area. Remaining non-potable supply (recycled water) is exported outside of the service area for agricultural irrigation. 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)

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management measures from their WSCPs as needed . Further discussion on the Cities’ groundwater supplies and their adequacy to meet water demands is addressed in Section 7.4.

Table 7-11. Single Dry Year Supply and Demand Comparison (DWR Table 7-3 Wholesale)

7.2.4 Water Service Reliability – Five-Consecutive-Year Drought During a five-consecutive-year drought, Turlock’s groundwater supply is not anticipated to be reduced.

However, based on the historical five-consecutive-year drought between 2012 and 2016, SRWA’s surface water allocations from TID are projected to be reduced to approximately 63 percent of full allocation in the first year, followed by a reduction to 71 percent of ful l allocation in the second year, 42 percent full allocation in the third year, 38 percent of full allocation in the fourth year, and 75 percent of full allocation in the fifth year.

Projected water demands during a five-consecutive-year drought are assumed to be consistent with those shown during a normal year.

7.2.4.1 City of Turlock
Table 7-12 (DWR Table 7 -4 Retail [Potable]) compares Turlock’s available potable supply and demand during a five-consecutive-year drought between the period of 2030 to 2050.

Despite the significant reduction in surface water from SRWA, Turlock anticipates having surplus supply during a five-consecutive-year drought through 2050.
2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)
Supply totals 2,760 2,760 2,760 3,715 3,715
Use totals 4,322 4,939 5,545 6,227 6,691
Surplus/(shortfall) (1,562) (2,179) (2,785) (2,512) (2,976) NOTES: Under a single dry year, it is conservatively assumed that SRWA may receive only 38 percent of its requested surface water allocation from TID (refer to Table 7-5 [DWR Table 7-1 Wholesale]). The shortfall in surface water supply will be met by the Cities of Turlock and Ceres' groundwater wells.

DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

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Table 7-12. Multiple Dry Years Supply and Demand Comparison – Potable (DWR Table 7-4 Retail)

Table 7-13 (DWR Table 7 -4 Retail [Non-Potable]) compares Turlock’s available non -potable supply and demand during a five -consecutive-year drought between the period of 2030 to 2050 . During a five - consecutive-year drought, non -potable groundwater and recycled water supply and demand are not anticipated to change from normal year conditions. Therefore, the available supply and demand shown is consistent with Table 7-7 (DWR Table 7-2 Retail [Non-Potable]). 2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)
Supply totals 11,077 11,077 14,216 15,271 15,271
Use totals 6,895 7,644 8,393 9,142 9,892
Surplus/(shortfall) 4,182 3,433 5,822 6,129 5,379
Supply totals 11,464 11,464 15,792 15,792 15,792
Use totals 7,045 7,794 8,543 9,292 9,892
Surplus/(shortfall) 4,419 3,670 7,249 6,500 5,901
Supply totals 10,060 10,060 13,902 13,902 13,902
Use totals 7,194 7,944 8,693 9,442 9,892
Surplus/(shortfall) 2,865 2,116 5,209 4,460 4,011
Supply totals 9,866 13,005 13,641 13,641 13,641
Use totals 7,344 8,093 8,843 9,592 9,892
Surplus/(shortfall) 2,522 4,912 4,799 4,050 3,750
Supply totals 11,658 14,797 16,053 16,053 16,053
Use totals 7,494 8,243 8,992 9,742 9,892
Surplus/(shortfall) 4,164 6,553 7,060 6,311 6,161
First year
Second year
Third year
Fourth year
Fifth year
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

NOTES: Increasing supply totals reflect Turlock and SRWA's future water supply projects, as defined in Chapter 6, that are needed to maintain adequate supply capacity to meet peak demands. The SRWA WTP Phase 2 Expansion is anticipated in 2041 for the purposes of this table, which will increase the WTP capacity from 19.9 MGD to 30 MGD.

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Table 7-13. Multiple Dry Years Supply and Demand Comparison – Non-Potable (DWR Table 7-4 Retail)

7.2.4.2 SRWA
Table 7-14 (DWR Table 7 -4 Wholesale) compares SRWA’s available surface water supply and wholesale demand during a five-consecutive-year drought between the period of 2030 to 2050.

Table 7-14 (DWR Table 7 -4 Wholesale) shows that in some dry years with significantly reduced surface water allocations, SRWA’s supply will be insufficient to meet the Cities’ projected normal year surface water demands. In these years, the Cities will meet this shortfall by relying on their groundwater wells to meet the remaining water demand. The Cities may also implement demand management measures from their WSCPs as needed. Further discussion on the Cities’ groundwater supplies and their adequacy to meet demands is addressed in Section 7.4.
2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)
Supply totals 4,624 4,624 4,624 4,624 4,624
Use totals 480 480 480 480 480
Surplus/(shortfall) 4,144 4,144 4,144 4,144 4,144
Supply totals 4,624 4,624 4,624 4,624 4,624
Use totals 480 480 480 480 480
Surplus/(shortfall) 4,144 4,144 4,144 4,144 4,144
Supply totals 4,624 4,624 4,624 4,624 4,624
Use totals 480 480 480 480 480
Surplus/(shortfall) 4,144 4,144 4,144 4,144 4,144
Supply totals 4,624 4,624 4,624 4,624 4,624
Use totals 480 480 480 480 480
Surplus/(shortfall) 4,144 4,144 4,144 4,144 4,144
Supply totals 4,624 4,624 4,624 4,624 4,624
Use totals 480 480 480 480 480
Surplus/(shortfall) 4,144 4,144 4,144 4,144 4,144
First year
Second year
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

Third year
Fourth year
Fifth year

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Table 7-14. Multiple Dry Years Supply and Demand Comparison (DWR Table 7-4 Wholesale)

7.3 DROUGHT RISK ASSESSMENT
CWC §10635(b) requires that Turlock and SRWA prepare a DRA based on the supply condition associated with the five driest consecutive years on record. This supply condition is to be assumed to occur over the next five years, from 2026 through 2030.

