City of Corona
Potable Water Master Plan
LIST OF TABLES
Table 4.1 – Historical Water Demand...........................................................................................................2 Table 4.2 – Yearly Meter Demands...............................................................................................................5 Table 4.3 – City of Corona’s Demand by Land Use .......................................................................................6 Table 4.4 – Sphere of Influence Demand by Land Use .................................................................................8 Table 4.5 – Average Demand By Pressure Zone .........................................................................................10 Table 4.6 –Water Production by Month (AF), 2016 - 2019.........................................................................13 Table 4.7– Water Production by Month (AF), 2020 - 2024.........................................................................13 Table 4.8 – Water Demand and Inefficiencies (AFY), 2016 - 2019 .............................................................15 Table 4.9 – Water Demand and Inefficiencies (AFY), 2020 - 2024 .............................................................15 Table 4.10 – Existing Demand and Peaking Factors....................................................................................17 Table 4.11 – Demand Factors for City of Corona and Sphere of Influence ................................................19 Table 4.12 – 2040 Average Demand Based on Demand Factors (City and SOI COMBINED)......................21 Table 4.13 – Future Water Use and Demands (MGD) ................................................................................22
LIST OF FIGURES
Figure 4.1 – Historical Water Demands (MGD) ............................................................................................3 Figure 4.2 – City of Corona’s Demand (AFY) by Land Use.............................................................................7 Figure 4.3 – Sphere of Influence Demand (AFY) by Land Use.......................................................................8 Figure 4.4 – Average Demand (AFY) By Pressure Zone...............................................................................11 Figure 4.5 – City of Corona’s Reclaimed Water Use (2018)........................................................................16 Figure 4.6 – Diurnal Curve During the Maximum Day Demand (September 3, 2024) ...............................18
City of Corona
Potable Water Master Plan
TABLE OF CONTENTS
SECTION 5 - SERVICE CRITERIA......................................................................................... 5-1
5.1. General Description............................................................................................................5-1
5.2. Design Criteria....................................................................................................................5-1
5.2.1. Wells ...................................................................................................................................5-1
5.2.2. Tank Storage .......................................................................................................................5-3
5.2.2.1. Operational Storage Recommendations..................................................................................5-5
5.2.2.2. Fire Suppression Storage..........................................................................................................5-6
5.2.2.3. Emergency System Storage......................................................................................................5-7
5.2.3. Booster Pump Stations .......................................................................................................5-7
5.2.3.1. Pump Station Configuration.....................................................................................................5-7
5.2.3.2. Pump Station Details................................................................................................................5-7
5.2.3.3. Pump Station Fireproofing .......................................................................................................5-8
5.2.3.4. Pump Station Backup Power....................................................................................................5-8
5.2.4. Pressure Reducing Stations (PRS) .......................................................................................5-8
5.2.4.1. PRS Capacity .............................................................................................................................5-8
5.2.4.2. PRS Details................................................................................................................................5-8
5.2.5. System Pressures................................................................................................................5-9
5.2.6. Transmission and Distribution Pipelines...........................................................................5-10
5.2.6.1. Pipe Velocity...........................................................................................................................5-10
5.2.6.2. Pipeline Redundancy and Looping .........................................................................................5-10
5.2.6.3. Required Pipeline Spacing......................................................................................................5-11
5.2.6.4. Pipeline Sizing.........................................................................................................................5-11
5.2.7. Fire Suppression................................................................................................................5-11
5.2.7.1. Fire Department Requirements for Accessory Dwelling Units (ADUs)...................................5-12
5.2.7.2. ADU Fire Sprinkler Requirements ..........................................................................................5-12
5.2.7.3. JADU Fire Sprinkler Requirements.........................................................................................5-13
5.2.8. Summary of Design Criteria ..............................................................................................5-13
5.3. Unincorporated Areas Design Criteria ...............................................................................5-16
5.3.1. Fire Flow Requirements for Unincorporated Areas..........................................................5-16
5.4. Planning Criteria...............................................................................................................5-16
5.4.1. Methodology.....................................................................................................................5-16
5.4.2. Average Service Life..........................................................................................................5-16
5.4.3. Performance Indicators ....................................................................................................5-18
5.4.4. Distribution System Maintenance Program .....................................................................5-18
5.4.4.1. Flushing ..................................................................................................................................5-18
5.4.4.2. Exercising and Servicing of Valves and Hydrants ...................................................................5-19
5.4.4.3. Leak Detection........................................................................................................................5-19
City of Corona
Potable Water Master Plan
5.4.4.4. Water Main Replacement and Repair....................................................................................5-19
5.5. Criteria for Using Reclaimed Water for Future Potable Reuse ............................................5-19
5.5.1. Methodology.....................................................................................................................5-19
5.5.2. Direct Use..........................................................................................................................5-20
5.5.3. Indirect Use.......................................................................................................................5-21
5.5.3.1. Use of Reclaimed Water in the City of Corona.......................................................................5-21
LIST OF TABLES
Table 5.1 – Storage Volume by Zone .........................................................................................................5-4 Table 5.2 – Zone Details.............................................................................................................................5-5 Table 5.3 – Operational Storage ................................................................................................................5-6 Table 5.4 – Fire Suppression Storage.........................................................................................................5-6 Table 5.5 – Potable Distribution System Pressure Requirements...........................................................5-10 Table 5.6 – Potable Distribution System Velocity Requirements............................................................5-10 Table 5.7 – Fire Flow Requirements and Fire Hydrant Location Criteria.................................................5-12 Table 5.8 – Summary of Design Criteria...................................................................................................5-14 Table 5.9 – Average Service Life of Facilities ...........................................................................................5-17 Table 5.10 – Average Service Life of Pipelines.........................................................................................5-18
City of Corona
Potable Water Master Plan
TABLE OF CONTENTS
SECTION 6 - HYDRAULIC MODEL DEVELOPMENT AND EXISTING SYSTEM ANALYSIS6-1
6.1. General Description............................................................................................................6-1
6.2. Hydraulic Model Development ...........................................................................................6-1
6.2.1. Hydraulic Model Formulation Steps...................................................................................6-1
6.2.2. Physical Data Inputs............................................................................................................6-1
6.2.3. Initial Boundary Conditions.................................................................................................6-2
6.2.4. Water Demand Data ...........................................................................................................6-2
6.2.5. System Operations Integration...........................................................................................6-2
6.3. Hydraulic Model History .....................................................................................................6-3
6.4. Hydraulic Model Calibration ...............................................................................................6-3
6.4.1. Calibration Approach ..........................................................................................................6-3
6.4.2. Evaluating Calibration.........................................................................................................6-4
6.4.3. Hydraulic Model Calibration Results Summary ..................................................................6-6
6.5. Existing Water Distribution Analysis....................................................................................6-7
6.5.1. System Pressures Analysis..................................................................................................6-7
6.5.2. Pipeline Capacity Analysis...................................................................................................6-7
6.5.2.1. Peak Hour Conditions...............................................................................................................6-7
6.5.2.2. Maximum Day Demand Plus Fire Flow Conditions ..................................................................6-8
6.5.3. Pumping System Analysis..................................................................................................6-10
6.6. Summary of Existing System Hydraulic Deficiencies...........................................................6-12
LIST OF TABLES
Table 6.1: Model Calibration Accuracy ......................................................................................................6-7 Table 6.2: Existing Pumping System Analysis...........................................................................................6-11 Table 6.3 – Existing System Hydraulically Deficient Pipes.......................................................................6-13
LIST OF FIGURES
Figure 6.1 – Time of Day Demand Curve ...................................................................................................6-4 Figure 6.2 – Calibration Results for the 1380 Zone Tanks .........................................................................6-5 Figure 6.3 – Calibration Results for the 1380 Zone Pump Stations...........................................................6-6 Figure 6.4 – Project 1060-1........................................................................................................................6-8 Figure 6.5 – Project 725-1..........................................................................................................................6-9 Figure 6.6 – Project 1220-2........................................................................................................................6-9 Figure 6.7 – Project 1220-3......................................................................................................................6-10
City of Corona
Potable Water Master Plan
TABLE OF CONTENTS
SECTION 7 - FUTURE SYSTEM MODELING AND ANALYSIS................................................ 1
7.1. General Description...............................................................................................................1
7.2. Future Hydraulic Model.........................................................................................................1
7.3. Future Potable Water System Analysis...................................................................................2
7.3.1. Water Supply Analysis............................................................................................................ 2
7.3.2. Storage Analysis..................................................................................................................... 4
7.3.3. Pumping System Analysis....................................................................................................... 4
7.3.4. Pipeline Capacity Analysis...................................................................................................... 6
7.4. Summary of Future (Buildout) Hydraulic Deficiencies ...........................................................11
LIST OF TABLES
Table 7.1 – 2040 Water Supply Analysis.......................................................................................................2 Table 7.2 – 2040 Water Supply Analysis.......................................................................................................3 Table 7.3 – 2040 Storage Analysis.................................................................................................................4 Table 7.4 – 2040 Booster Pump Station Analysis..........................................................................................5 Table 7.5 – Future System Hydraulically Deficient Pipes (Buildout Conditions: 2040) ..............................12
LIST OF FIGURES
Figure 7.1 – Project 905-1.............................................................................................................................6 Figure 7.2 – Projects 905-2 and 905-3 ..........................................................................................................7 Figure 7.3 – Projects 905-4 and 708-1 ..........................................................................................................8 Figure 7.4 – Projects 1060-1 and 1060-2 ......................................................................................................9 Figure 7.5 – Project 1380-1.........................................................................................................................10 Figure 7.6 – Project 1220-1.........................................................................................................................10
City of Corona
Potable Water Master Plan
TABLE OF CONTENTS
SECTION 8 - WATER QUALITY............................................................................................. 8-1
