Agenda packet — Patterson City Council, June 16, 2026 (part 3 of 3)

Table 13-5: Applicability of RMSs in Adapting to Climate Change Vulnerabilities Resource Management Strategies
Water DemandWater SupplyWater QualityFlood ManagementEcosystem and Habitat Hydropower Reduce Water Demand
Agricultural Water Use Efficiency   
Urban Water Use Efficiency   
Improve Operational Efficiency and Transfers
Conveyance-Delta    
Conveyance-Regional/Local    
System Reoperation   
Water Transfers  
Increase Water Supply
Conjunctive Management and Groundwater   
Packet Pg. 710
2019 Westside-San Joaquin Integrated Regional Water
Management Plan Chapter 13 Climate Change
Final
January 2019 13-20
Resource Management Strategies
Water DemandWater SupplyWater QualityFlood ManagementEcosystem and Habitat Hydropower Desalination 
Precipitation Enhancement  
Recycled Municipal Water  
Surface Storage-CALFED     
Surface Storage-Regional/Local     
Improve Water Quality
Drinking Water Treatment and Distribution  
Groundwater Remediation/Aquifer Remediation  
Matching Water Quality to Use   
Pollution Prevention   
Salt and Salinity Management   
Urban Stormwater Runoff Management    
Practice Resource Stewardship
Agricultural Land Stewardship    
Ecosystem Restoration     
Forest Management*    
Land Use Planning and Management    
Recharge Areas Protection   
Sediment Management     
Watershed Management      
People and Water
Economic Incentives      
Outreach and Engagement      
Water and Culture   
Water-Dependent Recreation   
Improve Flood Management
Flood Management    
Other Strategies
Crop Idling for Water Transfers*   
Dewvaporation or Atmospheric Pressure
Desalination*  
Packet Pg. 711
2019 Westside-San Joaquin Integrated Regional Water
Management Plan Chapter 13 Climate Change
Final
January 2019 13-21
Resource Management Strategies
Water DemandWater SupplyWater QualityFlood ManagementEcosystem and Habitat Hydropower Fog Collection* 
Irrigated Land Retirement*  
Rainfed Agriculture*  
Waterbag Transport/Storage Technology*   
*These strategies were not included when developing objectives or evaluating projects as they either do not apply to the WSJ IRWMP Region, or would not be considered in the Region unless all other RMSs had been exhausted, as discussed in Chapter 4.

13.5 Plans for Future Data Gathering
As climate change continues to impact the Region, it is vital that data be gathered to help the Region react appropriately to climate change impacts. Robust data collection practices will help the Region plan for future changes and will provide a basis for prioritizing and identifying high-priority projects that will provide adaptation or mitigation benefits. The general strategy for climate change data gathering is to align this specific data collection need with the overall data management process for the Region. As part of IRWM project implementation, different types of data will be collected to track project performance and meet monitoring program requirements. Table 13-6 provides detail on the types of data that may be collected during project implementation in order to support the Region’s efforts to adapt to and mitigate climate change.

Packet Pg. 712
2019 Westside-San Joaquin Integrated Regional Water
Management Plan Chapter 13 Climate Change
Final
January 2019 13-22
Table 13-6: Data Gathering Strategy to Assess Climate Change Impacts Climate Change
Vulnerability Category Potential Data to be Gathered
Water Demand  Water meter data (municipal, commercial, industrial)  Groundwater use (municipal and agricultural)
 Demand projections
 Population projections
Water Supply  Groundwater elevation data
 Streamflow (especially seasonal low flows)
 Reservoir levels
Water Quality  Groundwater quality (e.g., salinity, TDS, arsenic, nitrate)  Surface water quality (e.g., turbidity, temperature, dissolved oxygen)  Household water quality, particularly in DACs
Flood Management  Streamflow measurements
 Area flooded during storm events
 Value of assets in floodplain
Ecosystem and Habitat  Fish surveys
 Animal and plant surveys
 Habitat surveys (e.g., to assess streambed quality)
 Volume of water provided for environmental uses
Hydropower  Kilowatt hours produced
 Frequency of power generation
Packet Pg. 713
City of Patterson (0013240.00) Woodard & Curran, Inc.
2025 Urban Water Management Plan June 2026
APPENDIX E: CITY OF PATTERSON WATER SHORTAGE CONTINGENCY PLAN 2025.

Packet Pg. 714
DRAFT
City of
Patterson
Water
Shortage
Contingency
Plan 2025
June 2026
woodardcurran.com
95 Third Street | 2
nd Floor
San Francisco, California 94103
800.426.4262
Packet Pg. 715
City of Patterson (0013240.00) i Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

TABLE OF CONTENTS

1. INTRODUCTION..............................................................................................................................1-1

2. WATER SUPPLY RELIABILITY ANALYSIS.......................................................................................2-2

2.1 Water Service Reliability Findings.............................................................................................................2-2

2.2 Seismic Risk Assessment and Mitigation Plan.................................................................................. 2-10

3. ANNUAL WATER SUPPLY AND DEMAND ASSESSMENT PROCEDURES ................................. 3-11

4. WATER SHORTAGE STAGES........................................................................................................ 4-13

5. SHORTAGE RESPONSE ACTIONS................................................................................................ 5-16

5.1 Supply Augmentation Actions ................................................................................................................ 5-16

5.2 Demand Reduction Actions ..................................................................................................................... 5-17

5.3 Operational Changes.................................................................................................................................. 5-19

5.4 Additional Mandatory Restrictions ....................................................................................................... 5-20

6. COMMUNICATION PROTOCOLS ................................................................................................ 6-21

7. COMPLIANCE AND ENFORCEMENT........................................................................................... 7-22

8. LEGAL AUTHORITIES ................................................................................................................... 8-23

9. FINANCIAL CONSEQUENCES OF WSCP ..................................................................................... 9-24

10. MONITORING AND REPORTING .............................................................................................. 10-25

11. WSCP REFINEMENT PROCEDURE............................................................................................. 11-26

12. SPECIAL WATER FEATURE DISTINCTION ................................................................................ 12-27

13. PLAN ADOPTION, SUBMITTAL, AND AVAILABILITY.............................................................. 13-28 Packet Pg. 716
City of Patterson (0013240.00) ii Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
TABLES
Table 2-1. Normal Year Supply and Demand Comparison (DWR Table 7-2) Table 2-2. Normal Year Supply and Demand Comparison (Potable Only) Table 2-3. Normal Year Supply and Demand Comparison (Non-Potable Only) Table 2-4. Single Dry Year Supply and Demand Comparison (DWR Table 7-3) Table 2-5. Single Dry Year Supply and Demand Comparison (Potable Only) Table 2-6. Single Dry Year Supply and Demand Comparison (Non-Potable Only) Table 2-8. Multiple Dry Years Supply and Demand Comparison (DWR Table 7-4) Table 2-9. Multiple Dry Years Supply and Demand Comparison (Potable Only) Table 2-10. Multiple Dry Years Supply and Demand Comparison (Non-Potable Only) Table 2-10. Drought Risk Assessment (DWR Table 7-5)
Table 4-1: Water Shortage Contingency Plan Levels
Table 4-2: Cross-Reference for Standard vs. Supplier Shortage Levels (DWR Table 8-1) Table 5-1: Supply Augmentation and Other Actions (DWR Table 8-2) Table 5-2: Demand Reduction Actions (DWR Table 8-3)
Table 6-1: Communication Protocol for Each Water Shortage Level Table 7-1: WSCP Penalties and Charges