For the purposes of this DRA, Turlock’s raw water and recycled water supplies are assumed to be sufficient to meet non-potable demands and therefore are excluded from the DRA and its associated table (DWR Table 7-5 Retail [Non-Potable]). The DRA will only be performed for Turlock and SRWA’s potable water supplies. This section reviews the data and methods used to define the DRA water shortage condition and evaluates each potable water source’s reliability under the assumed drought condi tion. Total potable water supplies during the five-year drought are compared to projected potable water demands.

This DRA prepares Turlock and SRWA for a potential potable water shortage and for implementation of its WSCP, if necessary.

7.3.1 Data, Methods, and Basis for Water Shortage Condition Turlock and SRWA’s DRA was performed for 202 6 through 2030 using the same five -consecutive-year drought conditions (2012 through 2016) presented in Section 7.2.4. A summary of the data and basis for the water shortage condition is provided in this section.

Supply totals 4,576 4,576 4,576 6,159 6,159
Use totals 4,322 4,939 5,545 6,227 6,691
Surplus/(shortfall) 254 (363) (969) (68) (532)
Supply totals 5,157 5,157 6,941 6,941 6,941
Use totals 4,445 5,060 5,681 6,320 6,691
Surplus/(shortfall) 712 97 1,260 621 250
Supply totals 3,051 3,051 4,106 4,106 4,106
Use totals 4,569 5,181 5,818 6,413 6,691
Surplus/(shortfall) (1,518) (2,131) (1,712) (2,307) (2,585) Supply totals 2,760 2,760 3,715 3,715 3,715
Use totals 4,692 5,303 5,954 6,505 6,691
Surplus/(shortfall) (1,932) (2,542) (2,239) (2,791) (2,976) Supply totals 5,448 5,448 7,332 7,332 7,332
Use totals 4,816 5,424 6,091 6,598 6,691
Surplus/(shortfall) 632 24 1,241 734 641
NOTES: Per DWR Table 6-7 Wholesale, the SRWA WTP Phase 2 Expansion to 30 MGD capacity is anticipated between 2041 to 2045. For the purposes of this table, it is assumed to be completed in 2041.

Third year
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

Fourth year
Fifth year
First year
Second year
2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)

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7.3.1.1 City of Turlock
Turlock’s projected potable water demands for 2026 to 2029 were linearly interpolated between actual 2025 potable water demand of 6,146 MG and projected 2030 potable water demand of 6,895 MG (Table 4-6).

Table 7-15 summarizes Turlock’s anticipated potable supplies f or each year of the DRA . As previously discussed, Turlock’s groundwater supply is not anticipated to be reduced during drought years. Available groundwater supply is projected to be 6,456 MG in 2026 and 2027 and increasing to 8,026 MG in 2028 due to Turlock’s planned groundwater well projects defined in Chapter 6.

The SRWA WTP capacity is 15 MGD in 2026 (10 MGD allocated to Turlock) and anticipated to be expanded to 19.9 MGD by 2028 (13.3 MGD allocated to Turlock) due to the filter capacity study. Consistent with the five-consecutive-year drought in Section 7.2.4, Turlock’s surface water supply from SRWA for the DRA is based on TID’s water allocations for the most recent five -consecutive-year drought (2012 -2016).

Therefore, SRWA’s allocations from TID are projected to be reduced to approximately 63 percent of full allocation in 2026, followed by a reduction to 71 percent of full allocation in 2027, 42 percent full allocation in 2028, 38 percent of full allocation in 2029, and 75 percent of full allocation in 2030.

Table 7-15. Turlock’s Projected Potable Water Supplies for Drought Risk Assessment – Retail (MG) Supply Source
2026
(Year 1)
2027
(Year 2)
2028
(Year 3)
2029
(Year 4)
2030
(Year 5)
Groundwater(a) 6,456 6,456 8,026 8,026 8,026
Purchased surface water from SRWA(b) 2,300 3,438 2,034 1,840 3,632 Total 8,756 9,894 10,060 9,866 11,658
(a) Turlock’s groundwater supply is not anticipated to be reduced during drought years. (b) Surface water supply allocations assumed to be reduced in equal proportion to TID’s allocations during the 2012 to 2016 drought as shown in Table 7-4.

7.3.1.2 SRWA
SRWA’s projected wholesale surface water demands for 2026 through 2030 are based on projections provided by SRWA’s wholesale customers (i.e. the Cities).

Table 7-16 summarizes SRWA’s anticipated available surface water supplies for each year of the DRA .

Consistent with Turlock’s DRA, the SRWA WTP capacity is 15 MGD in 2026 and anticipated to be expanded to 19.9 MGD by 2028 due to the filter capacity study expected to be completed in 2027 . Surface water allocations are anticipated to be reduced by TID consistent with the five -consecutive-year drought described in Section 7.2.4.

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Table 7-16. SRWA’s Projected Potable Water Supplies for Drought Risk Assessment – Wholesale (MG)
Supply Source
2026
(Year 1)
2027
(Year 2)
2028
(Year 3)
2029
(Year 4)
2030
(Year 5)
Tuolumne River surface water(a) 3,449 5,157 3,051 2,760 5,448 (a) Surface water supply allocations assumed to be reduced in equal proportion to TID’s allocations during the 2012 to 2016 drought as shown in Table 7-4. SRWA’s WTP filter capacity study anticipated to be completed in 2027 with additional capacity available beginning in 2028.

7.3.2 DRA Water Source Reliability
The City of Turlock’s potable water supplies include local groundwater, which is not anticipated to be impacted during drought periods, and surface water purchased from SRWA. Surface water from SRWA is anticipated to be reduced during drought periods as discussed in Section 7.3.1. During these periods, Turlock will use additional groundwater supplies to meet the remaining demand.

SRWA’s sole water source for its wholesale customers is TID surface water. SRWA and its customers recognize that in drought years, water deliveries from TID could be reduced significantly. For this reason, they maintain adequate supply capacity from their groundwater wells to supplement water supply from SRWA during drought periods.