8.1. Methodology .....................................................................................................................8-1
8.2. Regulatory Requirements...................................................................................................8-1
8.2.1. Primary Drinking Water Standards.....................................................................................8-1
8.2.2. Secondary Drinking Water Standards.................................................................................8-7
8.2.3. Unregulated Contaminants.................................................................................................8-9
8.2.4. Disinfectants and Disinfection Byproducts Rule...............................................................8-12
8.3. Groundwater Quality........................................................................................................8-14
8.3.1. Nitrate...............................................................................................................................8-14
8.3.2. Turbidity............................................................................................................................8-15
8.3.3. Perchlorate........................................................................................................................8-15
8.3.4. Trichloro propane (1,2,3-TCP)...........................................................................................8-15
8.3.5. Total Dissolved Solids (TDS)..............................................................................................8-16
8.3.6. Manganese........................................................................................................................8-16
8.3.7. Perfluorooctane sulfonic Acid (PFOS) and Perfluorooctanoic Acid (PFOA)......................8-16
8.4. Imported Water Quality ...................................................................................................8-17
8.5. Blending...........................................................................................................................8-17
8.6. Water Age........................................................................................................................8-17
8.6.1. Tank Turnover...................................................................................................................8-18
8.6.2. Flushing.............................................................................................................................8-18 Key to Abbreviations...............................................................................................................8-33 Extended Abbreviations..........................................................................................................8-34
LIST OF TABLES
Table 8.1 – Primary Drinking Water Contaminants of Concern.................................................................8-2 Table 8.2 – Primary Standards: Clarity.......................................................................................................8-3 Table 8.3 – Primary Standards: Microbiological Contaminants.................................................................8-3 Table 8.4 – Primary Standards: Radioactive Contaminants.......................................................................8-4 Table 8.5 – Primary Standards: Inorganic Contaminants ..........................................................................8-4 Table 8.6 – Primary Standards: Synthetic Organic Contaminants & Pesticides/PCBs...............................8-5 Table 8.7 – Primary Standards: Volatile Organic Contaminants................................................................8-5 Table 8.8 – Lead and Copper Rule Monitoring ..........................................................................................8-5 Table 8.9 – Primary Standards: Major Sources in Drinking Water ............................................................8-6 Table 8.10 – Secondary Drinking Water Standards ...................................................................................8-8
City of Corona
Potable Water Master Plan
Table 8.11 – Secondary Standards: Major Sources in Drinking Water......................................................8-9 Table 8.12 – Unregulated Contaminants with no MCLs............................................................................8-9 Table 8.13 – Unregulated Contaminants with no MCL: Health Effects...................................................8-10 Table 8.14 – Federal Unregulated Contaminants Monitoring Rule.........................................................8-10 Table 8.15 – Other Parameters................................................................................................................8-11 Table 8.16 – Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) with Notification Levels, Analyzed by EPA Methods 533 and 537.1 ...........................................................................................................8-12 Table 8.17 – Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS): Health Effects ...............................8-12 Table 8.18 – Disinfection Byproducts of Concern....................................................................................8-13 Table 8.19 – Disinfection Byproducts, Disinfectant Residuals, and Disinfection Byproduct Precursors Federal Rule.....................................................................................................................................8-13 Table 8.20 – Disinfection Byproducts: Sources and Health Effects .........................................................8-14 Table 8.21 – Weekly Low Chlorine...........................................................................................................8-19 Table 8.22 – Monthly Low Chlorine .........................................................................................................8-22 Table 8.23 – Quarterly Low Chlorine .......................................................................................................8-26 Table 8.24 – Annual Low Chlorine ...........................................................................................................8-28
LIST OF FIGURES
Figure 8.1 – Weekly Water Quality Flushing Locations ...........................................................................8-19 Figure 8.2 – Monthly Water Quality Flushing Locations..........................................................................8-22 Figure 8.3 – Quarterly Water Quality Flushing Locations........................................................................8-26 Figure 8.4 – Annual Water Quality Flushing Locations............................................................................8-28
City of Corona
Potable Water Master Plan
TABLE OF CONTENTS
SECTION 9 - Master Plan Improvements............................................................................. 9-1
9.1. Recommended Improvements............................................................................................9-1
9.1.1. Recommended Improvements...........................................................................................9-1
9.1.2. Capital Improvement Plan ..................................................................................................9-1
9.2. Project Priorities.................................................................................................................9-2
9.3. Risk-Based Analysis Methodology.......................................................................................9-2
9.3.1. Storage Tank Risk Analysis..................................................................................................9-3
9.3.2. Water Treatment Plant Risk Analysis..................................................................................9-4
9.3.3. Pressure Reducing Station Risk Analysis.............................................................................9-5
9.3.4. Groundwater Production Well Risk Analysis ......................................................................9-5
9.3.5. Pump Station Risk Analysis.................................................................................................9-7
9.3.6. Pipeline Risk Analysis..........................................................................................................9-8
9.4. Basis of Planning Level Cost Opinions................................................................................9-10
9.5. Construction Opinion Assumptions...................................................................................9-11
9.5.1. Pipeline Cost Opinion........................................................................................................9-11
9.5.2. Facilities Cost Opinion.......................................................................................................9-12
9.6. W1: Water Distribution System Improvements .................................................................9-14
9.6.1. W1-1: Systematic Water Pipeline Replacement Considering Identified Deficiencies......9-15
9.6.2. W1-2: Water Meter Replacements...................................................................................9-22
9.6.3. W1-3: SCADA Improvements............................................................................................9-24
9.7. W2 Water Treatment Plant Improvements........................................................................9-25
9.7.1. W2-1: Temescal Desalter Water Treatment Plant Improvements...................................9-26
9.7.2. W2-2: Lester Water Treatment Plant Improvements.......................................................9-27
9.7.3. W2-3: Sierra Del Oro Water Treatment Plant Improvements (Existing CIP) ....................9-28
9.7.4. W2-4: Glen Ivy Well Treatment Improvements................................................................9-29
9.8. W3 Storage Tank Improvements.......................................................................................9-30
9.8.1. W3-1: Welded Steel Storage Tank Recoating ...................................................................9-31
9.8.2. W3-2: Pressure Zone 1380 Improvements.......................................................................9-32
9.9. W4 Well Improvements....................................................................................................9-33
9.9.1. W4-1: Systematic Groundwater Well Equipment Pumping Equipment Rehabilitation ...9-34
9.9.2. W4-2 New Well 34 ............................................................................................................9-36
9.10. W5 Booster Pump Station (BPS) Improvements...............................................................9-37
City of Corona
Potable Water Master Plan
9.10.1. W5-1: Systematic Booster Pump Station (BPS) Rehabilitation.......................................9-38
9.11. W6 Pressure Reducing Station (PRS) Improvements ........................................................9-40
9.11.1. W6-1: Systematic Pressure Reducing Stations (PRS) Rehabilitation ..............................9-41
9.12. Recommended Improvements Cost Opinion Summary ....................................................9-43
LIST OF TABLES
Table 9.1– Likelihood and Consequence of Failure Scoring for Wells.......................................................9-6 Table 9.2 – Likelihood and Consequence of Failure Scoring for Pumps....................................................9-8 Table 9.3 –Pipeline Typical Service Life based on 2021 GIS Data ..............................................................9-9 Table 9.4 – Likelihood of Failure Scoring of Pipelines..............................................................................9-10 Table 9.5 – Summary of Elements Used to Estimate Recommended Improvement Costs.....................9-11 Table 9.6 – Basis for Pipeline Construction Cost Opinion........................................................................9-12 Table 9.7 – Basis for Facilities and Infrastructure Construction Cost Opinion ........................................9-12 Table 9.8 - Summary of Construction Cost Classes..................................................................................9-13 Table 9.9 –Hydraulically Deficient Pipes..................................................................................................9-17 Table 9.10 – Systematic Water Pipeline Replacements 2026 Cost Opinion............................................9-19 Table 9.11 – AMI Project Summary .........................................................................................................9-22 Table 9.12 – Water Meter Count and Estimated Cost to Replace...........................................................9-23 Table 9.13 – Systematic Meter Replacement 2026 Cost Opinion ...........................................................9-23 Table 9.14 – City Provided SCADA Operations Improvements................................................................9-24 Table 9.15 –Lester WTP Improvements 2026 Cost Opinion....................................................................9-27 Table 9.16 –Sierra Del Oro WTP Improvements 2026 Cost Opinion .......................................................9-28 Table 9.17 –Glen Ivy Well Treatment Improvements 2026 Cost Opinion ..............................................9-29 Table 9.18 –Storage Tank Recoating 2026 Cost Opinion.........................................................................9-31 Table 9.19 – Welded Steel Storage Tank Potential End of Service Life ...................................................9-31 Table 9.20 – Pressure Zone 1380 New BPS and Pipeline 2026 Cost Opinion..........................................9-32 Table 9.21 – Well Rehabilitation 2026 Cost Opinion ...............................................................................9-34 Table 9.22 – Groundwater Well Pumping Equipment Rehabilitation Prioritization................................9-35 Table 9.23 – New Well 2026 Cost Opinion ..............................................................................................9-36 Table 9.24 – Systematic Booster Pump Station Equipment Rehabilitation 2026 Cost Opinion ..............9-38 Table 9.25 – Systematic Booster Station Equipment Rehabilitation Prioritization .................................9-39 Table 9.26 – Systematic PRS Rehabilitation 2026 Cost Opinion..............................................................9-41 Table 9.27 – Systematic Pressure Reducing Station Rehabilitation Prioritization..................................9-42 Table 9.28 – Recommended Improvements Cost Opinion Summary......................................................9-43
LIST OF FIGURES
Figure 9.1 – Likelihood and Consequence of Failure Score Zones.............................................................9-3 Figure 9.2 – Age of Water Treatment Plants in 2026 ................................................................................9-4 Figure 9.3 – Age of Pressure Reducing Stations in 2026............................................................................9-5
City of Corona
Potable Water Master Plan
Figure 9.4 – Age and Material of Wells in 2026.........................................................................................9-6 Figure 9.5 – Age and Material of Pump Stations in 2026 ..........................................................................9-7 Figure 9.6 – Remaining Pipe Service Life ...................................................................................................9-9
City of Corona
Potable Water Master Plan
LIST OF APPENDICES
Appendix A – Blending Program Technical Report/Opera ons Plan Appendix B – Western Municipal Water District (WMWD) Resolution No. 3166 Appendix C – Well Pump Efficiency Tests (SCE)
Appendix D – Corona’s Water Production Data
Appendix E – Water Audits
Appendix F – Site Visit Conditional Assessment
Appendix G – City of Corona’s Inventory
Appendix H – Deficient Pipelines within Areas of Concern Appendix I – Existing Model Calibration Curves
Appendix J – Planned Near-Term Developments
Appendix K – Hydraulically Deficient Pipe Project Cut Sheets Appendix L – Size Deficient Pipes and Pipelines Beyond Typical Service Life Appendix M – Undersized Dead-End Mains (Non-Deficient)
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SECTION 1 - EXECUTIVE SUMMARY
1.1. INTRODUCTION
1.1.1. Purpose of Potable Water Master Plan
This Potable Water Master Plan provides a comprehensive, long-range evaluation for the City of Corona (City) potable water system to support informed decisions about system reliability, capacity, regulatory compliance, and capital investments. This Master Plan documents existing system conditions, evaluates current and planning period water demands, incorporates hydraulic modeling to assess system performance, and identifies potential improvements to continue to meet service requirements.