APPENDICES
Appendix A: Public Notices and Resolutions
Appendix B: Emergency Response Plan (ERP)
Packet Pg. 717
City of Patterson (0013240.00) iii Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

LIST OF ACRONYMS AND ABBREVIATIONS
Acronym Definition
AF Acre-Feet
AFY Acre-Feet per Year
AMI Advanced Metering Infrastructure
CIMIS
California Irrigation Management Information
System
City City of Patterson
CVP Central Valley Project
CWC California Water Code
DOF California Department of Finance
DRA Drought Risk Assessment
DWR California Department of Water Resources
ERP Emergency Response Plan
gpcd Gallons per Capita per Day
GSP Groundwater Sustainability Plan
MCL Maximum Contaminant Level
PRP Pumping Reduction Plan
Subbasin Delta-Mendota Subbasin
SWRCB State Water Resources Control Board
THM Total Trihalomethanes
UWMP Urban Water Management Plan
UWUO Urban Water Use Objective
WSCP Water Shortage Contingency Plan
Packet Pg. 718
City of Patterson (0013240.00) 1-1 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

1. INTRODUCTION
The City of Patterson (City) Water Shortage Contingency Plan (WSCP) is a detailed operational plan that documents how the City will respond to a variety of water shortage scenarios. The WSCP establishes protocols for triggering City-wide water supply shortage levels, implementing corresponding water shortage response actions to respond to actual supply conditions, and ensures the strategic management of a short- or long-term water shortage event.

A water shortage may occur due to a variety of potential scenarios, such as drought, climate change, regulatory constraints, natural or human caused disasters, and catastrophic events which may occur at any time. The WSCP is the City’s operating manual that allows the City Council, staff, and the public to identify and efficiently implement pre-determined steps to manage a water shortage.

To match the Urban Water Management Plan (UWMP), the City reports water volumes in units of acre-feet (AF) and acre-feet per year (AFY) in the WSCP.

Packet Pg. 719
City of Patterson (0013240.00) 2-2 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

2. WATER SUPPLY RELIABILITY ANALYSIS
California Water Code (CWC) Section 10632(a)(1) requires an analysis of water supply reliability per CWC Section 10635. The City relies exclusively on groundwater to meet customer needs and has historically met customer demands through times of drought. Conditions could arise such as catastrophic events, prolonged periods of drought, unforeseen impacts to the groundwater supply, etc. that could require the activation of the WSCP.

2.1 Water Service Reliability Findings
The City maintains seven (7) potable well facilities and associated water storage tanks, and three (3) nonpotable irrigation-only well facilities to meet the maximum day demand and fire protection requirements of its water system with the largest well source offline, in accordance with State of California Code of Regulations, Title 22 California Waterworks Standards. All water is pumped from the Delta-Mendota Subbasin.

The rest of this subsection summarizes at a high level the assumptions and results of the water service reliability analysis conducted as part of Chapter 7 of the 2025 UWMP.

Assumptions by water supply source:
• Groundwater, Lower Aquifer: 2,626 AFY for 2030 and beyond in all year types, based on pumping limitations set by the Northern Delta‑Mendota Region Pumping Reduction Plan (PRP) • Groundwater, Upper Aquifer: Approximately 2,000 AFY for potable uses, and 677 AFY for nonpotable uses, in all year types. • Del Puerto Creek Recharge and Recovery project:
o Normal Year:
▪ Stormwater: 750 AFY
▪ Surface water: 800 AFY
o Single dry year:
▪ Stormwater: 491 AF – Based on precipitation data collected at the Patterson CIMIS Station for Water Years 2000-2017, precipitation in dry and critically dry years (San Joaquin water year index) is 65% of average year precipitation of 12.2 inches per year. Thus, the 750 AF of average year supply available from stormwater is assumed to be 750 * 65% = 491 AF.
▪ Surface water: 800 AF; single-dry years are assumed to result in no reduction of available supply from Del Puerto Canyon Reservoir.
o Five consecutive dry years:

Packet Pg. 720
City of Patterson (0013240.00) 2-3 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
▪ Stormwater: 491 AF – same assumption as a single-dry year; during the 2012-2016 multi-year drought, precipitation was variable but was similar to the overall average of dry and critically dry years.
▪ Surface water: the first year of a 5 consecutive dry year cycle is assumed to provide the full assumption of 800 AF of surface water supply. In subsequent years, the City assumes water will be available from Del Puerto Canyon Reservoir, but at a reduced rate similar to reductions in allocations made for South of Delta urban contractors from the Central Valley Project during the 2012-2016 drought (70% of supply allocation in 2013 as year 2, 50% in 2014 as year 3, 25% in 2015 as year 4, and 55% in 2016 as year 5).
• Surface water expansion project
o Normal Year: Up to 6,000 AFY
o Single dry year: No reduction
o Five consecutive dry years: same percent reductions as was described for surface water in the Del Puerto Creek Recharge and Recovery project.
• As-needed purchase of additional surface water to supplemental non-potable uses:
o All year types: as-needed basis to meet non-potable demands, as described in UWMP The following DWR reporting tables depict the City’s water reliability assessment showing water demands and water supply availability for various water supply scenarios.

Table 2-1 depicts normal year supply and demand conditions through 2050 indicating the City has adequate supplies to meet future water needs during normal year conditions. Table 2-2 shows the same comparison for potable only, while Table 2-3 shows only non-potable supplies and demands.

TABLE 2-1. NORMAL YEAR SUPPLY AND DEMAND COMPARISON (DWR TABLE 7-2) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
Supply totals 4,909 5,364 5,937 11,391 11,410
Use totals 4,804 5,364 5,937 6,516 6,648
Surplus/(shortfall) 105 0 0 4,875 4,762
Note – Required DWR Table 7-2 combines both supply and demands for potable and non-potable supplies which must be considered separately for the City of Patterson. See the following two tables for a breakdown of Potable and Non-Potable scenarios.

TABLE 2-2. NORMAL YEAR SUPPLY AND DEMAND COMPARISON (POTABLE ONLY) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
Supply totals 4,176 4,471 4,883 10,176 10,176
Use totals 4,071 4,471 4,883 5,301 5,414
Surplus/(shortfall) 105 0 0 4,875 4,762
Packet Pg. 721
City of Patterson (0013240.00) 2-4 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
TABLE 2-3. NORMAL YEAR SUPPLY AND DEMAND COMPARISON (NON-POTABLE ONLY) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
Supply totals 733 893 1,054 1,215 1,234
Use totals 733 893 1,054 1,215 1,234
Surplus/(shortfall) 0 0 0 0 0
Table 2-4 depicts single dry year supply and demand conditions through 2050. Table 2-5 shows the same table for potable supplies and demands only, with Table 2-6 only including non-potable supplies and demands.

TABLE 2-4. SINGLE DRY YEAR SUPPLY AND DEMAND COMPARISON (DWR TABLE 7-3) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
Supply totals 4,647 5,102 5,675 11,129 11,148
Use totals 4,804 5,364 5,937 6,516 6,648
Surplus/(shortfall) (158) (263) (263) 4,613 4,500
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit 158 263 263
WSCP - use reduction savings benefit
Revised Surplus/(shortfall) 0 0 0
Note – Required DWR Table 7-3 combines both supply and demands for potable and non-potable supplies which must be considered separately for the City of Patterson. See the following two tables for a breakdown of Potable and Non-Potable scenarios.