7.3.3 Total Water Supply and Use Comparison

7.3.3.1 City of Turlock
As shown in Table 7 -17 (DWR Table 7 -5 Retail), during a five -year drought beginning in 202 6, Turlock’s potable water supply is projected to be adequate to meet projected potable water demands through 2030, even without water conservation. However, Turlock may implement water conservation and demand management measures as mandated by the State during a state-wide drought emergency declaration.

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Table 7-17. Five Year Drought Risk Assessment Tables to Address Water Code Section 10635(b) (DWR Table 7-5 Retail)

7.3.3.2 SRWA
As shown in Table 7-18 (DWR Table 7-5 Wholesale), during a five-year drought beginning in 2026, SRWA’s supplies do not meet projected demands for the first, third, and fourth year of the representative five-year drought. For years with significantly reduced surface water allocations, the Cities will meet this shortfall by relying on their existing groundwater supplies to meet the remaining water demand . S ome combination of retail demand reduction efforts and SRWA’s possible purchase or transfer of alternative Tuolumne River water supplies may also be used to meet this shortfall. 2026 Total
Total Water Use (MG) 6,295
Total Supplies (MG) 8,756
Surplus/Shortfall w/o WSCP Action 2,461
2027 Total
Total Water Use (MG) 6,445
Total Supplies (MG) 9,894
Surplus/Shortfall w/o WSCP Action 3,450
2028 Total
Total Water Use (MG) 6,595
Total Supplies (MG) 10,060
Surplus/Shortfall w/o WSCP Action 3,465
2029 Total
Total Water Use (MG) 6,745
Total Supplies (MG) 9,866
Surplus/Shortfall w/o WSCP Action 3,121
2030 Total
Total Water Use (MG) 6,895
Total Supplies (MG) 11,658
Surplus/Shortfall w/o WSCP Action 4,763
DWR NOTES: Units of measure (AF, CCF, MG) must remain
consistent throughout the UWMP as reported in Submittal Table 2-3.

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Table 7-18. Five Year Drought Risk Assessment Tables to Address Water Code Section 10635(b) (DWR Table 7-5 Wholesale)

7.4 WATER MANAGEMENT TOOLS AND OPTIONS
SRWA and the Cities of Turlock and Ceres utilize a conjunctive use strategy that aims to maximize surface water use while relying on their groundwater wells to meet peak demands and demands during water shortage events. As of 2025, Turlock’s total groundwater well capacity is approximately 34.8 MGD, and Ceres’ capacity is approximately 11.0 MGD. 4 The Cities’ existing groundwater supplies and planned improvements are detailed in their respective 2025 WMPs. For water system operational purposes, both Cities maintain minimum production rates for their wells. Groundwater supplies will continue to be an important asset to be used in conjunction with SRWA’s surface water, especially during dry years when surface water allocations are reduced.

The Cities plan to maintain adequate groundwater well capacity to meet demands even with significant reductions in surface water allocations. The Cities’ 2025 WMPs evaluated the need for additional wells to meet future demands during years with significant surface water reductions, and these projects are now incorporated into the Cities’ long-term capital improvement plans.

4 Groundwater well capacities are based on the City of Turlock 2025 Water Master Plan, and City of Ceres 2025 Water Master Plan.
2026 Total
Total Water Use (MG) 3,659
Total Supplies (MG) 3,449
Surplus/Shortfall w/o WSCP Action (210)
2027 Total
Total Water Use (MG) 3,808
Total Supplies (MG) 5,157
Surplus/Shortfall w/o WSCP Action 1,349
2028 Total
Total Water Use (MG) 3,950
Total Supplies (MG) 3,051
Surplus/Shortfall w/o WSCP Action (899)
2029 Total
Total Water Use (MG) 4,131
Total Supplies (MG) 2,760
Surplus/Shortfall w/o WSCP Action (1,370)
2030 Total
Total Water Use (MG) 4,322
Total Supplies (MG) 5,448
Surplus/Shortfall w/o WSCP Action 1,126
DWR NOTES: Units of measure (AF, CCF, MG) must remain
consistent throughout the UWMP as reported in Submittal Table 2-3.

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To maintain reliable groundwater supplies, the Cities will continue to maintain existing wells and replace or rehabilitate aging wells. Additionally, the Cities plan to construct new groundwater wells as new development increases system demand. As describe d in Chapter 6, the City of Turlock plans to install arsenic treatment on two existing wells in the next few years, and to construct six new wells with treatment by approximately 2040. These improvements will allow Turlock to meet increasing water demands through 2050, even during years with significantly reduced surface water supply. Similarly, the City of Ceres has been actively rehabilitating existing wells with wellhead treatment to maintain compliance with increasingly stringent water quality regulatio ns. Ceres also has plans to rehabilitate aging wells and construct new wells for their planned Copper Trails Specific Plan and West Landing Specific Plan developments. 5
SRWA’s planned projects, including the WTP filter capacity study and Phase 2 expansion, will provide additional surface water supply capacity to help meet the Cities’ future demands. During dry years with significantly reduced surface water allocations from TID, SRWA may explore possibilities for purchases or transfers of temporary supplemental water supplies from TID customers or other senior water right holders.

When shortfalls exist between SRWA surface water supplies and the Cities’ demands, the Cities are primarily responsible for addressing shortfalls through some combination of demand management measures and increased reliance on groundwater supplies. During these dry periods, the Cities may also implement additional demand management measures as defined in their respective WSCPs.

5 City of Ceres. March 2025. Water Master Plan Update.

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CHAPTER 8
Water Shortage Contingency Plan
This chapter discusses Turlock and SRWA’s individual WSCPs, seismic risk to Turlock and SRWA’s water system facilities, and WSCP adoption procedures. To allow for WSCP updates to be made outside of the UWMP preparation process, Turlock and SRWA’s WSCPs are included in this plan separately as Appendix G and Appendix H, respectively.