1.1.2. Master Plan Organization
This Master Plan is organized into the following sections. • Section 1 – Executive Summary
• Section 2 – Existing Infrastructure
• Section 3 – Water Supply
• Section 4 -Water Use
• Section 5 – Service Criteria
• Section 6 – Hydraulic Model Development and Existing System Analysis • Section 7 – Future System Model and Analysis
• Section 8 – Water Quality
• Section 9 – Master Plan Improvements
1.1.3. Planning Period and Master Plan Approach
The Master Plan uses 2040 as the planning period because the City’s 2020-2024 General Plan identifies full buildout occurring around that year, providing a consistent basis for projecting future land use and associated water demands. This timeframe allows the City to evaluate long‑range system needs, plan for growth, and prioritize capital improvements in alignment with anticipated development through buildout.
This Master Plan integrates available system data including historical records, service meter and production meter data, GIS datasets, asset inventories, and hydraulic modeling, operational considerations, and established industry standards, including guidance from the American Water Works Association (AWWA) and applicable California regulatory agencies. As with most large, legacy water systems, the available data may be incomplete, estimated, inconsistent, or subject to uncertainty due to limitations in recordkeeping, asset age, meter accuracy, changes in system configuration, and operational variability. Where complete or definitive data were not available, reasonable engineering assumptions and professional judgment were applied to support planning-level evaluations.
The recommendations and Recommended Improvements identified in this Master Plan are conceptual in nature and are intended to inform future studies, detailed engineering design, environmental review, permitting, and funding decisions.
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1.2. EXISTING INFRASTRUCTURE (SECTION 2)
Section 2 provides a comprehensive summary of the City’s current potable water system infrastructure and provides a condition assessment primarily based on remaining service life of system assets.
1.2.1. Sphere of Influence
The Riverside County Local Agency Formation Commission (LAFCO) establishes the City’s sphere of influence (SOI), which includes areas within the City boundaries as well as neighboring communities such as Coronita, El Cerrito, and portions of Temescal Canyon. While the City provides service to most of its SOI, adjacent water purveyors—including the City of Riverside, Home Gardens County Water District, Western Municipal Water District, and Lee Lake Water District—also serve portions of these areas.
1.2.2. Pressure Zones
The City’s potable water system is organized into six pressure zones, further divided into subzones identified in this report, which collectively manage service elevations ranging from approximately 430 to 1,520 feet, with the highest system elevation at 1,640 feet. Each zone is supplied and regulated through a combination of storage tanks, booster pump stations, and pressure‑reducing stations, which together maintain reliable system pressures and facilitate operational flexibility throughout the distribution network.
The City’s water system exhibits significant operational complexity due to its elevation profile and interzone connectivity. Zones such as 905 and 1060 function as major hubs, receiving water from multiple sources and distributing it to higher elevation zones through booster stations and pressure-reducing stations. Interagency interconnections with Riverside, Norco, and Temescal Valley Water District provide emergency redundancy and regional supply coordination.
1.2.3. Infrastructure Facilities
The City provides potable water service to approximately 159,000 residents through approximately 46,000 service connections across a 39-square-mile service area. The water system is hydraulically complex, consisting of 22 pressure zones, inclusive of subzones, designed to accommodate service elevations from 430 feet to 1,520 feet above mean sea level. These zones are interconnected through a network of booster pump stations and pressure-reducing stations that maintain operational flexibility and ensure reliable service across varying topographies. Zones such as 905 and 1060 serve as critical distribution hubs, supplying water to multiple upstream and downstream zones and supporting inter-zone transfers during peak demand or emergency conditions.
1.2.3.1. Water Supply and Treatment
The City’s water supply is sourced from a combination of local groundwater and imported water, supported by an extensive network of wells, treatment facilities, and agency interconnections.
Groundwater is drawn from the Temescal and Bedford-Coldwater Basins through wells. Depending on the location of the well, groundwater is treated through the Temescal Desalter, which produces 10.4 million gallons per day (MGD) of reverse osmosis-treated water blended at Garretson Tank, or through the
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Granular Activated Carbon Water Treatment Plant. Imported water is purchased from Western Municipal Water District (WMWD) and delivered through four turnouts: WR‑19, WR‑24, WR‑33, and WR‑29 (inactive), conveying surface water from the Lower Feeder pipeline (untreated) and Mills pipelines (treated). The Lower Feeder Pipeline provides untreated surface water from WMWD to the City, which is treated by the Lester Water Treatment Plant and the Sierra Del Oro Water Treatment Plant. The Green River Treatment Plant was historically used to treat surface water from the WMWD, but the Green River Water Treatment Plant is currently inactive.
Potable water system reliability is reinforced through a network of interconnections and emergency supply facilities. The City maintains system interconnections with Norco (two 2,500 gpm connections), Home Gardens (880 gpm metered connection), the Arlington Desalter (3,500 gpm), and Riverside and Temescal Valley Water District, enabling bidirectional supply under specific operating conditions.
Emergency interconnections allow the City to receive or deliver water if treatment plants or major transmission facilities are offline.
Collectively, the City’s groundwater wells, imported water turnouts, treatment plants, and interagency connections provide a redundant and diversified potable water supply, ensuring operational resilience and capacity to meet both current and future system demands.
1.2.3.2. Storage and Distribution System Infrastructure Storage infrastructure consists of 18 tanks with capacities ranging from 0.5 to 6 million gallons, which are strategically located to provide operational and fire storage and maintain hydraulic grade lines. Four tanks also serve as blending tanks to maintain water quality. The distribution network comprises approximately 675 miles of pipelines, with 45 percent of the system consisting of 8-inch diameter mains and transmission pipelines of 14 inches or greater accounting for 14.5 percent of total length. Transmission mains (≥14 inches) account for 95 miles, while distribution pipelines (≤12 inches) account for 573 miles. The system also includes 20 booster pump stations, 32 pressure-reducing stations, and 15 flow control valves, all of which play a critical role in managing pressure transitions and maintaining system stability. Customer services include approximately 46,000 water meters, predominantly ¾-inch meters serving single-family residential units and larger meters serve commercial and industrial customers.
1.2.3.3. Water System Control and Safety and Safety Components The City’s potable water system includes an extensive set of control and safety components that support system reliability, pressure management, and emergency operations. The inventory includes blow‑off valves (most are 2‑inch), air‑relief and combination valves (primarily 1–2‑inch), and detector check/backflow control valves. The distribution system also utilizes approximately 11,500 main valves, nearly half of which are 8‑inch. These components, along with booster pumping, form the backbone of the City's pressure‑zone control strategy, enabling reliable operation and providing critical system isolation and fire-flow capability. System-wide reliability is supported by more than 9,000 fire hydrants.
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1.2.4. Infrastructure Condition and Reliability Analysis The condition and reliability of the existing infrastructure is evaluated primarily focusing on remaining service life analysis of major assets with consideration of pump efficiency data, where applicable. The analysis uses GIS asset data, SCADA records, staff interviews, and site inspections.
General results from the analysis are summarized below. • Evaluation of the City’s 23 groundwater wells finds that 3 wells operate below 50% pump efficiency, 7 wells between 50–60%, and 9 wells above 60%, while all carbon‑steel well casings (25‑year life) will have exceeded their service life by 2026; stainless steel casings (75‑year life) remain in good condition.
• Storage tank assessments confirm the system includes 5 steel tanks (50‑year life) and 13 concrete tanks (100‑year life), with the Hayden Tank already past 50 years but still performing well, and the Border Tank expected to reach 100 years of age in 2069; the Glen Ivy Tank has already been removed from service.
• Pump station evaluations show most facilities are 20 to 40 years old, beyond the typical 20‑year equipment life, with 17 stations operating above 60% efficiency and 2 stations operating below 50% efficiency and needing near‑term rehabilitation or replacement. • Pipeline condition analysis finds the City operates 667.75 miles of pipeline constructed from materials with varying service lives including asbestos cement (70‑year life), PVC (70‑year life), ductile iron (100‑year life), CMLC (100‑year life), and steel pipe (50‑year life). As of 2026, approximately 16 miles of pipeline have already exceeded their service life, and an additional 118 miles are projected to reach end‑of‑life by buildout in 2040. Coronita, Temescal Valley, El Cerrito, and Downtown include pipelines less than 8-inches in diameter.
1.3. WATER SUPPLY (SECTION 3)
Section 3 summarizes how groundwater and imported water collectively provide the City’s water supply and summarizes historic and current production trends.