TABLE 2-5. SINGLE DRY YEAR SUPPLY AND DEMAND COMPARISON (POTABLE ONLY) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
Supply totals 3,914 4,209 4,621 9,914 9,914
Use totals 4,071 4,471 4,883 5,301 5,414
Surplus/(shortfall) (158) (263) (263) 4,613 4,500
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit 158 263 263
WSCP - use reduction savings benefit
Revised Surplus/(shortfall) 0 0 0
Packet Pg. 722
City of Patterson (0013240.00) 2-5 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
TABLE 2-6. SINGLE DRY YEAR SUPPLY AND DEMAND COMPARISON (NON-POTABLE ONLY) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
Supply totals 733 893 1,054 1,215 1,234
Use totals 733 893 1,054 1,215 1,234
Surplus/(shortfall) 0 0 0 0 0
Table 2-7 depicts supply and demand conditions through 2050 for a multiple dry year scenario (five consecutive dry years), similar to the 2012-2016 drought cycle. Table 2-8 shows the same table with potable supplies and demands only, while Table 2-9 shows only non-potable supplies and demands.

Packet Pg. 723
City of Patterson (0013240.00) 2-6 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
TABLE 2-7. MULTIPLE DRY YEARS SUPPLY AND DEMAND COMPARISON (DWR TABLE 7-4) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
First year
Supply totals 4,647 5,102 5,675 9,029 11,148
Use totals 4,804 5,364 5,937 6,516 6,648
Surplus/(shortfall) (158) (263) (263) 2,513 4,500
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit 158 263 263
WSCP - use reduction savings benefit
Revised Surplus/(shortfall) 0 0 0 4,613 4,500
Second
year
Supply totals 4,407 4,862 5,435 9,089 9,108
Use totals 4,804 5,364 5,937 6,516 6,648
Surplus/(shortfall) (398) (503) (503) 2,573 2,460
OPTIONAL WSCP Actions
WSCP - supply augmentation benefit 0 55 14
WSCP - use reduction savings benefit 407 447 488
Revised Surplus/(shortfall) 10 0 0 2,573 2,460
Third
year
Supply totals 4,247 4,702 5,275 7,729 7,748
Use totals 4,804 5,364 5,937 6,516 6,648
Surplus/(shortfall) (558) (663) (663) 1,213 1,100
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit 150 215 174
WSCP - use reduction savings benefit 407 447 488
Revised Surplus/(shortfall) 0 0 0 1,213 1,100
Fourth
year
Supply totals 4,047 4,502 5,075 6,029 6,048
Use totals 4,804 5,364 5,937 6,516 6,648
Surplus/(shortfall) (758) (863) (863) (488) (601)
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit 814 894 977 1,060 1,083 Revised Surplus/(shortfall) 57 32 114 573 482
Fifth year
Supply totals 4,287 4,742 5,315 8,069 10,788
Use totals 4,804 5,364 5,937 6,516 6,648
Surplus/(shortfall) (518) (623) (623) 1,553 4,140
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit 611 671 732
Revised Surplus/(shortfall) 93 48 110 1,553 4,140
Note – Required DWR Table 7-4 combines both supply and demands for potable and non-potable supplies which must be considered separately for the City of Patterson. See the following two tables for a breakdown of Potable and Non-Potable scenarios.

Packet Pg. 724
City of Patterson (0013240.00) 2-7 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
TABLE 2-8. MULTIPLE DRY YEARS SUPPLY AND DEMAND COMPARISON (POTABLE ONLY) 2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 (AF)
First
year
Supply totals 3,914 4,209 4,621 9,914 9,914
Use totals 4,071 4,471 4,883 5,301 5,414
Surplus/(shortfall) (158) (263) (263) 4,613 4,500
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit 158 263 263
WSCP - use reduction savings benefit
Revised Surplus/(shortfall) 0 0 0
Second
year
Supply totals 3,674 3,969 4,381 7,874 7,874
Use totals 4,071 4,471 4,883 5,301 5,414
Surplus/(shortfall) (398) (503) (503) 2,573 2,460
OPTIONAL WSCP Actions
WSCP - supply augmentation benefit 0 55 14
WSCP - use reduction savings benefit 407 447 488
Revised Surplus/(shortfall) 10 0 0
Third
year
Supply totals 3,514 3,809 4,221 6,514 6,514
Use totals 4,071 4,471 4,883 5,301 5,414
Surplus/(shortfall) (558) (663) (663) 1,213 1,100
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit 150 215 174
WSCP - use reduction savings benefit 407 447 488
Revised Surplus/(shortfall) 0 0 0
Fourth
year
Supply totals 3,314 3,609 4,021 4,814 4,814
Use totals 4,071 4,471 4,883 5,301 5,414
Surplus/(shortfall) (758) (863) (863) (488) (601)
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit 814 894 977 1,060 1,083 Revised Surplus/(shortfall) 57 32 114 573 482
Fifth
year
Supply totals 3,554 3,849 4,261 6,854 9,554
Use totals 4,071 4,471 4,883 5,301 5,414
Surplus/(shortfall) (518) (623) (623) 1,553 4,140
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit 611 671 732
Revised Surplus/(shortfall) 93 48 110
Packet Pg. 725
City of Patterson (0013240.00) 2-8 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
TABLE 2-9. MULTIPLE DRY YEARS SUPPLY AND DEMAND COMPARISON (NON-POTABLE ONLY) 2030
(AF)
2035
(AF)
2040
(AF)
2045
(AF)
2050
(AF)
First
year
Supply totals 733 893 1,054 1,215 1,234
Use totals 733 893 1,054 1,215 1,234
Surplus/(shortfall) 0 0 0 0 0
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit
Revised Surplus/(shortfall)
Second
year
Supply totals 733 893 1,054 1,215 1,234
Use totals 733 893 1,054 1,215 1,234
Surplus/(shortfall) 0 0 0 0 0
OPTIONAL WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit
Revised Surplus/(shortfall)
Third
year
Supply totals 733 893 1,054 1,215 1,234
Use totals 733 893 1,054 1,215 1,234
Surplus/(shortfall) 0 0 0 0 0
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit
Revised Surplus/(shortfall)
Fourth
year
Supply totals 733 893 1,054 1,215 1,234
Use totals 733 893 1,054 1,215 1,234
Surplus/(shortfall) 0 0 0 0 0
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit
Revised Surplus/(shortfall)
Fifth
year
Supply totals 733 893 1,054 1,215 1,234
Use totals 733 893 1,054 1,215 1,234
Surplus/(shortfall) 0 0 0 0 0
OPTIONAL Planned WSCP Actions
WSCP - supply augmentation benefit
WSCP - use reduction savings benefit
Revised Surplus/(shortfall)
The Drought Risk Assessment (DRA) is an evaluation of local water supply availability, assuming the next five years (2026-2030) are hydrologically equivalent to the driest five consecutive years on record. The assumptions are summarized below, with more detail in Section 7 of the 2025 UWMP:

Packet Pg. 726
City of Patterson (0013240.00) 2-9 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
• Unconstrained demands for 2026-2029 were linearly interpolated between 2025 actuals and 2030 projected demands for the “existing” service area without Zacharias Baldwin development.

Demands for the Zacharias Baldwin development are assumed to first come online in 2029, before reaching the 2030 projected value, meaning 0 AFY of demands 2026-2028. • Groundwater supply, Lower Aquifer: Pumping reductions scale from 92 AFY in 2025 to 460 AFY in 2030. The model-estimated baseline pumping from the Lower Aquifer from Water Years 2019-2023 is 3,086 AFY. Thus the 2025 available Lower Aquifer supply is assumed to be 2,994 AF and 2030 available supply is 2,626 AF, with 2026-2029 linearly interpolated between those values. • Groundwater supply, Upper Aquifer: Shown to be equal to non-potable demands, as the City expects enough non-potable supplies to be available to meet these demands in any year type. The City also anticipates transitioning some Upper Aquifer supplies from serving non-potable demands to serving potable demands (after treatment is added) sometime over the next 5-10 years.