8.1 BACKGROUND
Water shortages occur whenever the available water supply cannot meet the normally expected customer water use. Th ese shortages can be due to several reasons, including climate change, drought, and catastrophic events. Drought, regulatory action constraints, and natural and manmade disasters may occur at any time. A WSCP presents how an urban water supplier plans to respond to a water shortage condition and helps prevent catastrophic service disruptions.

In 2018, the California State Legislature enacted two policy bills, SB 606 (Hertzberg) and AB 1668 (Friedman) (2018 Water Conservation Legislation), to establish a new foundation for long -term improvements in water conservation and drought planning to adapt to climate change and the resulting longer and more intense droughts in California. The 2018 Water Conservation Legislation set new requirements for water shortage contingency planning; Turlock and SRWA’s WSCPs have been prepared to be consistent with these requirements.

8.2 WATER SHORTAGE CONTINGENCY PLAN
Turlock and SRWA’s WSCPs were developed to provide a strategic plan for preparing and responding to water shortages. The WSCPs include water shortage stages and associated shortage response actions, as well as Turlock and SRWA’s respective legal authorities, communication protocols, compliance and enforcement, and monitoring and reporting.

Turlock has made some updates to its 2020 WSCP with the preparation of this Joint 2025 UWMP to reflect Turlock’s new surface water source from SRWA.

As SRWA recently developed its WSCP in 2024 during preparation of its 2020 UWMP, no changes to SRWA’s WSCP have been made. SRWA’s WSCP was adopted on October 17, 2024 as detailed in Section 8.4. The WSCP has been reviewed in light of the SRWA’s current water supply reliability analysis and determined that it sufficiently enables SRWA to prepare for and respond to the State’s standard water shortage levels.

Turlock and SRWA intend for its WSCP s to be adaptive management plan s so that they may assess response action effectiveness and adapt to foreseeable and unforeseeable events. Therefore, Turlock and SRWA’s WSCPs are included in this plan separately as Appendix G and Appendix H, respectively, to allow for updates to be made outside of the UWMP update preparation process. When an update to either of the WSCPs is proposed, the revised WSCP will undergo the process described in Section 8.3.

8.3 WATER SUPPLY RELIABILITY ANALYSIS
This section provides the water supply planning analysis and reliability findings from this Joint UWMP. The discussion below includes a summary of Turlock and SRWA’s existing and projected water use (from Chapter 4 of the Joint UWMP), existing and planned water supplies by source (from Chapter 6), and the water supply reliability assessment and the Drought Risk Assessment (from Chapter 7).

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Water Shortage Contingency Plan

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This Joint UWMP indicates that Turlock can reliably meet their projected demands through 2050 in both normal and dry years. For a five-year drought (i.e., the Drought Risk Assessment and multiple dry years), no water supply shortfalls are anticipated for Turlock. In response to any supply shortfalls that may occur, Turlock may declare a water shortage condition (as described in Turlock’s WSCP, Appendix G).

For SRWA, the water service reliability assessment and drought risk assessment show that in dry years with significantly reduced surface water allocations like the 2015 drought year, SRWA’s supply will be insufficient to meet the Cities’ projected normal year surface water demands. In these years, the Cities will meet this shortfall by relying on their groundwater wells to meet the remaining water demand.

Climate conditions, regional and statewide water supply conditions, and actions by surrounding agencies may impact Turlock and SRWA’s available water supply. A water shortage condition occurs when the supply of potable water available cannot meet ordinary water demands for human health and safety .

Turlock and SRWA may be able to foresee its water shortage condition in some cases, but an unforeseen sudden or emergency event (e.g., power outage or earthquake) may also cause a water shortage . In general, Turlock and SRWA’s water supply conditions may be affected by the following:
• Groundwater quality
• Local surface water availability (TID allocations on the Tuolumne River) • Changing environmental and regulatory requirements (Bay-Delta Plan, FERC licensing, groundwater contaminant limits, etc.)
• Climate change
Turlock plans for potential drought events annually. Turlock conducts an annual water supply and demand assessment in accordance with its WSCP to determine its water supply conditions for the current year and a potential subsequent dry year. The analysis conducted is in the context of Turlock and SRWA’s water supply sources and reliability.

Seismic events present potential water supply interruptions due to infrastructure failure. Because earthquakes are common, well -tracked, and recognized as high -probability occurrences in California, UWMPs are required to include a seismic risk assessment and mitigation plan. Turlock and SRWA’s plans are described in the section below.

8.3.1 Seismic Risk Assessment and Mitigation Plan
CWC §10632.5(a) requires that UWMPs also include a seismic risk assessment and mitigation plan to assess and mitigate a water system’s seismic vulnerabilities. A Local Hazard Mitigation Plan (LHMP) or Risk and Resilience Assessment (RRA) may be incorporated in this UWMP t o meet this requirement if it addresses seismic risk.

Turlock and SRWA’s service area is located within Stanislaus County. As such, the Stanislaus County Multi-Jurisdictional HMP (Stanislaus County HMP, updated in November 2022), provides relevant information regarding local seismic risk and is incorporated herein by reference. The 2022 Stanislaus County HMP is available on the Stanislaus County website , and incorporated in this plan by reference :
https://oes.stancounty.gov/divisions/emergency-management/multi-jurisdictional-hazard-mitigation-plan). The Stanislaus County HMP was adopted in November 2022 and submitted to the Federal Emergency Management Agency, which found it in conformance with Title 44 Code of Federal Regulations Part 201.6 Local Mitigation Plans. The HMP is required to be updated every five years.

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Seismic activity within Stanislaus County has been historically rare, and there are no records of major seismic activity originating in the County. As described in the Stanislaus County HMP, there are no known active faults within the County . However, ground shaking from earthquakes with epicenters elsewhere have been felt; most recently in 2021 by the 6.0 magnitude on the Richter Scale earthquake centered in the Little Antelope Valley, in Mono County.