1.3.1. Supply Sources and Historic Production
The City’s water supply is derived from two groundwater basins (Temescal and Bedford–Coldwater) and imported water sources conveyed through WMWD via the Lower Feeder (untreated) and Mills (treated) pipelines, supplemented by Arlington Desalter and interconnections. Groundwater from Temescal Basin dominates local production, while Bedford–Coldwater Basin potable wells are currently inactive.
Imported water is delivered primarily as untreated flow to Lester (WR‑19) and Sierra Del Oro (WR‑33), with treated deliveries via Mills (WR‑24) and intermittent Arlington Desalter supplementation.
Historic and recent production records for 2016–2024 indicate supply follows with seasonal variability, where summer supply is approximately twice winter production. Average total production is about 28.61 MGD (2016–2019) and 28.90 MGD (2020–2024), reflecting stability with operational balancing between
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local and imported supplies. Records for 2016–2024 document source contributions by basin, turnout, and interconnection.
1.3.2. Groundwater
Groundwater wells extract groundwater from the Temescal and Bedford-Coldwater Basins. Each basin is managed by a Groundwater Sustainability Agency (GSA) and has a Groundwater Sustainability Plan (GSP) as mandated by the Sustainable Groundwater Management Act.
From 2016 through 2024, average groundwater production from the basins ranged from approximately
12.9 MGD to 13.5 MGD, reflecting increased reliance on Temescal Basin wells following inactivation of the Glen Ivy well facilities. The Temescal Basin receives both natural and artificial recharge, including percolation from reclaimed water discharged from WRF 1 and WRF 2, which accounts for an estimated 25% of total basin inflow under the 2019–2068 baseline scenario. Sustainability modeling in the 2022 Temescal Basin Groundwater Sustainability Plan projects total basin inflow on the order of 21.6 to 21.9 MGD, with comparable outflows of 21.7 to 21.8 MGD, indicating that additional groundwater production is limited without increasing recharge volumes.
The Bedford‑Coldwater Basin provides a smaller but important supplemental groundwater source. The basin spans approximately 6,300 acres and is divided into two management areas—Bedford and Coldwater—under the 2021 Groundwater Sustainability Plan. Sustainable yields for the two areas are estimated at 2,047 acre-feet per year (AFY) for the Bedford Management Area and 5,088 AFY for the Coldwater Management Area, while the City extracts approximately 336 AFY of non‑potable water from Bedford‑Coldwater wells for irrigation use.
Groundwater quality varies by basin: the Temescal Basin is characterized by elevated nitrate, total dissolved solids, perchlorate, and emerging PFAS constituents (PFOS/PFOA), while the Bedford‑Coldwater Basin exhibits historic nitrate and TDS issues, requiring treatment at the City’s Temescal Desalter and GAC Water Treatment Plant for regulatory compliance. Together, the Temescal and Bedford‑Coldwater Basins provide a critical local supply that meets a substantial portion of current potable water demand while requiring careful monitoring and recharge management to maintain long‑term basin sustainability.
1.3.2.1. Wells and Production Capacity
Potable wells in the Temescal Basin are treated at the Temescal Desalter and/or GACWTP. A Drinking Water Source Assessment and Protection (DWSAP) program has been completed for each potable well.
The total design capacity for all wells is about 32,082 gpm (46.20 MGD), with active wells totaling 25,272 gpm (36.39 MGD), reflecting reduced output associated with aging equipment and declining pump efficiencies.
Individual well performance varies—for example, recent efficiency tests indicate capacities ranging from approximately 273 gpm (Well 26) to over 1,400 gpm (Well 22)—highlighting the importance of ongoing rehabilitation, pump replacement, and efficiency testing to maintain reliable groundwater production across the Temescal and Bedford-Coldwater Basin wellfields.
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1.3.3. Imported
Untreated imported water constitutes roughly 91% of the City’s imported portfolio, conveyed via Lower Feeder turnouts WR‑19 (to Lester WTP) and WR‑33 (to Sierra Del Oro WTP); WR‑29 is inactive along with the Green River raw booster and treatment plant.
Treated imported water is delivered via Mills Pipeline turnout WR‑24 (Henry J. Mills WTP) and intermittently via the Arlington Desalter interconnection, typically in summer months. Average imported volumes (AFY) across 2016–2019 and 2020–2024 demonstrate sustained reliance on WR‑19 and WR‑33 with decreasing dependence on WR‑24 and minimal Arlington deliveries in recent years.
1.3.4. Reclaimed Water – Supply, Demand, and Recharge
The reclaimed water program integrates treatment at WRF 1 (11.5 MGD permitted, secondary/tertiary), WRF 2 (3 MGD), and WRF 3 (1 MGD, membrane bioreactor; will be decommissioned), plus two non‑potable wells. Average combined reclaimed production is approximately 11.64 MGD. Policy (Ordinance 2854) requires use of recycled water where feasible. The Prado Settlement (1968 agreement with WMWD) obligates Corona to discharge an annual average of 1,625 AFY (1.45 MGD) to the Santa Ana River Watershed at FCS‑Creek, representing about 12.8% of reclaimed production. Beyond mandated discharge, tertiary effluent from WRF 1 and WRF 2 is recharged to Temescal Basin via Lincoln and Cota ponds; permitted tertiary capacity has been increased by the State Water Resources Control Board to 15.5 MGD. Remaining production serves the City’s non‑potable distribution (primarily for irrigation), substituting potable demand.
1.4. WATER USE (SECTION 4)
Section 4 establishes the City’s existing and future (2040 buildout) potable water demands by analyzing historical consumption, metered water‑use patterns, land‑use characteristics, and pressure‑zone distribution.
1.4.1. Water Use
1.4.1.1. Representative Demand Year and Historical Trends The City’s 2024 metered consumption data were selected as the representative demand year for this Master Plan because the dataset reflects stabilized community behavior, post-pandemic economic normalization, and typical commercial and residential occupancy patterns.
1.4.1.2. Historical Demand Trends
Annual water use increased through the 1990s and early 2000s, reaching a peak of approximately 42 MGD in 2007. Water use then declined significantly beginning in 2008, influenced by the economic recession, multiple statewide drought-response measures, and long-term conservation trends. In recent years, average annual water use has stabilized at approximately 28 to 30 MGD despite continued population growth, indicating improved water-use efficiency throughout the community.
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1.4.2. Water Demand
Water‑use characterization relies on City meter‑read datasets (account attributes and time‑stamped consumption), facility production flowmeters, and GIS land‑use layers to link meters to parcels and land‑use categories. Hourly patterns and peaking behavior are evaluated using SCADA tank level and flow records, and demands were aggregated by land use and by hydraulic pressure zone for modeling and planning. Missing or inconsistent meter attributes are reconciled via geospatial placement and assessor parcel overlays, ensuring accurate spatial assignment of meter loads to the correct parcels and land‑use categories. This protocol underpins subsequent development of area‑based demand factors (gpd/acre and gpd/DU) and demand projections to 2040, recognizing that future conservation, land‑use adjustments, reclaimed conversions, climate variability, and economic shifts may alter outcomes and therefore require periodic updates.
1.4.2.1. Water Demand By Land Use
When water demand is assigned to meters by land‑use classes via GIS correlation, it confirms that water demand across the City is strongly influenced by residential land uses. Residential land use accounts for approximately 81% of all potable water delivered in 2024, reflecting the City’s predominantly residential character and the substantial share of water used for domestic, irrigation, and household activities. In 2024, combined Single‑Family and Multi‑Family residential categories account for roughly four‑fifths of potable deliveries, consistent with the City’s predominantly residential character. Commercial, industrial, institutional, and other non‑residential categories collectively represent the remaining demand, with individual land‑use contributions detailed in the aggregated consumption summary table.
The City’s aggregation approach sums average‑day demands across all meters within each land‑use class, producing planning‑level totals rather than per‑parcel averages. These totals inform projection baselines and allow derivation of area‑based demand factors used for future scenario testing, infill assessments, and development review. They also provide a pathway to quantify potential potable offsets if irrigation‑oriented parcels are converted to reclaimed water supply as infrastructure expands.
1.4.2.2. Water Demand by Pressure Zone
Zone‑level aggregation of 2024 meter demands indicates Pressure Zone 905 exhibiting the highest overall demand due to its large service population and development density; Zones 1220 and 1060 follow, each at approximately two‑thirds to three‑fourths of Zone 905’s volume. Lower‑elevation zones such as 725, 780, and 820 show comparatively smaller demands, while increased consumption is anticipated in Zones 1380 and 1640 as undeveloped areas in the southern portion of the City build out. The resulting zone distribution provides critical inputs to the hydraulic model, validating storage turnover targets, pressure reducing station (PRS) setpoints, and booster run times.
The zone distribution frames expectations for future growth: southern hillside zones (1380 and 1640) are anticipated to increase as undeveloped areas build out, while largely built‑out zones (1060 and 1220) are expected to remain stable aside from densification at select infill parcels.
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1.4.2.3. Seasonal Variability
Records for 2016–2019 show an average of 32,048 AFY (28.6 MGD) with summer production peaking at about two times the amount of winter production. For 2020–2024, average annual production was 32,419 AFY (29.0 MGD), maintaining a similar groundwater/import split (roughly half from groundwater, of which the majority is treated through the Temescal Desalter) and displaying consistent seasonality. January and February represent the lowest months; August consistently exhibits the highest production (3,533–3,587 AF). Reconciling production with metered deliveries shows total losses in line with industry norms: audits indicate a decline from 9.5% (FY15/16) to 4.9% (FY18/19), and sustained performance between 3.26% and
4.17% during FY19/20–FY23/24. These values reflect ongoing pipeline rehabilitation, meter replacement programs, and tightened operational accounting, and they support confidence in demand baselines used for modeling and improvement planning.
1.4.3. System Losses
The City performs annual water audits to quantify total production, billed consumption, and unbilled authorized uses. The City’s water losses have steadily declined over time, decreasing from approximately
9.5 percent in FY 2015/2016 to 4.9 percent in FY 2018/2019. This improvement aligns with industry expectations for systems with ongoing meter replacement programs and pipeline rehabilitation activities.