Table 2-10 contains the results of the drought risk assessment.

TABLE 2-10. DROUGHT RISK ASSESSMENT (DWR TABLE 7-5)
2026 Total Potable Non-Potable
Total Water Use (AF) 4,215 3,678 537
Total Supplies (AF) 3,457 2,920 537
Surplus/Shortfall w/o WSCP Action (757) (757) 0
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation) WSCP - supply augmentation benefit (AF)
WSCP - use reduction savings benefit (AF) 757 757
Revised Surplus/(shortfall) 0 0
2027 Total Potable Non-Potable
Total Water Use (AF) 4,284 3,698 586
Total Supplies (AF) 4,284 3,698 586
Surplus/Shortfall w/o WSCP Action 0 0 0
2028 Total Potable Non-Potable
Total Water Use (AF) 4,352 3,717 635
Total Supplies (AF) 4,352 3,717 635
Surplus/Shortfall w/o WSCP Action 0 0 0
2029 Total Potable Non-Potable
Total Water Use (AF) 4,578 3,894 684
Total Supplies (AF) 4,579 3,895 684
Surplus/Shortfall w/o WSCP Action 0 0 0
2030 Total Potable Non-Potable
Total Water Use (AF) 4,804 4,071 733
Total Supplies (AF) 4,804 4,071 733
Surplus/Shortfall w/o WSCP Action 0 0 0
Packet Pg. 727
City of Patterson (0013240.00) 2-10 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

2.2 Seismic Risk Assessment and Mitigation Plan
The CWC requires the City’s WSCP to include a seismic risk assessment and mitigation plan to assess the vulnerability of each water facility. Per CWC Section 10632.5 (c), this requirement is met by the Stanislaus 2022 Multi-Jurisdictional County Hazard Mitigation Plan which includes hazard vulnerability assessments and mitigation plans (including for earthquakes). This plan is available to the public through the Stanislaus County Office of Emergency Services website (oes.stancounty.gov). There are several major faults in the region that could generate a seismic event that could impact City water facilities including the Great Valley Thrust Fault System, Ortigalita Fault Zone, and the San Joaquin Fault. The City closely monitors its water facilities and is prepared to rehabilitate infrastructure should an earthquake hazard impact its water system.

The City’s Emergency Response Plan (ERP) describes the City’s plan for responding to a variety of other catastrophic water shortage conditions, such as the impacts of a seismic event. A copy of the ERP can be found in Appendix B.

Packet Pg. 728
City of Patterson (0013240.00) 3-11 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

3. ANNUAL WATER SUPPLY AND DEMAND ASSESSMENT PROCEDURES CWC Section 10632 (a)(2) requires written procedures to be developed to conduct an annual water supply and demand assessment (annual assessment) to determine the water system’s reliability, assuming the upcoming year is a dry year. The annual assessment and accompanying shortage report must be completed and submitted to the California Department of Water Resources (DWR) by July 1 of each year. For these annual assessments and shortage reports, the “year” refers to the 12-month period beginning July 1 and ending the following June 30 per DWR guidelines.

The documented steps to complete the annual assessment are described below, as well as the decisionmaking process for declaring a shortage.

Available Water Supply
As previously described, the City relies exclusively on groundwater supplies. Available water supplies for the City shall be quantified each year by summing the capacity of each operational groundwater well, typically assuming that one well is offline. The resulting well capacity will be compared to the available groundwater supply that can be pumped under any limitations imposed by the Pumping Reduction Plan that the City participates in as a management action from the Delta-Mendota Subbasin Groundwater Sustainability Plan (GSP). Typically, the lower of the two values is used as an estimated available supply for the coming year.

Unconstrained Customer Demand
Water use for the previous year of available data at the time the analysis is conducted shall be quantified by summing the billed water usage for all customers by user class for the previous year. Customer water demands for the City shall be projected for the upcoming year based on the previous year’s water usage and anticipated new customer connections and per capita target assumptions. If a water shortage was active during the previous year, demands will be increased by the estimated percent reduction requested or otherwise imposed during the active water shortage period.

The first step to calculate the anticipated additional new demand is to calculate the future population changes. To calculate future population, the number of anticipated new customer connections shall be multiplied by the number of persons per household as indicated on updated Department of Finance (DOF) data tables shown on the DOF website for the City. That number shall then be added to the current population to obtain the future population.

𝐹𝑢𝑡𝑢𝑟𝑒 𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 = 𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 + (𝑁𝑜. 𝑜𝑓 𝑁𝑒𝑤 𝐶𝑜𝑛𝑛𝑒𝑐𝑡𝑖𝑜𝑛𝑠 × 𝑃𝑒𝑟𝑠𝑜𝑛𝑠 𝑝𝑒𝑟 𝐻𝑜𝑢𝑠𝑒ℎ𝑜𝑙𝑑) To calculate anticipated demands for the upcoming year, each meter usage per customer class shall be multiplied by the future population and then divided by the current population.

𝐴𝑛𝑡𝑖𝑐𝑖𝑝𝑎𝑡𝑒𝑑 𝐷𝑒𝑚𝑎𝑛𝑑 =
𝑀𝑒𝑡𝑒𝑟 𝑈𝑠𝑎𝑔𝑒 × 𝐹𝑢𝑡𝑢𝑟𝑒 𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛
𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛
Evaluation Criteria
If the available water supply is greater than the anticipated customer demand for the upcoming year, then the City would not need to take any further action. If the anticipated customer demands for the upcoming Packet Pg. 729
City of Patterson (0013240.00) 3-12 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
year are greater than the available water supplies, the City will initiate appropriate water shortage response actions as detailed in this WSCP.

Infrastructure Considerations
If infrastructure projects are anticipated for the upcoming year that could impact water supply production (e.g. repairs and/or replacement of existing wells, development of new groundwater well, etc.), these water supply impacts shall be evaluated for the timeframe (i.e. months) when the infrastructure projects will impact the available water system capacity. Thus, the available water supply shall be increased or reduced accordingly for each month based on expected months of well non-availability and/or when new or replacements supplies are developed and brought online providing additional system capacity.

Decision-Making Process
If a shortage is predicted for the coming year, the shortage report will be presented to the City Council following the completion of the annual assessment. The City Council shall review and approve the findings of the annual assessment and if necessary, trigger implementation of any water shortage response actions resulting from the annual assessment findings through a resolution.

Packet Pg. 730
City of Patterson (0013240.00) 4-13 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

4. WATER SHORTAGE STAGES
CWC Section 10632 (a)(3)(A) requires standard water shortage levels including greater than a 50-percent reduction in water supply conditions. The City follows the standard six water shortage levels, also known as stages, suggested by DWR’s 2025 Urban Water Management Plan Guidebook. The City will implement these water shortage levels in response to corresponding water supply shortages to comply with CWC requirements. The stages will be implemented during water supply shortages, due to City water system constraints, or due to outside factors (e.g. State water use cutbacks or regional drought conditions that may not be directly influencing the City’s water supplies). The determination and declaration of a water supply shortage stage will be made by the City of Patterson City Council.