Nearby faults that are the principal sources of seismic activity affecting Stanislaus County are the San Andreas to the west; the Hayward and Calaveras faults to the northwest; the White Wolf, Garlock, and Sierra Nevada faults to the south; and the Bear Mountain Fault Zone east of Merced County. Most of the historic earthquakes that have impacted Stanislaus County had epicenters that occurred along the San Andreas and Hayward faults to the west of the County.

Turlock’s water storage, treatment, and pumping facilities have been constructed to meet earthquake safety standards and are inspected regularly. Additionally, s ince SRWA’s facilities were designed and constructed within the last decade, the facilities were constructed to meet and exceed the most recent seismic requirements in the building code.

Turlock and SRWA ha ve implemented efforts in addressing their facilities’ seismic vulnerabilities. In accordance with America’s Water Infrastructure Act (AWIA), Turlock and SRWA prepar ed a risk and resilience assessment (RRA) of its water systems and self-certified their individual RRAs with the United States Environmental Protection Agency in 2025. The RRA systematically evaluated Turlock and SRWA’s assets, threats, and risks, as well as countermeasures that might be implemented to minimize overall risk to the system. Vulnerability to natural hazards, including earthquakes, was assessed based on Turlock and SRWA’s level of preparation/resilience, active response capability, and ability to recover. To ensure the security of Turlock and SRWA’s water facilities, the RRAs will be retained as confidential documents.

8.4 PLAN ADOPTION, SUBMITTAL, AND AVAILABILITY
SRWA’s WSCP was adopted concurrently with its 2020 UWMP on October 17, 2024 by separate resolution.

Turlock’s WSCP (Appendix G) is adopted concurrently with this Joint 2025 UWMP, by separate resolution.

Prior to adoption, a duly noticed public hearing was conducted. An electronic copy of SRWA’s WSCP was submitted to DWR in 2024. An electronic copy of the Turlock WSCP will be submitted to DWR within 30 days of adoption.

No later than 30 days after adoption, an electronic copy of Turlock’s WSCP will be available for public review and download on Turlock’s website, https://blog.cityofturlock.org/watersewergarbageservice/ and will be provided to Stanislaus County. SRWA’s WSCP is available on its website, https://www.stanrwa.com/ and was provided to Stanislaus County.

Turlock and SRWA’s WSCPs are adaptive management plans and are subject to refinements as needed to ensure that the shortage response actions and mitigation strategies are effective and produce the desired results. When a revised WSCP is proposed, the revised WSCP will undergo the process described above for adoption by Turlock City Council and/or SRWA’s Board, and distribution to Stanislaus County, DWR, Turlock and SRWA’s water customers, and the general public.

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CHAPTER 9
Demand Management Measures
SRWA and Turlock implement DMMs to sustainably manage their water resources. If water demands are not managed, water service reliability may be reduced due to increases in water demand, and/or changes in water supplies associated with climate change and ot her factors. The implementation of DMMs can help improve water service reliability and help meet Turlock’s and State water conservation goals. This chapter describes SRWA’s DMMs as a wholesale supplier, as well as Turlock’s implementation of DMMs in the past five years and continued plans for implementing and monitoring its water conservation program.

9.1 DEMAND MANAGEMENT MEASURES FOR WHOLESALE SUPPLIERS
As discussed in Chapter 6, SRWA provides treated surface water supply to its retailers on a wholesale basis. Since beginning water deliveries in November 2023, SRWA has continued to implement DMMs within its service area. The wholesale agency DMMs discussed in this Joint UWMP include the following:
• Metering
• Public education and outreach
• Water conservation program coordination and staffing support • Other DMMs
In addition, a narrative of asset management and wholesale supplier assistance programs is provided.

For each DMM, the current program is described, followed by a description of how the DMM has and will be implemented.

9.1.1 Metering
SRWA fully meters all water before and after treatment at the WTP, as well as immediately before introduction into its wholesale customers’ distribution systems. SRWA also compares these numbers to those measured by its wholesale customers to ensure parity. In the event that SRWA’s meter readings do not match those of its wholesale customers, SRWA will inspect all meters to ensure that they are within tolerance limits. Since beginning water deliveries in November 2023, SRWA’s water meter readings have matched that of their wholesale customers. To ensure continued meter reading accuracy, SRWA contracts with a third-party to verify meter accuracy annually.

9.1.2 Public Education and Outreach
In addition to its wholesale customers’ public education and outreach programs (refer to Section 9.2.4 for Turlock’s public education and outreach programs), SRWA facilitates outreach through providing information on its website (stanrwa.com) and on social media outlets as well as periodically at public Board meetings. SRWA’s commitment to public education and outreach is furthered by the distribution of an annual water quality report completed in conjunction with its wholesale customers.

9.1.3 Water Conservation Program Coordination and Staffing Support SRWA’s staff is closely integrated with the staff of its wholesale customers, the Cities of Turlock and Ceres, to facilitate communication and conservation objectives amongst stakeholders. All voting members of SRWA’s Board of Directors consist of two Turlock City Council members and two City of Ceres City Council members. In addition, SRWA staff hold monthly Technical Advisory Committee meetings with staff from

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the Cities to ensure regular communication on various project s and programs, including water conservation and public outreach coordination.

More information regarding Turlock’s water conservation programs and staff support of the conservation programs can be found in Section 9.2.6. Additional information regarding the City of Ceres ’ water conservation programs can be found in the Ceres 2025 UWMP.

9.1.4 Other Demand Management Measures
SRWA does not have any other DMMs to report.

9.1.5 Asset Management
With the commissioning and start -up of SRWA’s WTP, SRWA has implemented a new Computerized Maintenance Management System (CMMS). The CMMS is in service and is being configured for optimum benefit to SRWA and its operation of the WTP. The configuration will develop asset standards including asset hierarchy; asset classification; and risk factors such as criticality, condition, and risk ratings. The configuration will also develop maintenance standards including work type and work priority. These standards will help SRWA manage assets and prioritize work based on risk and support fiscal planning for long-term rehabilitation and replacement.

Through this effort, SRWA endeavors to maximize production efficiency and minimize system water losses.