From FY 2019/2020 through FY 2023/2024, losses remained consistently below the 5 percent benchmark, ranging between 3.26 percent and 4.17 percent, further indicating stable system performance and continued reliability in the City’s distribution network.
1.4.4. Reclaimed Water Use Opportunities
The reclaimed water program reduces potable demand by converting suitable irrigation and large landscaped parcels to recycled supply, subject to Title 22 tertiary treatment requirements. Historically (2018), reclaimed deliveries averaged 1,411 gpm (2,276 AFY) to city parks, schools, and commercial/industrial/multifamily landscapes, with additional potential identified along existing and planned reclaimed alignments. The Prado Settlement obligates a controlled average discharge of 1,625 AFY (1.45 MGD) to the Santa Ana River watershed, while WRF 1 and WRF 2 tertiary effluent supports Temescal Basin recharge via percolation ponds. As reclaimed capacity expands and distribution pipelines are extended, incremental potable offsets can be realized in irrigation‑heavy corridors; planning should evaluate lifecycle costs, retrofit feasibility, and air‑gap/backflow compliance alongside potable demand reduction benefits.
1.4.5. Existing System Demands and Peaking Factors
Identifying average day, maximum day, and peak hour demands is valuable for operating a reliable water system, as these benchmarks ensure adequate capacity for routine use, seasonal fluctuations, and shortterm surges without compromising service or system integrity. Peaking factors further characterize existing demand data.
• The existing Average Day Demand (ADD) of 24.03 MGD is calculated by using the City’s 2024 meter read-data and calculating the demand per land use and pressure zone.
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• The Maximum Day Demand (MDD), the highest single-day production recorded by SCADA during the reference year, occurred on September 3, 2024, with a total system demand of 41.2 MGD. • The Peak Hour Demand (PHD) according to SCADA data was 68.4 MGD and occurred on September 9, 2024.
Table 1.1 – Existing Demand and Peaking Factors
Load Demand Existing Demand
(MGD) Peaking Factors Existing Factor
Average Day Demand 24.0 - -
Maximum Day Demand 41.2 1.8 1.7
Peak Hour Demand 68.4 3.0 2.8
1.4.6. Area-Based Demand Factors and Buildout Projections Area‑based demand factors (gpd/acre or gpd/DU) provide a consistent method to translate land‑use plans into future water‑use estimates. For 2024, factors were derived from meter datasets and GIS acreages (with DU alignment for single‑family classes; multifamily factors based on acreage where DU counts were not reliably separable). Applying these factors to anticipated 2040 acreage and DU counts yields a projected 2040 ADD of approximately 32.42 MGD for the combined City and SOI. Interim year demands (2025–2035) are interpolated linearly for programmatic budgeting and phasing of capacity projects (e.g., PRSs, boosters, trunk mains, and storage). While these projections anchor capital planning, they should be revisited periodically to incorporate conservation trajectories, reclaimed conversions, densification, and regulatory changes.
1.4.7. 2040 Demand Projects
The future demands can be projected assuming full City build out by 2040. The existing demand from reference year 2024 is known from water meter data, and the demand for 2040 was calculated using areabased demand factors with the assumption the City will be built out. The demand in intermediate years between 2024 and 2040 was interpolated assuming annual demand will increase at a constant linear rate.
Table 1.2 – Future Water Use and Demands (MGD)
Year 2025 2030 2035 2040
ADD 24.55 27.18 29.80 32.42
MDD 44.20 48.92 53.64 58.36
PHD 73.66 81.53 89.39 97.26
1.5. SERVICE CRITERIA (SECTION 5)
Section 5 establishes the service and design criteria used to evaluate the performance, reliability, and capacity of the City’s potable water system.
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1.5.1. Design and Performance Standards
Design and performance standards are based from AWWA guidance, California regulatory requirements including fire code and residential code, and City’s standards (Fire Department and Department of Water and Power Design Policy). These criteria form the basis for hydraulic modeling, identifying system deficiencies, and developing future improvements, and they guide long‑term asset planning, maintenance programs, and reinvestment strategies.
The City’s water system must meet Average Day Demand (ADD), Maximum Day Demand (MDD), Peak Hour Demand (PHD), and fire-flow conditions without compromising service reliability. Storage reservoirs are required to balance diurnal demand fluctuations, provide fire suppression capacity, and maintain emergency reserves. Booster pump stations, pressure-reducing stations, and transmission pipelines are designed to maintain pressures between 60 and 120 psi under normal conditions, with minimum residual pressures of 40 psi during PHD and 20 psi during MDD plus fire flow. Pipeline velocities are limited to AWWA-recommended thresholds to minimize wear and maintain water quality.
1.5.2. Design Standards by Component
1.5.2.1. Well Design and Source Protection
New potable wells must comply with California DWR Bulletin 74, AWWA A100, and DDW standards.
Design considerations include casing diameter, material selection, and structural integrity to prevent cross-contamination and ensure long-term reliability. Well screens and gravel packs are engineered to optimize yield and minimize sediment intrusion, while sanitary seals prevent surface water contamination. Source Water Assessments and monitoring wells are required to evaluate hydrogeologic conditions and identify potential contaminating activities prior to construction.
1.5.2.2. Storage and Emergency Supply
The City maintains approximately 44.9 MG of storage capacity across multiple pressure zones, exceeding the required 32.44 MG. Storage components include operational, fire suppression, and terminal reserves.
Emergency supply planning assumes a seven-day outage scenario, requiring 168 MG of water. Combined tank storage and groundwater production capacity (approximately 17.8 MGD) meet this criterion, supported by interconnections with neighboring agencies for redundancy.
1.5.2.3. Fire Protection and Pressure Management
Fire-flow requirements range from 1,000 to 4,000 gpm depending on land use, with hydrant spacing and residual pressure criteria established by the California Fire Code and local fire authority. Pressure-reducing stations and booster pump stations are equipped with redundant pumps, telemetry, and backup power systems to maintain service during peak demand and emergency conditions.
1.5.2.4. Planning and Asset Management
Service life criteria for tanks, pipelines, and appurtenances guide long-term reinvestment planning.
Performance indicators such as leak frequency, corrosion activity, and maintenance findings inform
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prioritization of capital projects. Routine maintenance programs include valve exercising, hydrant servicing, flushing, and leak detection to preserve system integrity and water quality.
1.5.3. Service Life Planning Criteria
Service life establishes the expected useful lifespan of wells, tanks, pipelines, pumps, and other facilities, and therefore directly shapes the City’s long‑term reinvestment strategy. By comparing each asset’s age to its average service life, the City can identify which facilities are approaching end‑of‑life, prioritize replacements before failures occur, and forecast when major capital investments will be required. Assets with shorter service lives—such as pumping equipment (10–15 years), electrical systems (7–10 years), and meters (10–15 years)—drive more frequent reinvestment cycles, while long‑life assets like concrete tanks (100 years) and ductile iron pipelines (up to 110 years) support long‑range capital planning. Proactively aligning system improvements with service‑life expectations reduces emergency repairs, prevents unplanned outages, and ensures that system reliability, regulatory compliance, and water quality are maintained as infrastructure ages.
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1.5.4. Summary of Design Criteria
Table 1.3 – Summary of Design Criteria
Focus Design Criteria
Total Supply
Maximum Day Demand (MDD) The total supply to the system is equal to the total demand, defined as MDD.
Average Day Demand (ADD) The average day demand is determined using the demand factors specified in Table
4.8 located in Section 4 - Water Use. These demand factors are provided on a peracre and per-connection basis, tailored to specific land use types.
Storage
Tank Capacity Sum of Operational, Fire, and Terminal Storage Operational Storage 50% of Maximum Day Demand (MDD)
Fire Suppression Storage Each pressure zone shall contain fire suppression storage at least equal to the highest fire flow storage volume required in the zone based on actual land use in the zone. Refer to Table 5.7 to calculate the highest fire demand in the Zone.
Terminal Storage 10% of Tank Capacity
Emergency System Storage 7 days of ADD (7 times ADD)
Booster Pump Station
Pump Station Capacity Pump Stations must supply maximum day demand (MDD). Note: The booster pump stations must supply MDD plus fire flow in subzones served exclusively by a hydropneumatic booster pump station.
Pump Station Configuration At least one duty and one standby pump in parallel. The standby pump must be of the same size as the largest duty pump to maintain operations in the event the duty pump is offline.
Pump Station Details Pump stations should be equipped with modern pump controllers, flow meters, suction and discharge pressure gauges, proper isolation valves, and telemetry equipment to control operations through SCADA.
Pump Station Fireproofing Pump stations should be constructed of fireproof materials and provided with peripheral sprinkler systems.
Pump Station Backup Power They are equipped with standby generators and automatic transfer switches to operate during power outages.
Pressure Reducing Station (PRS)
PRS Capacity Should deliver the entire range of demands and fire flows PRS Details PRS should be constructed with a pressure relief valve to preclude excessive pressures in the service area. Each PRS should be equipped with flow meters and telemetry equipment to control operation through SCADA. Each PRS should have two pressure reducing valves (sized typically for high and low flows per service area).
Pipe Size and Velocity
Minimum Pipe Size 8-inch (12-inch where required by the City’s DWP Design Policy) Maximum Pipe Velocities PHD 5 fps
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Table 1.3 – Summary of Design Criteria
Focus Design Criteria
Maximum Pipe Velocities MDD + Fire
Flow
12 fps
System Pressures
Minimum Static Pressure Existing System: 50 psi
Future System: 60 psi
Maximum Static Pressure 120 psi
Preferred Static Pressure 60 psi – 120 psi
Minimum Residual Pressure Existing System: 40 psi during PHD Future System: 60 psi during PHD
Existing & Future System: 20 psi during MDD + Fire Flow Energy Conservation SCE operates Time-of-Use (TOU) rate schedules with evening on-peak periods (typically a 5-hour peak demand window between 4 PM and 9 PM or a 3-hour peak demand window between 5 PM and 8 PM). Pumping should be scheduled outside of the on-peak periods defined in the current SCE schedule, when practical.