Stage 1
This level would be initiated during a mild water shortage (up to 10%) and is part of an ongoing public information campaign encouraging voluntary water conservation. The City could achieve up to a 10% reduction voluntarily or could issue a resolution triggering Stage 1 voluntary water use reductions up to 10%. There are no mandatory measures implemented during a Stage 1 response. Although Stage 1 is very achievable, customers would be reminded of regional dry year concerns and any short interruptions in water service when the City may have a redundant back-up well offline for repairs, which makes the overall supply system more vulnerable to shortages.

Stage 2
This level would be initiated during a moderate water shortage (11-20%) and would be addressed through enhanced voluntary measures and public outreach with voluntary enforcement of the water waste ordinance. Failure of one groundwater supply well could cause a moderate reduction in water supply, resulting in implementation of Stage 2 measures. Stage 2 would also be implemented during an on-going regional drought condition where water conservation is voluntary with little to no actual impact on the City’s groundwater supply capacity. During Stage 2 conditions, the City Council could declare certain water use prohibitions in accordance with the City’s water waste ordinance.

Stage 3
This level would be initiated during a more severe water shortage (21 to 30%), which could be caused by State-mandated water use reductions or a catastrophic failure of up to two City groundwater supply wells.

During a Stage 3 condition, the City Council would implement a combination of voluntary and mandatory measures as needed to meet the specific water shortage cutback target. The City Manager would have the authority to implement City Council directed water shortage response measures including the implementation of additional prohibitions and consumption reduction methods that could include cutbacks in irrigation water use by all customers, enhanced leak repair by utilities and customers, City establishment of water shortage pricing surcharges, and other consumption reduction methods as needed to effectively reduce water demands to match available supplies.

Stage 4
This level would be initiated during a critical water shortage (31 to 40%), which could be caused by a catastrophic failure of up to three groundwater supply wells. All actions taken in the prior stages would be intensified and production would be monitored daily for compliance with necessary water use reductions.

Packet Pg. 731
City of Patterson (0013240.00) 4-14 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
Customers would be under strict enforcement of no waste policies and water rationing would be considered.

The City may declare a water shortage emergency to immediately repair and bring well capacity back online in a timely manner.

Stage 5
This level would be initiated during a critical water shortage (41-50%), which could be caused by a natural disaster, prolonged severe drought event, or catastrophic failure of water system facilities that greatly reduces water supply capacity by more than 40% from normal operation capacities. Severe limitations would be placed on irrigation use by all customers, leaks would be required to be repaired within five days, and all non-essential City operations (e.g. flushing) would be curtailed until further notice.

Stage 6
This level would be initiated during a catastrophic water shortage (>50%), which could be caused by a natural disaster or catastrophic failure requiring severe and immediate cutbacks in customer water demands. Rationing and mandatory restrictions would be enhanced as needed to effectively reduce water demands to match available supplies. Indoor use may be capped on an account-level basis at the State mandated indoor residential urban water use objective on a gallons per capita per day (gpcd) basis.

Packet Pg. 732
City of Patterson (0013240.00) 4-15 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
Table 4-1 summarizes the City’s six (6) water shortage levels included in a compliant WSCP. As indicated in the following Table 4-2, these are the standard six levels of water shortage.

TABLE 4-1: WATER SHORTAGE CONTINGENCY PLAN LEVELS
Shortage
Level
Percent Shortage
Range
Numerical value
as a percent
Water Shortage Condition
(Narrative description)
1 Up to 10%
Mild Water Shortage - drought or loss of
redundant wellsupply.
2 Up to 20%
Moderate Water Shortage - drought or temporary loss
of one (1) well.
3 Up to 30%
Severe Water Shortage - drought, State cutbacks, or
permanent loss of one (1) well.
4 Up to 40%
Critical Water Shortage - extended drought, State
cutbacks, loss of two (2) wells.
5 Up to 50%
Critical Water Shortage - extended drought, State
cutbacks, loss of three (3) wells.
6 >50%
Catastrophic Water Shortage - natural disaster, major
system failures, energy supply disruptions.

NOTES: Cutbacksin water use will be based on triggered shortage level and percent reduction target based on normal year per capita water use levels.

TABLE 4-2: CROSS-REFERENCE FOR STANDARD VS. SUPPLIER SHORTAGE LEVELS (DWR TABLE 8-1) Check the box if the Supplier uses the Standard six
levels of water shortage.

Proceed to the next table.

Packet Pg. 733
City of Patterson (0013240.00) 5-16 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

5. SHORTAGE RESPONSE ACTIONS
In the case that a shortage is declared, the City would implement appropriate response actions to address anticipated supply and demand gaps. These response actions address the water shortage on multiple fronts and include supply augmentation, demand reduction, and operational changes. As water shortage severity increases, corresponding response measures become more mandatory and severe to ensure that percent shortage cutback targets are met during a given water shortage event. For example, the City would migrate from voluntary water use reduction methods utilized in stages 1 and 2, to more mandatory actions during a stages 3 and 4. Response actions can be added or modified as needed to achieve percent reduction targets with least impact on customers and the economy. The following sections summarize the City’s planned response actions.

5.1 Supply Augmentation Actions
The City has very few supply augmentation options especially for potable water supplies. Developing additional non-potable wells supplies or adding new recycled water options would take years to develop and would not be available during the short-term shortage condition at hand. The City might consider emergency exchanges, transfers, or purchases on an interim basis of water supplied from neighboring water agencies as feasible. These would be very expensive to the City and would likely be non-potable emergency supplies with limited uses in the City service area. The City could also attempt to increase pumping capacity from operational wells. Table 5-1 indicates some of the options available to the City to stretch existing supplies or augment under emergency conditions.

TABLE 5-1: SUPPLY AUGMENTATION AND OTHER ACTIONS (DWR TABLE 8-2) Yes Is the Supplier completing this table using the standard six levels? (yes/no) Shortage
Level
Supply Augmentation
Methods and Other Actions
by Water Supplier
How much is this going to
reduce the shortage gap? Additional Explanation or
Reference
Volume or (OPTIONAL)
Percentage
Shortage Gap
Reduction
Value
3 and 4
Implement or Modify
Drought Rate Structure or
Surcharge
Percentage up to 5%
(or 200 AF)
Cover additional costs associated
with water shortage response
actions
5 and 6 Other Actions Volume 912 AF Increase pumping from existing potable wells (12 hrs/day)
5 and 6 Other Actions Volume 2,129 AF Increase pumping from existing non-potable wells (24 hrs/day)
5 and 6 Exchanges Percentage up to 10%
(or 400 AF)
Bring in temporary non-potable
supplies
NOTES: The City has very few supply augmentation measures other than to increase pumping capacity from existing wells and attempt to secure short-term supplies from neighboring agencies, which would be very expensive to the City and likely only benefit non-potable uses.

Packet Pg. 734
City of Patterson (0013240.00) 5-17 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

5.2 Demand Reduction Actions
Because supply augmentation opportunities are extremely limited, the City’s water shortage response actions focus heavily on demand reduction. Table 5-2 lists the potential demand reduction measures the City would implement as additional WSCP stages are triggered by shortage conditions. As previously stated, these reduction actions may be modified as needed to achieve the necessary demand reduction targets while minimizing impact to customers.