9.1.6 Wholesale Supplier Assistance Programs
Although SRWA is not directly involved with urban water demand reduction as a wholesaler , SRWA supports its wholesale customers through on-going and continuous coordination, and promotion of water conservation and public outreach activities as described in Sections 9.1.2 and 9.1.3. SRWA does not have a dedicated DMM assistance program for its wholesale customers.

9.2 DEMAND MANAGEMENT MEASURES FOR RETAIL SUPPLIERS
Since the 2020 UWMP reporting cycle, Turlock continued to implement DMMs within its service area as part of its standard practice. This section summarizes the nature and extent of each of Turlock’s DMMs implemented over the past five years. The following DMMs are discussed in this section:
• Water waste prevention ordinances
• Metering
• Conservation pricing
• Public education and outreach
• Programs to assess and manage distribution system real loss • Water conservation program coordination and staffing support Other DMMs implemented by Turlock that have had significant impacts on water use are also described.

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The adoption of the Making Conservation a California Way of Life Regulation, described in Section 9.4, makes continued implementation of these DMMs a priority for Turlock. This regulation requires increasingly stringent water conservation requirements over time.

9.2.1 Water Waste Prevention Ordinances
Title 6, Chapter 7 of the Turlock Municipal Code includes provisions that prohibit the wasteful use of water. Article 3 of the Chapter provides regulations for:
• irrigation of outdoor landscaping;
• use of water for wash down of r ecreational vehicles, sidewalks, gutters, outside structures, or other exterior surfaces;
• limitations on constant flow of water for "slip -n-slides" and other recreational activities; and,
• use of a quick-acting automatic positive shut-off valve in proper operating condition for vehicle washing.

Further, the Chapter includes provisions that authorize actions associated with emergency water shortage conditions as described in Appendix G of this UWMP.

9.2.1.1 Implementation Over Recent Years
Table 9-1 lists the number of documented water waste violations recorded by Turlock over the past three years. As shown, there was a substantial increase in the number of recorded violations from 2023 to 2025 due to increased enforcement.

Table 9-1. Documented Water Waste Violations(a)
2023 2024 2025
Number of Violations 156 274 633
(a) Written warnings and notices to customers, excludes informal interactions.

9.2.1.2 Implementation to Achieve Water Use Objectives
Implementation of this water waste prevention ordinance DMM is ongoing and will continue to help Turlock achieve its water use objectives by minimizing the non -essential uses of water to increase availability for human consumption, sanitation, and fire protection.

9.2.2 Metering
Turlock commenced meter-based billing for all its water accounts on January 1, 2011. In conjunction with a thorough public education campaign, the move to meter -based billing has resulted in a significant decrease in water consumption.

The installation of meters appears to have significantly modified customer behavior and is largely responsible for the 20 percent reduction in total City-wide water use from 2007 to 2011. The per capita water use, likewise, declined by 22 percent City -wide, 23 percent for single family residential and

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8 percent for multi -family residential, between 2011 and 2015 as customers began receiving and responding to their usage-based monthly water bills.

Turlock plans to upgrade the majority of its existing AMR meters with AMI meters, as many of the existing water meters are reaching the end of their useful life . Meter replacement is important, as older meters may measure water use inaccurately and tend to under-register actual flows, leading to inaccurate billing and consumption data. This project will upgrade all residential meters to AMI in a phased approach.

Phase 1 is expected to begin in 2026 with the overall project anticipated to be completed within approximately 36 months . AMI provides two -way communication and near real -time water use data which can effectively influence customer’s water use behavior . Once fully deployed, AMI will support water use efficiency by improving leak detection, system monitoring, and the timeliness and accuracy of water use information for both the customers and Turlock staff. Once AMI is implemented , City-wide customer water demand is expected to decrease noticeably from current levels of demand.

9.2.2.1 Implementation Over the Past Five Years
Implementation of metering appears to have led to significant reductions in per capita water use. Before meters were installed in 2011, the 2010 per capita water use was 284 GPCD . From 2021 through 2025, the per capita water use ranged from 227 GPCD to 248 GPCD. This recent water use data represents a reduction in per capita water use between 10 to 18 percent compared to the 2010 value of 284 GPCD before meters were installed . With this per capita water use reduction, Turlock was able to meet its SB X7-7 2020 water use target.

9.2.2.2 Implementation to Achieve Water Use Objectives
Implementation of this metering DMM is ongoing and will continue to help Turlock achieve its water use objectives by providing accurate water use information for the individual customer and Turlock as a whole. The implementation of AMI for residential meters is expected to further improve water use tracking and transparency for customers and Turlock.

9.2.3 Conservation Pricing
In 2017, Turlock, in conjunction with its consultant, Municipal Financial Services, prepared a water rate study to determine the adequacy of rates to meet projected expenditures of its water enterprise fund.

Based on the findings of the study, Turlock subsequently adopted a five-year water rate increase schedule that went into effect March 1 st of 2018 . The final water rate increase of that schedule took effect January 1, 2022. Turlock’s current water rates are available on Turlock’s website at https://www.cityofturlock.org/watersewergarbageservice/billspayments/utilityservicerates/ .

The current pricing structure is comprised of three components. The first is the commodity charge (i.e., usage charge), which is the cost of the water supply. Customers are charged per 1,000 gallons of water based on the account type. This component of the pricing structure provides financial incentivizes customers to conserve. The second component of the pricing structure is the capacity charge. This charge accounts for the cost of the meter, operation and maintenance, as well as other facility costs. This charge is based on the meter size. The third component of the pricing structure is the customer charge, which accounts for the cost of mailing and processing bills along with other administrative costs. The customer charge is the same amount regardless of meter size or account type.

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Turlock is currently developing an updated water rate study to evaluate improved conservation pricing during water shortage reductions and to ensure that water rates are adequate to meet projected expenditures. Turlock currently plans to implement these updated rates in 2027.