Water Quality
Blending Blending stations are used to meet regulatory limits and internal targets for constituents identified in Section 8 (Water Quality).
Fire Flow Requirements
Single Family Residential 1,500 gpm for 2 hours with 20 psi residual pressure at a fire hydrant. The average spacing between hydrants is 300 ft. [1]
Multi-Family Residential 2,500 gpm for 2 hours with 20 psi residual pressure at a fire hydrant. The average spacing between hydrants is 250 ft. [1]
Schools/Commercial 3,000 gpm for 4 hours with 20 psi residual pressure at a fire hydrant. The average spacing between hydrants is 250 ft. [1]
Industrial Min. 3,500 gpm for 4 hours with 20 psi residual pressure at a fire hydrant. If building Needed Fire Flow (NFF) is more than 3,500 gpm, then use NFF. The average spacing between hydrants is 250 ft. [1]
[1] Hydrant spacing shall apply as listed unless otherwise approved by the City of Corona Fire Department.
1.6. HYDRAULIC MODEL DEVELOPMENT AND EXISTING SYSTEM ANALYSIS (SECTION 6) Section 6 describes the development and calibration of the City’s hydraulic model and uses the hydraulic model to analyze the hydraulic performance of the existing potable water system.
1.6.1. Hydraulic Model Development
Hydraulic modeling results presented in this Master Plan represent planning-level simulations of assumed demand and operating conditions and are sensitive to input assumptions, system connectivity, and operational practices. Actual system performance may vary due to changes in operations, infrastructure condition, future development patterns, regulatory requirements, or climatic conditions.
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1.6.1.1. Hydraulic Model History and Formulation
To build an accurate representation of the water system, physical data—including pipes, junctions, storage tanks, wells, pump stations, and valve facilities— are input from the City’s GIS network and validated using as-built drawings and operator input. The modeling development process includes defining node elevations, pipe characteristics, pump performance curves, tank operating levels, and valve control settings within the Innovyze InfoWater software hydraulic model. Initial boundary conditions are set based on tanks levels and the initial open/closed setting for control valves and pumps. City Operations staff provided input about normally closed valves and current operational status and functionality for the City‘s PRS.
Metered demands, water supplies, pumped flows, and changes in tank volumes are reviewed to determine daily diurnal demand patterns. Annual consumption by metered account provides a spatial distribution of system demand.
1.6.1.2. Hydraulic Model Calibration
Calibration of the hydraulic model is essential to ensure its predictive accuracy. The City provided one month of SCADA tank levels, pump station flows, and pressure data to support calibration efforts. An extended period simulation (EPS) was performed to evaluate how the system behaves over a minimum 24-hour cycle, including tank drawdown and refill patterns.
Hydraulic model calibration is an iterative process of refining data and evaluating whether the hydraulic model captures the key operational characteristics of the potable water system. Graphical representations tank levels and pump station operations at each pressure zone are evaluated to analyze how well the hydraulic model is calibrated to the existing system conditions Some localized differences between modeled and field data points are expected. In complex potable water systems where looping and connectivity allows for numerous flow pathways, achieving an exact one‑to‑one alignment with every field data point is unlikely; however, graphical representations show the calibrated model successfully reproduced the behaviors of the system and closely reflects the SCADA‑recorded conditions over the calibration period. The model accurately reflects overall system trends including tank filling and drawdown patterns, pump station operation sequences, and system pressure responses.
The difference between field measured storage tank levels and hydraulically modeled tank levels is a common parameter used to assess the accuracy of calibration. A guideline for assessing hydraulic model calibration is less than two (2) foot difference between field measured and hydraulically modeled tank levels 80 percent of the time, and less than five (5) foot difference 100% of the time. The primary locations where the City’s hydraulic model sees larger differences between field measured tank levels and hydraulically modeled tanks levels are near the Garretson and Mangular Sites and blending facilities due to the complexity of these sites, which is rather common for such models. However, further refinement of the model must be balanced with the practical limitations of available data, staff effort, and project resources, recognizing that beyond a certain point, additional calibration effort yields diminishing improvements in accuracy relative to the cost and effort required.
The newly constructed and calibrated hydraulic model accurately reflects system operations and provides a strong basis for evaluating deficiencies and planning future improvements.
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1.6.2. Existing Potable Water System Analysis
Existing system analysis analyzes system pressures, pipeline capacity through velocity, existing booster pump capacity, and fire flow capabilities based on the service criteria established in Section 5.
1.6.2.1. System Pressure Analysis
The calibrated hydraulic model is reviewed to identify areas of low pressure. The City’s water system as modeled exhibits excellent pressure contours throughout. As expected, there are small areas around tanks and suction sides of pump stations and valving facilities, as well as at high points, where pressures are less than 40 psi. However, none of these areas are cause for improvements.
1.6.2.2. Pipeline Capacity Analysis
Velocity is a key component of pipeline capacity because it reflects how efficiently a pipe can convey flow under high‑demand conditions; as flow approaches the pipe’s hydraulic capacity, velocities increase, making velocity exceedances a practical indicator that the pipe is operating beyond its intended capacity.
Pipelines are evaluated during peak hour demand and maximum day demand plus fire conditions to identify velocities exceeding City standards. Pipeline capacity analysis under peak hour demand revealed that most pipelines operate below the five (5) feet-per-second (fps) threshold, with one exception documented in the existing hydraulic deficiencies. One notable exception is the 14-inch pipeline along Border Avenue (Zone 3 – 1060), where velocities reached up to 8.5 fps.
1.6.2.3. Booster Pumping Analysis
The City’s existing potable water distribution system includes multiple booster pump stations operating within interconnected pressure zones supported by storage facilities and pressure- and flow-regulating valves. System operations allow water to move through different pathways depending on system demands, storage levels, and control settings. Booster station capacity appears sufficient when compared with existing maximum day demands, recognizing that pump operation varies based on operational configuration and real-time system conditions. The existing system displays stable tank cycling behavior and sufficient operational storage under normal conditions, as confirmed by EPS calibration results.
1.6.2.4. Fire Flow Analysis
Fire flow performance is evaluated under the MDD plus fire flow scenario. As expected, fire flow limitations correlate with areas containing undersized distribution mains. Dead-end services and older small-diameter pipelines (4- and 6-inch) present constraints in delivering the minimum residential or commercial fire flow requirements. These areas are known system conditions and are typically addressed as part of broader pipeline replacement programs.
1.6.3. Findings from the Existing System Hydraulic Analysis The existing system analysis confirms that the City’s potable water distribution system performs reliably under current operating conditions. System pressures are generally in alignment with City standards,
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pipeline velocities are acceptable with one localized exception, and fire flow performance aligns with known limitations associated with undersized legacy mains.
1.6.3.1. Existing System Hydraulic Deficiencies
Hydraulically Deficient Pipes. Due to the City’s highly gridded, looped, and efficient potable water system, only five (5) projects were identified as hydraulically deficient under existing conditions. Hydraulic deficiencies—identified in the model based on high velocities, low pressures, inadequate fire flows, and elevated velocities during fire flow conditions—were consolidated into specific project cutsheets provided in Appendix K. Projects identified based on hydraulic deficiencies within the existing system are incorporated into Recommended Improvements in Section 9.
Table 1.4 – Existing System Hydraulically Deficient Pipes Zone (Existing Diameter)
Proposed Diameter Location Length(LF) Hydraulic Deficiency Priority 725 (10")
12"
Green River Road at Dominguez
Ranch 290 Fire Velocity > 12 fps Low
905
(12")
16"
Small segment in Railroad St east
of Alcoa Cir 21 Fire Velocity > 12 fps Low
(10")
16"
Alcoa Cir north of Railroad up to
Alcoa PRS 1,025 Fire Velocity > 12 fps Low
1060 (14")
16"
Border Ave between Ontario Ave
and Carolwood Dr 994 Velocity > 5 fps(Ultimate 5.6 fps) Low 1220
(6")
12"
400' South of Magnolia Ave and S
Main Street 380 Fire Velocity > 12 fps Med
(6")
8"
Grandview St between Consul Ave
and Diplomat Ave 380 Fire Velocity > 12 fps Med
Size-deficient pipes. Size-deficient pipes were identified based on the City’s Department of Water and Power (DWP) Design Policy (Nov 2012), Section B.6, which establishes minimum pipeline sizes (Section
5.2.6.4). Appendix L includes figures and tables identifying size-deficient pipes which are determined based on City design standards independent of hydraulic modeling results. The identified pipelines include dead-end mains less than 8-inches that serve hydrants and are therefore expected to meet the minimum size criteria. Recommendations for upsizing these pipelines, where applicable, are discussed in Section 9.
Pipelines Beyond Typical Service Life. Pipelines beyond their typical service life, determined by material type, are also identified in Appendix L. Figures and tables highlighting pipelines that have exceeded, or will exceed, their typical service life by 2040.
Reference Only (Not Recommended for Improvement): Non-Deficient Dead-End Pipelines Not all pipelines under 8 inches are considered size-deficient. Dead-end pipelines less than 8 inches in diameter that extend past the last hydrant and primarily serve residential connections are considered service extensions and are not recommended for upsizing. These non-deficient dead-end pipelines are included for reference in Appendix M.
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1.7. FUTURE SYSTEM MODELING AND ANALYSIS (SECTION 7)
Section 7 uses the calibrated hydraulic model along with projected 2040 buildout demands to analyze the hydraulic performance of the future potable water system.
1.7.1. Future Hydraulic Model
Similar to the existing system analysis, projections of future demands, system needs, and infrastructure performance are inherently uncertain and should be interpreted as planning-level indicators rather than guarantees of future conditions.