TABLE 5-2: DEMAND REDUCTION ACTIONS (DWR TABLE 8-3)
Shortage
Level
Demand Reduction
Actions
How much is this going
to reduce the shortage
gap?
Additional Explanation or
Reference
(OPTIONAL)
Penalty,
Charge, or
Other
Enforcement?
Volume or
Percentage
Drop down
Shortage
Gap
Reduction
Value
(May be a
range)
1 to 2 Other Percentage 0 - 20% Voluntary Restrictions - No Waste No
1 to 2
Expand Public
Information
Campaign
Percentage 0 - 20%
General increase in public
outreach measures
including social media,
apps, and other means
No
1 to 2 Improve Customer
Billing Percentage up to 5%
Provide more real-time
water use data as
available through AMI
projects
No
1 to 2 Offer Water Use
Surveys Percentage up to 5% Especially to large water users No
1 to 3 Other Percentage 0 - 30% Voluntary Water Use
Reductions No
1 to 2
Provide Rebates on
Plumbing Fixtures
and Devices
Percentage up to 5% Enhance plumbing fixture
rebates No
1 to 3 Other Percentage 10 - 30% Expedite conversion of water efficient fixtures No
1 to 3
Landscape - Limit
landscape
irrigation to
specific days
Percentage 0 - 20% Limit irrigation to 3
watering days/week Yes
1 to 4 Landscape - Limit
landscape Percentage 0 - 40% Limit irrigation to 2 watering days/week Yes Packet Pg. 735
City of Patterson (0013240.00) 5-18 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
Shortage
Level
Demand Reduction
Actions
How much is this going
to reduce the shortage
gap?
Additional Explanation or
Reference
(OPTIONAL)
Penalty,
Charge, or
Other
Enforcement?
Volume or
Percentage
Drop down
Shortage
Gap
Reduction
Value
(May be a
range)
irrigation to
specific days
1 to 6
Other - Customers
must repair leaks,
breaks, and
malfunctions in a
timely manner
Percentage 10-50%+ Repair within 5 days of
detection No
2 to 6
Landscape -
Prohibit certain
types of landscape
irrigation
Percentage 20 - 50%+ Reduce parks/open space
irrigation No
3 and 4
Provide Rebates
for Landscape
Irrigation Efficiency
Percentage up to 5%
Provide or enhance
landscape rebates (e.g.
sprinkler rebates)
No
3 and 4 Decrease Line
Flushing Percentage up to 5%
Reducing line flushing
while still avoiding THM
MCL violations
No
3 and 4
Implement or
Modify Drought
Rate Structure or
Surcharge
Percentage up to 5%
Cover additional costs
associated with water
shortage response
activities, and encourage
additional conservation
Yes
3 to 6
Expand Public
Information
Campaign
Percentage 30 - 50%+ General and specific
public outreach measures No
3 to 6 Reduce System
Water Loss Percentage 20 - 50%+ Expedite larger utility leak repairs No 3 to 6 Increase Water
Waste Patrols Percentage 20 - 50%+
Mandatory restrictions -
no waste enforced via
patrols, tickets, fines, etc.

Yes
3 to 6
Implement or
Modify Drought
Rate Structure or
Surcharge
Percentage 20 - 50%+ Apply water shortage
pricing for surcharge Yes
3 to 6 Other Percentage 20 - 50%+ Apply penalties for
excessive water use Yes
Packet Pg. 736
City of Patterson (0013240.00) 5-19 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026
Shortage
Level
Demand Reduction
Actions
How much is this going
to reduce the shortage
gap?
Additional Explanation or
Reference
(OPTIONAL)
Penalty,
Charge, or
Other
Enforcement?
Volume or
Percentage
Drop down
Shortage
Gap
Reduction
Value
(May be a
range)
4 to 6 Other Percentage 30 - 50%+ Restrict water use for only priority uses Yes
5 and 6 Other Percentage Up to 1%
Increased security or
monitoring by City staff
of hydrants to avoid
unauthorized
consumption
No
5 and 6
Moratorium or Net
Zero Demand
Increase on New
Connections
Percentage Up to
10%
Discuss phasing
permitted development Yes
5 and 6
Landscape -
Prohibit certain
types of landscape
irrigation
Percentage Up to
10%
Significant irrigation
prohibitions Yes
5 to 6
Landscape -
Prohibit certain
types of landscape
irrigation
Percentage 40 - 50%+ No lawn watering Yes
5 to 6 Other Percentage 40 - 50%+ Apply flow restrictions to customers
Yes
5 to 6 Other Percentage 40 - 50%+
Mandatory water
rationing, per capita
allotment
Yes
Yes Is the Supplier completing this table using the standard six levels? (yes/no)

5.3 Operational Changes
During a triggered water supply shortage condition the City can implement operational changes such as reducing water system flushing and increasing hydrant security. Operational changes are included in Table 5-2 as appropriate.

Packet Pg. 737
City of Patterson (0013240.00) 5-20 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

5.4 Additional Mandatory Restrictions
The City could implement additional mandatory restrictions against specific water use practices that may be considered excessive during given water shortage conditions. If drought or water shortages warrant mandatory restrictions (considered for Stage 3), the City could implement further restrictions if warranted based on Stage 3 or Stage 4 conditions. Table 5-2 identifies mandatory restrictions that would be enforced during a water shortage.

Packet Pg. 738
City of Patterson (0013240.00) 6-21 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

6. COMMUNICATION PROTOCOLS
The CWC Section 10632 (a)(5)(A) requires the City to notify all customers and interested parties of any anticipated water shortages as result of the annual water supply and demand assessment process. Per, the CWC Section 10632 (a)(5)(B), the City will also notify all customers and interested parties if any shortage response actions are triggered pursuant to the annual water supply and demand assessment results. In the event of an anticipated water shortage, the City will inform customers through newsletters and messages on the City website, water bill inserts, direct mail (e.g. post cards), newspapers, press releases, advertising, social media (NextDoor App), mobile electronic street signs, community workshops and meetings, and other communications as needed to meet water shortage reduction targets.

Communication protocols are summarized below in Table 6-1.

TABLE 6-1: COMMUNICATION PROTOCOL FOR EACH WATER SHORTAGE LEVEL Standard Shortage
Level
Standard Shortage
Levels
Typical Response
Action Type
Percent
Shortage Range
Communication Method
1 Voluntary Up to 10% Website
2 Enhanced Voluntary Up to 20% Stage 1 methods, plus:

Bill Insert, Newsletter
3 Voluntary/Mandatory Up to 30%
Stage 1 & 2 methods, plus:

Direct Mail, Newspaper, Press
Release, Advertising, Social Media,
Mobile Electronic Street Sign
4 Voluntary/Mandatory Up to 40%
Stage 1-3 methods, plus:

Community Workshop and
Meetings
5 Restrictions/Allocations Up to 50%
Stage 1-4 methods, plus:

Targeted Restriction and Allocation
Communications
6 Restrictions/Allocations > 50%
Stage 1-5 methods, plus:

Enhanced Targeted Restriction and
Allocation Communications
Packet Pg. 739
City of Patterson (0013240.00) 7-22 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

7. COMPLIANCE AND ENFORCEMENT
CWC Section 10632 (a)(6) requires an urban water supplier to penalize or charge for excessive use, where applicable. In accordance with the City Municipal Code (through adoption of the 2025 WSCP), when a water shortage emergency is declared, the City Manager may issue a Notice of Violation to any customer that fails to comply with the conditions of the ordinance. After one notice has been issued, further violations shall be punishable by a fine of: $25 for a first violation; $50 for a second violation; and $100 for a third violation; and thereafter the City may exercise the option of terminating water service for flagrant water waste compliance and enforcement situations.

Furthermore, each day upon which any condition of the ordinance is violated constitutes a separate violation. The City will ensure compliance and enforce provisions through water use field patrols, calls received at City offices, and/or communications received through social media supported by the City. The City will maintain records of all enforcement actions. The City Municipal Code will maintain updated policies and procedures related to implementation of the City’s updated WSCP.