9.2.3.1 Implementation Over the Past Five Years
As discussed in Section 9.2.2.1, the installation of water meters and the transition to meter-based billing have significantly reduced per capita water use compared to 2010 levels, prior to metering and meter-based billing.

9.2.3.2 Implementation to Achieve Water Use Objectives
Implementation of this conservation pricing DMM will continue to help Turlock achieve its water use objectives by ensuring water customers pay the true cost of water. Implementation of this DMM will also continue to help adequately fund water system operations and maintenance, including rehabilitation and replacement programs, and water conservation programs.

9.2.4 Public Education and Outreach
Turlock has an active public information and outreach program to promote water conservation . This program consists of distributing information to the public through a variety of methods, such as utility billing publication inserts, press releases via radio and newspaper, school curriculum, educational flyers, commercials on television, social media outreach, and water conservation tips and videos on Turlock’s Water Conservation webpage (https://ci.turlock.ca.us/watersewergarbageservice/waterconservation/).

9.2.4.1 Implementation Over the Past Five Years
Since 2007, Turlock has implemented a prominent environmental stewardship program called “Go Green Week.” Th is broad program focuses on conservation education , with program components inclu ding water use efficiency and conservation, stormwater pollution prevention, recycling, composting, and waste reduction habits.1
“Go Green Week” is Turlock’s primary public education campaign for school-age children, which engages students in activities that teach the importance of environmentally responsible behavior. Now in its nineteenth year, “Go Green Week” is coordinated annually in March with participating schools in Turlock.

Through a partnership of City staff, teachers, administrators, community organizations, and volunteers, students learn about conservation and pollution prevention strategies such as recycling, composting, water conse rvation and wa ste reduction. City staff also conduct periodic classroom presentations on water conservation and other environmental issues, as well as provide student tours of Turlock’s wastewater treatment facility and SRWA’s recently constructed WTP.

Turlock promotes “Go Green Week” and general water conservation public education and outreach via:
• Turlock’s website and social media pages (Facebook and Instagram) • Utility bill inserts
• Press releases

1 City of Turlock. Go Green Week. Accessed at https://www.cityofturlock.org/specialevents/gogreenweek/.

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• Print media campaigns/columns in local newspapers
• Booths at fairs/exhibitions
• Presentation to local service organizations and similar groups

9.2.4.2 Implementation to Achieve Water Use Objectives
Implementation of this public education and outreach DMM is ongoing and will continue to help Turlock achieve its water use objectives by educating water users about the importance of improving water use efficiency and avoiding water waste.

9.2.5 Programs to Assess and Manage Distribution System Real Loss Turlock has an active water loss prevention program that tracks both real and apparent losses which are monitored by staff in the Municipal Services Department. Turlock also tracks typical water system activities associated with water losses including water main breaks; valve, hydrant, or service leaks; and relative accuracy of supply and demand meters.

As discussed previously in Section 4.3, beginning in 2016, water suppliers are required to report distribution system water losses based on the AWWA Water Audit Software. A water audit is a method of accounting water use throughout a water system to quantify unaccounted for water. Unaccounted for water is the difference between metered production and metered usage on a system -wide basis. With the implementation of meter -based billing for all water accounts, Turlock is better able to track water losses and unaccounted for water use.

9.2.5.1 Implementation Over the Past Five Years
Turlock uses AWWA’s software to complete an annual Water Audits and Balance Analysis. Turlock’s water audits from 2020 through 2024 are included in Appendix F.

Implementation of this DMM is ongoing and expected to help Turlock achieve its water use objectives by quickly identifying sources of water loss so repairs can be completed in a timely manner and water losses are minimized. In compliance with the DWR requirement, Turlock will continue to evaluate distribution system losses annually via the AWWA Water Audit Software and report to DWR. Turlock will continue to take actions to reduce water losses by improving metering accuracy and enhancing the overall data quality throughout the system, including a goal of full implementation of AMI before 2030.

In addition to the AWWA water audits, Turlock's water loss prevention program involves leak detection and repair, focusing primarily on areas with a high probability for leakage. Due to the flat nature of the San Joaquin Valley and the shallow depth of Turlock’s water mains, water leaks are detected fairly easily.

Utility staff monitor for water leaks as part of their daily operations and respond to calls from customers concerned about potential leaks. Although Turlock does not perform formal pipeline inspections at regular intervals, these “spot check” inspections help contribute to approximately 100 leak repairs per year.

9.2.5.2 Implementation to Achieve Water Use Objectives
Implementation of this DMM , to assess and manage distribution system real losses, is ongoing and will continue to help Turlock achieve its water use objectives by identifying sources of water loss quickly so repairs can be made and losses minimized.

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9.2.6 Water Conservation Program Coordination and Staffing Support Turlock has designated staff to actively develop, promote, enforce, and maintain water conservation programs. Certain tasks may include responding to water complaints, monitoring water waste, and checking for excess landscape water use.

Turlock has a Water Conservation Specialist/Field Services Technician and a Staff Services Assistant that each allocates approximately 20 hours per week, for a total of 40 hours per week, to implement and monitor Turlock’s water conservation activities. Tu rlock also has additional staff that support Turlock’s water conservation program including a Staff Services Analyst, Regulatory Affairs Manager, and Utilities Manager. Together, these five employees are responsible for implementing and monitoring Turlock’s water conservation activities.

9.2.6.1 Implementation Over the Past Five Years
Over the past five years, Turlock’s water conservation staff have continued to implement and monitor the DMMs discussed in this chapter. In recent years, outreach efforts have been strengthened through more consistent and timely use of social media; previously, outreach relied primarily on the City’s website.

Messaging delivered through bill inserts has been improved, and field enforcement efforts have been increased. The City c ontinues to provide water conservation education and conservation tools to customers at City Hall and through participation in community events.

The effectiveness of this water conservation program support DMM is evaluated in conjunction with the success of Turlock’s water conservation efforts as a whole. Meeting Turlock’s water use objectives is a priority. As Turlock grows and water resources become more limited and expensive, and State water conservation regulations become increasingly stringent, the water conservation programs have increased in priority. As the water conservation program grows, the duties of City staff will increase, and additional staffing may be necessary.