This future model is developed from the calibrated existing system hydraulic model, future demand projections established in Section 4, and the design and operational criteria outlined in Section 5. The future model assumes that the hydraulically deficient project identified in the existing system analysis is complete. The future model retains existing undersized pipelines rather than assuming full upsizing to City standards, as comprehensive replacement represents a substantial capital investment unlikely to be completed within the planning period. This hydraulic modeling approach provides a conservative assessment of future system performance while recognizing that some targeted upsizing may occur.
Water demands are assigned to the future hydraulic model based on projected conditions described in Section 4, including growth within the existing system and SOI, planned near-term development areas with conceptual designs, and land‑use‑based projections in areas without defined plans. Demands for future developments were added at anticipated connection points to evaluate whether the existing transmission system can support fire‑flow and operational needs without designing the off‑site facilities that will ultimately be required to supply water to future development.
The near-term developments considered in the future hydraulic model are summarized below. Planning documents for these developments are provided in Appendix J. • Arantine Hills Holdings, LP (TTM 38572) – Residential development of 85.51 acres • Green River Ranch Business Park (PM 37963) – Commercial development of 42.56 acres • Skyline Heights Phase 1, 2, 3 (TTM 36544) – Residential development of 249.39 acres
1.7.2. Future Potable Water System Analysis
1.7.2.1. Water Supply Analysis
The maximum day demand for 2024 and 2040 maximum day demand projections is compared to the currently available supply sources using both design capacity and actual capacity. The City maintains a combined available supply of 65.7 MGD, which remains sufficient to meet the projected 2040 maximum day demand of 58.4 MGD. This confirms that the City retains an adequate supply buffer through buildout.
Notably, the Arlington Desalter is not included in the base supply calculation, as its role is emergency and peaking support rather than sustained daily use.
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Table 1.5 – 2040 Water Supply Analysis
Demand Scenario Demand (MGD) Available Supply (MGD)
2024 Max Day Demand 43.2 65.7
2040 Max Day Demand 58.4 65.7
1.7.2.2. Storage Analysis
Future storage capacity analysis operational, fire flow, and terminal storage requirements for each pressure zone under 2040 buildout demand conditions. Total future tank storage across all zones amounts to 48.0 MG. Additional storage contributions from Skyline Heights Zone 5 (2.5 MG) and Zone 6A (0.6 MG) must be incorporated into final totals. Storage improvements must be timed with development-driven demand increases to ensure zone-level adequacy. Individual tank sizing and timing remain dependent on fire protection criteria, hydraulic gradeline constraints, and operational balancing among adjacent zones.
1.7.2.3. Booster Pumping Analysis
Due to the potable water system’s interconnected configuration, booster pump stations are not evaluated by direct comparison of pumping capacity to the MDD of an individual pressure zone. Under normal and peak demand conditions, water may enter or leave a zone through a combination of direct supply, pumped transfers, and pressure-regulated connections. As a result, a simple capacity-to-demand comparison does not reliably indicate whether a booster station provides adequate support to the system.
Booster station adequacy is therefore determined by model behavior under maximum day demand scenarios. Key performance criteria include tank refill capability, pump cycle recovery, sustained pressure maintenance, and operational stability. Booster stations did not exhibit operational deficiencies in the hydraulic model and were considered to provide adequate support under projected 2040 buildout demand conditions.
1.7.2.4. Pipeline Capacity Analysis
Pipelines are evaluated during peak hour demand and maximum day demand plus fire conditions to identify high velocities. Pipeline capacity analysis under peak hour demand revealed some pipelines that operate slightly above the five (5) feet-per-second (fps) threshold, as documented in the future hydraulic deficiencies. A low priority was placed on these projects, and should the City move forward with these projects, they should coincide with street paving activities where possible. Two of the identified projects also exceed 12 fps during fire flow.
1.7.3. Findings from the Future System Hydraulic Analysis Potential deficiencies may arise from high velocities, low pressures, inadequate fire flows, or insufficient storage replenishment capability. Mitigation measures often include pipeline upsizing, inter-zone connection improvements, booster station upgrades, PRV modifications, and additional storage.
The future system analysis confirms that the City’s potable water distribution system is positioned to meet projected 2040 buildout demands, supported by diverse supply sources, robust storage infrastructure, and interconnected hydraulic pathways.
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1.7.3.1. Future System (Buildout) Hydraulic Deficiencies Due to the highly gridded, looped, and efficient potable water system, only eight (8) projects were identified as hydraulically deficient for the future system at buildout (2040). For the majority of projects identified, the velocity under peak hour demands is marginally above the 5 fps threshold, and the projects are considered low priority. Projects identified based on hydraulic deficiencies within the existing system are incorporated into Recommended Improvements in Section 9.
Table 1.6 – Future (Buildout 2040) Hydraulically Deficient Pipes Zone (Existing Diameter)
Proposed Diameter Location Length(LF) Hydraulic Deficiency Priority 905
(12")
16"
Smith Ave between Sherman Ave
and Border Ave connection to
existing 24" main
622 Velocity > 5 fps
(Ultimate 5.5 - 6.9 fps) Low
(12")
14" Radio Rd south of Quarry St 233 Velocity > 5 fps(Ultimate 5.1 fps) Low (12")
14"
6th Ave between Radio Rd and
Compton Ave 1,052 Velocity > 5 fps(Ultimate 6.1 fps) Low (12")
16"
Small segment in Railroad St east
of Alcoa Cir 21 Velocity > 5 fps(Ultimate 5.8 fps) Low
(10")
16"
Alcoa Cir north of Railroad up to
Alcoa PRS 1,025 Velocity > 5 fps(Ultimate 12.0 fps) Low (Sub
zone)
780
(10")
16" Alcoa Cir north of PRS to Rincon St 1,094 Velocity > 5 fps(Ultimate 12.0 fps) Low (10")
12"
Segment in Rincon St west of
Alcoa Cir 14 Velocity > 5 fps(Ultimate 6.9 fps) Low
1060 (8")
10"
Kroonen Dr between Newton Ln
and Peeler St 380 Velocity > 5 fps(Ultimate 5.3 fps) Low 1220
(12")
16"
I-15 crossing between Bedford
Canyon Road and Tuscany St 1,644 Velocity > 5 fps(Ultimate 6.1 - 8.6 fps) Low (16")
24"
Duncan Way from Plantation Cir to
the Hayden Reservoir 2,249 Velocity > 5 fps(Ultimate 6.1 - 8.6 fps) Low 1380 (16")
20"
Upper Dr from Orange Crest St to
Peregrin Dr 938 Velocity > 5 fps(Ultimate 6.8 fps) Med
1.8. WATER QUALITY (SECTION 8)
The City is committed to providing a safe, reliable, and high-quality potable water supply that meets or exceeds all regulatory requirements established by the U.S. Environmental Protection Agency (EPA) and the California State Water Resources Control Board (SWRCB), Division of Drinking Water (DDW).Compliance is maintained with all federal and state standards, and the City’s practices are designed to address both health-based and aesthetic water quality concerns. • Primary Standards: Enforceable limits for contaminants with direct health impacts; all monitored parameters are maintained below Maximum Contaminant Levels (MCLs). • Secondary Standards: Guidelines for taste, color, and odor; all measured values, except aluminum (which exceeded the individual secondary MCL but remained compliant on a running annual average), were below regulatory thresholds.
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• Unregulated Contaminants: Monitored for emerging risks; not subject to mandatory treatment but tracked for future regulation.
The City performs routine sampling and laboratory analysis in accordance with federal and state regulations, including the Safe Drinking Water Act (SDWA), Title 22 of the California Code of Regulations, and the Disinfectants and Disinfection Byproducts Rule (DBPR). Results are published annually in the Consumer Confidence Report (CCR) and incorporated into this Water Master Plan to document ongoing compliance and system performance.
1.8.1. Key Water Quality Data
Routine monitoring confirms compliance with primary standards for clarity, microbiological safety, radioactive elements, inorganic and organic contaminants, and volatile compounds. Turbidity levels remain well below regulatory thresholds, indicating effective filtration. Microbiological testing verifies absence of harmful pathogens, while inorganic constituents such as nitrate and perchlorate are managed through treatment and blending. Synthetic and volatile organic compounds are consistently maintained below state and federal limits. For example, turbidity in groundwater ranges from 0.1 to 0.55 NTU, well below the 5 NTU secondary standard and the 0.3 NTU treatment performance criterion. Nitrate concentrations after blending average 30 mg/L, below the 45 mg/L MCL. Perchlorate levels are reduced to below 4 µg/L through targeted treatment and blending strategies.
Water quality monitoring in 2024 demonstrated consistent compliance with regulatory limits across all major contaminant categories. The City’s blending and treatment strategies effectively control contaminant levels, ensuring safe and reliable drinking water. • Turbidity: Filtered water turbidity consistently ≤0.3 NTU in ≥95% of monthly measurements; groundwater turbidity ranged 0.1–0.55 NTU, well below the 5 NTU secondary MCL. • Microbiological Contaminants: No positive samples for total coliform or E. coli detected in 2024. • Radioactive Contaminants: Gross Alpha Particle Activity and Uranium levels remained below state and federal limits.
• Inorganic Contaminants: Nitrate concentrations in blended water averaged ~30 mg/L, below the 45 mg/L MCL. Perchlorate levels in treated/blended groundwater were maintained below 4 µg/L (MCL: 6 µg/L).
• Synthetic Organic Contaminants: 1,2,3-Trichloropropane (TCP) concentrations in finished water were kept below 3 ppt (MCL: 5 ppt).
• Volatile Organic Contaminants: Tetrachloroethylene (PCE) and Trichloroethylene (TCE) were detected in select wells but treated/blended to meet 5 µg/L MCLs. • Lead and Copper: 2023 sampling showed 3 sites exceeded the lead action level (15 ppb); no sites exceeded the copper action level (1.3 ppm).
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Secondary standards, including turbidity, manganese, and total dissolved solids, are monitored to preserve taste, color, and odor. All aesthetic parameters remain below the thresholds recommended by the EPA and adopted by the State of California.