During severe and critical water shortages (Stages 3-6), there may be additional penalties or charges applied for excessive water use. During these triggered water shortage conditions, the City Manager may take further actions if violations continue after the initial written warning, such as installing a flow-restricting device on the service line or termination of service for repeated violations of unauthorized water use. Table 7-1 summarizes when penalties and charges may take effect.

TABLE 7-1: WSCP PENALTIES AND CHARGES
Penalty or Charge Stage When Penalty or Charge Takes Effect Penalty for excess use 3-6
Charge for excess use 3-6
Flow Restriction 5-6
Termination of Service 5-6
In accordance with the City’s Municipal Code (Section 13.24.240), violations or fines may be appealed for reconsideration. Appeals for reconsideration shall be processed as indicated in the City Municipal Code provisions.

Packet Pg. 740
City of Patterson (0013240.00) 8-23 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

8. LEGAL AUTHORITIES
The City is a general law city with authorities to govern City business and services and enter into agreements or arrangements beneficial to the City in accordance with State laws and regulations. Per the City Municipal Code, the City has the authority to implement the water response actions presented herein and as necessary to meet the public health and safety needs of the community. The City has water code provisions in place to address water supply shortage and water waste conditions.

The City shall approve a DWR compliant WSCP by July 7, 2026 and may declare a water shortage emergency as required depending on the severity of the water shortage level/stage in accordance with CWC Chapter 3, Sections 350 through 359. This includes provisions related to penalties and charges associated with WSCP implementation actions.

The City shall coordinate with Stanislaus County for the possible proclamation of a local water supply emergency per California Government Code, California Emergency Services Act, Article 2, Section 8558.

Packet Pg. 741
City of Patterson (0013240.00) 9-24 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

9. FINANCIAL CONSEQUENCES OF WSCP
CWC Section 10632 (a)(8) requires a description of the impacts of consumption reduction on the revenues and expenditures of the urban water supplier. The City has established an accounting system for tracking expenses and revenue shortfalls associated with voluntary and mandatory water use reductions implemented through WSCP water shortage response actions. The City maintains reserve funds that can be used to offset expenditure impacts during times of emergency. Further, the City would implement a water surcharge upon triggering of a Stage 3 (or higher) WSCP declaration to recover unmitigated revenue shortfalls resulting from the costs of additional water shortage response actions. The water surcharge would only be in effect during the declared water shortage condition. Any water-related surcharges would be approved by the City Council, validating the need for the surcharges and identifying appropriate costs to be covered through any approved surcharges to support WSCP implementation.

Packet Pg. 742
City of Patterson (0013240.00) 10-25 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

10. MONITORING AND REPORTING
Per CWC Section 10632 (a)(9), the City will monitor and report on the implementation of its WSCP. Monthly metered water production and consumption data will be collected, tracked, and analyzed to monitor compliance and meet SWRCB water conservation reporting requirements. This water use reporting process will assist the State to determine compliance with per capita water use targets, established end use targets, and future cutback policy response during prolonged drought conditions.

As of June 2024, the City completed deployment of an Advanced Metering Infrastructure (AMI) system which collects hourly read data and provides real-time leak detection information for customers. Compared to pre-AMI meter reading, the additional AMI meter data provides the City with a real-time tracking tool to monitor customer water use and reductions levels during a triggered water shortage condition. The City has also made real-time water use information available to customers through an online EyeOnWater portal.

Packet Pg. 743
City of Patterson (0013240.00) 11-26 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

11. WSCP REFINEMENT PROCEDURE
Per CWC Section 10632 (a) (10), the City may choose to refine the WSCP based on monitoring and reporting of data collected. The City’s WSCP can be refined or updated at any time, independent of when UWMPs are updated every five years. Based on analysis of the data collected, the City may choose to modify or add consumption reduction methods to more accurately meet water level targets. Any updates to the WSCP will be approved by the City Council as needed to maintain an effective water shortage response plan for the community.

Any WSCP updates will allow for interested party review and be publicly noticed before any City Council action is considered at a planned City Council meeting. The WSCP documents and any updated information will be available on the City’s website.

Packet Pg. 744
City of Patterson (0013240.00) 12-27 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

12. SPECIAL WATER FEATURE DISTINCTION
The City does not have any special water features of distinction that are artificially supplied with water and would be involved in a WSCP response effort.

Packet Pg. 745
City of Patterson (0013240.00) 13-28 Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026

13. PLAN ADOPTION, SUBMITTAL, AND AVAILABILITY
The City conducted a public hearing to review its 2025 UWMP and WSCP at the June 16, 2026 City Council Meeting. Public notices were posted at least 7 and 14 days prior in the Patterson irrigator newspaper. The City’s 2025 UWMP and WSCP documents were available for review prior to the City Council meeting on the City’s website. The final 2025 UWMP and WSCP were adopted at the City Council Meeting on July 7, 2026.

The resolution and related public noticing can be found in Appendix A. The City’s adopted 2025 UWMP and WSCP were submitted to DWR through DWR’s online data portal and provided to the California State Library. The City’s 2025 UWMP and WSCP were also made available to interested parties involved in the plan development process including the County and agencies listed in Chapter 10 of the 2025 UWMP. The City’s adopted Final 2025 UWMP and WSCP are available for viewing or download from the City’s website.

Per the CWC, the following steps shall be performed prior to adoption of the WSCP. • Prior to adoption, the City will issue a notification of a public hearing to customers, the county, and other interested parties.
• The City will publish a public notice in a local newspaper for two consecutive weeks prior to the public hearing.
• The City shall hold a public hearing to obtain public input. • Following the public hearing or at a subsequent City Council meeting, the City Council shall formally adopt the WSCP.
• Per CWC Section 10632 (a)(c), the City will make the WSCP available on the City’s website, https://www.pattersonca.gov/669/Urban-Water-Management-Plan, within 30 days of adoption by the City Council.

The City may choose to amend its 2025 WSCP at any time on an as needed basis which will follow the steps listed above independent of future City UWMP updates.

Packet Pg. 746
City of Patterson (0013240.00) Woodard & Curran, Inc.
2025 Water Shortage Contingency Plan June 2026
APPENDIX A: PUBLIC NOTICES AND RESOLUTIONS
Packet Pg. 747

DEPARTMENT OF PUBLIC WORKS
e
s b.

April 8, 2026DATE:

SUBJECT:

Sincerely,
Department of Public Works
7laza
Cc: Aracely Alegre, City Clerk
TO:

FROM:

Existing state law requires each urban water supplier to prepare and adopt an urban water management plan at least once every five years. The City of Patterson (City) is currently preparing an update to its 2020 Urban Water Management Plan (UWMP) and Water Shortage Contingency Plan (WSCP). Together, the UWMP and WSCP document the City’s plans to ensure adequate water supplies to meet existing and future demands for water under a range of water supply conditions, including water shortages.

Maria Encinas, CFM
Water Resources Program Manager
Notice of Plan Preparation for 2025 Urban Water Management Plan & 2025 Water Shortage Contingency Plan Update
As part of the UWMP process, the City is required to notify those agencies which the City receives water from, sells water to, or the County in which water is delivered (California Water Code § 10621 (b)).

Additionally, the City is notifying those agencies listed in the Northern Delta-Mendota Region Management Committee. If you receive this letter, the City is either required to notify you or has chosen to do so voluntarily.

We anticipate having draft documents available for public review beginning May 13, 2026, with a public hearing anticipated for June 16, 2026 at a regularly scheduled City Council meeting. Once available, materials available for review will be posted to the City’s website at www.pattersonca.gov.