9.2.6.2 Implementation to Achieve Water Use Objectives
Implementation of this DMM is ongoing and will continue to help Turlock achieve its water use objectives by implementing Turlock’s water conservation program and ensuring its effectiveness.

9.2.7 Other Demand Management Measures
In addition to the six DMMs described above, Turlock also implements the following programs:
• Residential Water Survey Program
• Residential High-Efficiency Toilet Rebate Program
• High-Efficiency Washing Machine Rebate Program
• Large Landscape Conservation Program
• Conservation for Commercial and Industrial Accounts
These programs are described below.

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9.2.7.1 Residential Water Survey Program
Turlock began implementation of its residential water survey program in 2010. The program was developed by City staff and consists of offering residential home water survey kits to Turlock’s customers.2 The Home Water Survey Kit allows customers to perform a home water audit, gauging how efficient they are with their water use. By performing the audit, the customer can identify areas of potential improvement, as well as identify potential leaks.

The Home Water Survey Kit shows users how to read their water meter and use it to:
• Detect for leaks
• Evaluate if landscape is being irrigated appropriately • Assess the efficiency of water fixtures and appliances • Identify water saving opportunities
Free water conservation devices ( e.g. low-flow shower heads and faucet aerators) are provided to customers who complete and submit a survey response form to Turlock’s Municipal Services Department.

Customers can request these survey kits online. Turlock also provides these kits directly to customers who are identified to have high water usage.

9.2.7.2 Residential WaterSense Toilet Rebate Program
Turlock’s Municipal Services Department provides incentives for residential customers to replace existing toilets with high efficiency models that meet the EPA’s WaterSense specifications. Turlock offers a rebate of $75 per toilet for the replacement of a 3.6 or greater gallons per flush (gpf) model with one that uses

1.28 gpf or less.3 Replacing a high-water use toilet with a new high efficiency model of 1.28 gpf can save about 38 gallons of water each day.

9.2.7.3 High-Efficiency Washing Machine Rebate Program
Turlock’s Municipal Services Department offers a high-efficiency washing machine rebate program which provides financial incentives to qualifying customers who install high-efficiency washing machines in their homes. A high-efficiency washing machine uses approximately 15 gallons of water per load of laundry, while a standard top-loading washing machine uses about 40 gallons of water per load.

Rebates for the purchase of high -efficiency clothes washers are available for up to $100 per washer. 3 In addition to Turlock’s rebate, Turlock’s main electrical utility (TID) currently offers a $ 50 rebate for customers who purchase a high-efficiency clothes washer (Energy Star compliant).4 These rebates can be combined for additional savings.

2 City of Turlock. Home Water Survey Kit. Accessed at
https://www.cityofturlock.org/watersewergarbageservice/waterconservation/homewatersurveykit.asp 3 City of Turlock. Rebates. Accessed at
https://ci.turlock.ca.us/watersewergarbageservice/waterconservation/rebates.asp. 4 Turlock Irrigation District. Residential Rebates. Accessed at https://www.tid.org/customer-service/rebates-and-savings/residential-rebates/.

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9.2.7.4 Large Landscape Conservation Program
Beginning in 2006, Turlock began monitoring water use of landscape and irrigation customers. This program was further enhanced by the installation of a fixed -based AMR system that allow ed Turlock to monitor water consumption on a daily basis. Turlock has worked with large landscape customers such as the Turlock Unified School District and a number of religious institutions to increase efficiency and reduce overall water use. Turlock has also installed meters and AMR devices at all City parks and City -owned landscaped areas to ensure efficient landscape irrigation.

More recently, Turlock has developed a native, drought -tolerant plant initiative for implementation in 2026 at three different locations throughout the City. Turlock continues to provide useful resources for landscaping and reducing landscape irrigation water demand on its website (https://www.cityofturlock.org/buildinginturlock/landscaping/ ).

9.2.7.5 Conservation for Commercial and Industrial Accounts Turlock’s commercial, institutional, and industrial (CII) customers’ sewer rates include both a monthly fixed service charge and a volumetric charge. In comparison, residential customers’ sewer rates include only a monthly fixed service charge. This structure provides a significant financial incentive for CII customers to conserve water, since reductions in water use lower both their water and sewer service costs.

Following the Regional Water Quality Control Board’s (Regional Board’s) requirement that Turlock upgrade its RWQCF to disinfected tertiary treatment, Turlock’s sewer rates increased and are now greater than its potable water rates. As a result, high volumetric sewer charges further encourage CII customers to adopt water -efficient practices . Every reduction in metered water use directly reduces their sewer costs.

Turlock’s Environmental Compliance Inspector reviews CII water meter readings on a monthly basis, and conducts annual inspections of all significant industrial users. By analyzing meter data and production processes, Turlock’s Environmental Compliance Inspector has been able to reduce water consumption for a variety of CII accounts.

9.3 MEMBER OF THE CALIFORNIA WATER EFFICIENCY PARTNERSHIP Turlock is an active member of the California Water Efficiency Partnership ( CalWEP) establishing a firm commitment to the implementation of DMMs to conserve its water supplies . Turlock plans to continue implementation of its DMMs into the future. Turlock also plans to comply with the Making Conservation a California Way of Life Regulation to meet its Urban Water Use Objectives (UWUOs), and with SB 555 water loss performance standards as part of its Water Loss Control Program.

Other DMMs may be implemented by Turlock (subject to City Council approval) as deemed necessary based on customer participation, water savings, cost effectiveness, and other relevant factors.

9.4 MEETING URBAN WATER USE OBJECTIVES
The Making Conservation a California Way of Life Legislation established a new framework for improvements in long -term urban water use efficiency. This Legislation builds on the statewide 2020 water conservation targets set under SB X7-7 (CWC §10609.2(d)). Under the Legislation, the State Water Board, in coordination with DWR, was required to adopt urban water use efficiency standards, variances, and performance measures by June 30, 2022.