The final documents will be submitted to the California Department of Water Resources by July 1, 2026.

If you have any questions, please contact me at (209) 895-8061 or [email protected].

All Interested Parties
Maria Encinas, Water Resources Program Manager
William Barrera
Deputy Director - Operations & Maintenance
Sonia Delgado, QSP, CESSWI
Deputy Director - Regulatory Compliance & Administrative Services City Hall: 1 Plaza, Patterson, CA 95363 • Phone: (209) 895-8060 Corporation Yard: 16215 Baldwin Road, Patterson, CA 95363 • Phone: (209) 895-8160 Water Quality Control Facility: 14901 Poplar Avenue, Patterson, CA 95363 • Phone: (209) 895-8150 Main Email Address: [email protected]
Xavier Guluarte
Interim Director of Public Works
Packet Pg. 748
Packet Pg. 749
City of Patterson (0013240.00) Woodard & Curran, Inc.
2025 Water Shortage Contingency Plan June 2026
APPENDIX B: EMERGENCY RESPONSE PLAN (ERP)
Packet Pg. 750
Packet Pg. 751
Packet Pg. 752
Packet Pg. 753
Packet Pg. 754
Packet Pg. 755
Packet Pg. 756
Packet Pg. 757
Packet Pg. 758
Packet Pg. 759
Packet Pg. 760
Packet Pg. 761
Packet Pg. 762
Packet Pg. 763
Packet Pg. 764
Packet Pg. 765
Packet Pg. 766
Packet Pg. 767
Packet Pg. 768
Packet Pg. 769
Packet Pg. 770
Packet Pg. 771
Packet Pg. 772
Packet Pg. 773
Packet Pg. 774
Packet Pg. 775
Packet Pg. 776
Packet Pg. 777
Packet Pg. 778
Packet Pg. 779
Packet Pg. 780
Packet Pg. 781
Packet Pg. 782
Packet Pg. 783
Packet Pg. 784
Packet Pg. 785
Packet Pg. 786
Packet Pg. 787
Packet Pg. 788
Packet Pg. 789
Packet Pg. 790
Packet Pg. 791
Packet Pg. 792
Packet Pg. 793
Packet Pg. 794
Packet Pg. 795
Packet Pg. 796
Packet Pg. 797
Packet Pg. 798
Packet Pg. 799
Packet Pg. 800
Packet Pg. 801
Packet Pg. 802
Packet Pg. 803
Packet Pg. 804
Packet Pg. 805
Packet Pg. 806
Packet Pg. 807
Packet Pg. 808
Packet Pg. 809
Packet Pg. 810
Packet Pg. 811
Packet Pg. 812
Packet Pg. 813
Packet Pg. 814
Packet Pg. 815
Packet Pg. 816
Packet Pg. 817
Packet Pg. 818
Packet Pg. 819
Packet Pg. 820
Packet Pg. 821
Packet Pg. 822
Packet Pg. 823
Packet Pg. 824
Packet Pg. 825
Packet Pg. 826
Packet Pg. 827
Packet Pg. 828
Packet Pg. 829
Packet Pg. 830
Packet Pg. 831
Packet Pg. 832
Packet Pg. 833
Packet Pg. 834
Packet Pg. 835
Packet Pg. 836
Packet Pg. 837
Packet Pg. 838
Packet Pg. 839
Packet Pg. 840
Packet Pg. 841
Packet Pg. 842
Packet Pg. 843
Packet Pg. 844
Packet Pg. 845
Packet Pg. 846
Packet Pg. 847
Packet Pg. 848
Packet Pg. 849
Packet Pg. 850
Packet Pg. 851
Packet Pg. 852
Packet Pg. 853
Packet Pg. 854
Packet Pg. 855
Packet Pg. 856
Packet Pg. 857
Packet Pg. 858
Packet Pg. 859
Packet Pg. 860
Packet Pg. 861
Packet Pg. 862
Packet Pg. 863
Packet Pg. 864
Packet Pg. 865
Packet Pg. 866
Packet Pg. 867
Packet Pg. 868
Packet Pg. 869
Packet Pg. 870
Packet Pg. 871
Packet Pg. 872
Packet Pg. 873
Packet Pg. 874
Packet Pg. 875
Packet Pg. 876
Packet Pg. 877
Packet Pg. 878
Packet Pg. 879
Packet Pg. 880
Packet Pg. 881
Packet Pg. 882
Packet Pg. 883
Packet Pg. 884
Packet Pg. 885
Packet Pg. 886
Packet Pg. 887
Packet Pg. 888
Packet Pg. 889
Packet Pg. 890
Packet Pg. 891
Packet Pg. 892
Packet Pg. 893
Packet Pg. 894
Packet Pg. 895
Packet Pg. 896
Packet Pg. 897
Packet Pg. 898
Packet Pg. 899
Packet Pg. 900
Packet Pg. 901
Packet Pg. 902
Packet Pg. 903
Packet Pg. 904
Packet Pg. 905
Packet Pg. 906
Packet Pg. 907
Packet Pg. 908
Packet Pg. 909
Packet Pg. 910
Packet Pg. 911
Packet Pg. 912
Packet Pg. 913
Packet Pg. 914
Packet Pg. 915
Packet Pg. 916
Packet Pg. 917
Packet Pg. 918
Packet Pg. 919
Packet Pg. 920
Packet Pg. 921
Packet Pg. 922
Packet Pg. 923
Packet Pg. 924
Packet Pg. 925
Packet Pg. 926
Packet Pg. 927
Packet Pg. 928
Packet Pg. 929
Packet Pg. 930
Packet Pg. 931
Packet Pg. 932
Packet Pg. 933
Packet Pg. 934
Packet Pg. 935
Packet Pg. 936
Packet Pg. 937
Packet Pg. 938
Packet Pg. 939
Packet Pg. 940
Packet Pg. 941
Packet Pg. 942
Packet Pg. 943
Packet Pg. 944
Packet Pg. 945
Packet Pg. 946
Packet Pg. 947
Packet Pg. 948
Packet Pg. 949
Packet Pg. 950
Packet Pg. 951
Packet Pg. 952
Packet Pg. 953
Packet Pg. 954
Packet Pg. 955
Packet Pg. 956
Packet Pg. 957
Packet Pg. 958
Packet Pg. 959
Packet Pg. 960
Packet Pg. 961
Packet Pg. 962
Packet Pg. 963
Packet Pg. 964
Packet Pg. 965
Packet Pg. 966
Packet Pg. 967
Packet Pg. 968
Packet Pg. 969
Packet Pg. 970
Packet Pg. 971
Packet Pg. 972
Packet Pg. 973
Packet Pg. 974
Packet Pg. 975
Packet Pg. 976
Packet Pg. 977
Packet Pg. 978
Packet Pg. 979
Packet Pg. 980
Packet Pg. 981
Packet Pg. 982
Packet Pg. 983
Packet Pg. 984
Packet Pg. 985
Packet Pg. 986
Packet Pg. 987
Packet Pg. 988
Packet Pg. 989
Packet Pg. 990
Packet Pg. 991
Packet Pg. 992
DRAFT
City of
Patterson
Water
Shortage
Contingency
Plan 2025
June 2026
woodardcurran.com
95 Third Street | 2
nd Floor
San Francisco, California 94103
800.426.4262
Packet Pg. 993
City of Patterson (0013240.00) i Woodard & Curran, Inc. 2025 Water Shortage Contingency Plan June 2026