1.8.2. Unregulated and Emerging Contaminants
The City proactively monitors unregulated and emerging contaminants, including Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS), under precautionary Notification Levels, to anticipate future regulatory changes and protect public health. Recent detections of PFOS and PFOA in groundwater prompted targeted treatment and blending strategies to achieve concentrations below both state and federal thresholds. In 2024, the EPA established MCLs for PFOS and PFOA at 4 ppt each, with compliance required by 2031. State Notification Levels are 6.5 ppt for PFOS and 5.1 ppt for PFOA, with Response Levels of 40 ppt and 10 ppt respectively. Wells exceeding these thresholds are treated at the Temescal Desalter and blended at Garretson Tank, reducing PFOS and PFOA concentrations to non-detect in finished water.
Participation in the Unregulated Contaminant Monitoring Rule (UCMR) program enhances data collection for national regulatory development and positions the City as a proactive leader in addressing emerging water quality challenges.
1.8.3. Disinfection and Byproducts
Disinfection is essential for microbial deactivation, but it may produce regulated chemical byproducts. The City’s operational controls ensure that both disinfectant residuals and byproducts remain well below regulatory limits.
• Disinfection Byproducts: Total trihalomethanes (TTHMs), haloacetic acids (HAA5), and bromate levels were consistently below MCLs.
• Disinfectant Residuals: Chloramines used for microbial control; residuals maintained within safe limits.
1.8.4. Operational Practices
The City employs advanced blending operations, treatment technologies, and distribution system maintenance to optimize water quality. Five blending facilities optimize water quality and maintain nitrate concentrations below regulatory limits. Active mixing systems in storage tanks prevent stagnation and reduce disinfection byproduct formation. Comprehensive flushing programs maintain chlorine residuals and remove sediments, supporting consistent water quality across all pressure zones. Flushing schedules include weekly, monthly, quarterly, and annual cycles, targeting over 100 locations citywide. Imported water from WMWD is treated at Lester and Sierra Del Oro plants before blending with groundwater, ensuring compliance with all regulatory standards.
1.8.5. Groundwater and Imported Water
The City’s groundwater meets all primary standards following treatment and blending. Nitrate and perchlorate levels are managed through operational controls and desalting processes.
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Imported water supplied by WMWD is sourced from the Metropolitan Water District (MWD) via the Colorado River and State Water Project. Imported water supplements local supplies and is treated and blended to ensure compliance with all standards. This approach provides flexibility and resilience in meeting system demand.
• Imported water from WMWD is treated and blended with local groundwater to meet all regulatory standards.
1.8.6. Conclusions
The City’s potable water supply consistently meets or exceeds all state and federal water quality standards. Strategic blending, advanced treatment, and proactive monitoring ensure the safety, reliability, and aesthetic quality of drinking water delivered to the community.
The City’s integrated program of treatment, blending, and system optimization demonstrates a proactive approach to regulatory compliance, emerging-contaminant management, and long-term public health protection. Continued investment in monitoring technologies and infrastructure will support sustained water quality and operational resilience well into the planning period.
Key findings include consistent turbidity performance below 0.3 NTU, nitrate blending strategies that achieve an average concentration of 2.3 mg/L during 2025 (well below the 45 mg/L MCL), and effective perchlorate mitigation through targeted treatment and blending. PFAS management remains a critical priority, with advanced treatment at the Temescal Desalter reducing PFOS and PFOA concentrations to below 10 ppt in finished water—significantly lower than both state and federal thresholds. Operational strategies such as active tank mixing and systematic flushing have minimized disinfection byproducts and preserved chlorine residuals across all pressure zones. PFAS treatment technologies, expansion of blending capacity, and enhanced monitoring for emerging contaminants ensure sustained regulatory compliance, protect public health, and maintain consumer confidence in water quality.
1.9. MASTER PLAN IMPROVEMENTS (SECTION 9)
Section 9 presents the Recommended Improvements—projects identified through the condition assessments and the existing and future system analyses in Sections 2, 6, and 7.
The Recommended Improvements are the result of this Master Plan effort and are identified independently of the City’s CIP. Where this master plan identifies improvements that are also included in the City’s Capital Improvement Plan Fiscal Year (FY) 2026-FY2035 at the time of the adoption of this Master Plan, those projects are denoted with (Existing CIP).
1.9.1. Risk-Based Framework
The risk-based analysis used was based on the intersection between the consequence of failure (CoF) and likelihood of failure (LoF). The CoF is used to evaluate the consequences, or impacts, which could affect the City, the water service users, or the public health and safety if a failure of that facility were to occur.
The LoF is used to evaluate the probability of a particular asset failing based on known information. Both the LoF and CoF are assigned a value between 1 (low) to 5 (high). A low LoF score indicates that the facility
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is not likely to fail, while a high LoF indicates the facility is likely to fail or has already failed. A low CoF score indicates that relatively little to no interruption of service or public safety threat would occur if the facility were to fail. Based on the intersection of the LoF and CoF, facilities fall within a low-risk, mediumrisk, or high-risk zone. High-risk assets include aging wells, pump stations with low efficiency, and pipelines nearing end of life.
1.9.2. Basis of Planning Level Cost Opinions
Note that planning-level cost opinions, presented in 2026 dollars, included in the Master Plan are provided for comparative evaluation and long-term financial planning only and may differ from final project costs as project scopes are refined and market conditions evolve.
The cost opinions are developed by applying a percentage factor for planning, design, construction management, contingency, and City Administrative and Legal Costs to the estimated construction opinion.
Table 1.7 – Summary of Elements Used to Estimate Recommended Improvement Costs Pipelines WTPs Tanks Wells
Booster
Pump
Stations
Pressure
Reducing
Stations
Estimated Construction Opinion
Planning 5% 5% 5% 5% 5% 5%
Design 10% 10% 10% 10% 10% 10%
Construction Management, Inspection,
and Materials Testing
15% 15% 15% 15% 15% 15%
Contingency 25% 25% 25% 25% 25% 25%
City Administrative and Legal Costs 5% 5% 5% 5% 5% 5%
1.9.3. Recommended Improvements
The Recommended Improvements were developed using a risk-based methodology applied across all major asset classes, including pipelines, water meters, water treatment facilities, storage tanks, groundwater wells, booster pump stations, and pressure reducing stations. Asset risk was evaluated based on the Likelihood of Failure (LOF) and Consequence of Failure (COF), informed by available condition data, asset age, operational performance, hydraulic modeling results, and professional engineering judgment.
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Table 1.8 – Recommended Improvements
Improvement No. Improvement Description
W1: Water Distribution System Improvements
W1-1 Systematic Water Distribution System Replacement Considering Deficiencies W1-2 Systematic Meter Replacement
W1-3 SCADA Improvements
W2: Treatment Plant Improvements
W2-1 Temescal Desalter WTP Improvements
W2-2 Lester WTP Improvements
W2-3 Sierra Del Oro WTP Improvements (Existing CIP)
W2-4 Glen Ivy WTP Improvements
W3: Storage Tank Improvements
W3-1 Welded Steel Storage Tank Recoating
W3-2 Pressure Zone 1380 Improvements
W4: Well Improvements
W4-1 Systematic Groundwater Well Pumping Equipment Rehabilitation W4-2 New Well 34
W5: Booster Pump Station Improvements
W5-1 Systematic Booster Pump Station Rehabilitation
W6-1 Systematic PRS Station Rehabilitation
1.9.4. Next Steps
Recommended Improvements identified in Section 9 reflect system needs identified through planninglevel analysis. Inclusion of the Recommended Improvements in the City’s adopted CIP and implementation schedule is subject to the City’s final prioritization, funding availability, environmental review, and detailed engineering design.
Financial planning is critical as escalating replacement costs highlight the need for long-term capital improvement planning and prioritization based on risk and remaining service life. The City’s approach to asset management, combined with its commitment to maintaining water quality and service reliability, will ensure the continued sustainability of its potable water system.
City of Corona Section 2 – Existing Infrastructure
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SECTION 2 - EXISTING INFRASTRUCTURE
2.1. GENERAL DESCRIPTION
The City of Corona Utilities Department (City) currently provides water service to approximately 159,000 people1through 46,000 domestic service connections to an area approximately 39 square miles in size.
This section summarizes the existing potable water system infrastructure, describes the condition of the potable water system infrastructure, documents the remaining service life, and explains the risk-based critical asset approach to capital improvement planning.
The potable water system infrastructure discussed in this section can be generally summarized under the following categories.
• Pressure Zones
• Water Supply and Treatment
• Storage and Distribution System Infrastructure
• Water System Control and Safety Components
• Customer Services (specifically water meters)
2.1.1. Sphere of Influence
The Riverside County Local Agency Formation Commission (Riverside LAFCO) is the regional planning authority that has responsibility for establishing spheres of influence (SOI) for each local agency in the County, including the sphere of influence for the City. The City generally provides water service to areas within its SOI. The City’s SOI includes areas within the City’s boundary and within neighboring jurisdictions, such as Coronita, an unincorporated area, and El Cerrito and portions of Temescal Canyon, censusdesignated places, in the County. Neighboring water purveyors also provide water service to portions of the City’s SOI. For example, the City of Riverside and the Home Gardens County Water District provide water service to the Home Gardens area in the easterly SOI; the Western Municipal Water District (WMWD) provides water service to the Eagle Valley area in the southerly SOI; and the Lee Lake Water District provides water service to portions of the Temescal Canyon area also in the southerly SOI. A map showing the boundaries of the City’s SOI can be found in Figure 2.2.
2.2. PRESSURE ZONES
The City’s potable water system consists of twenty-two (22) pressure zones that serve elevations varying from a low point of 430 feet to a high point of 1,520 feet. Tanks are placed at the same hydraulic grade as the service zone it servicesto maintain the pressure within the zone. Smaller pressure zones(or subzones) are supplied by larger pressure zones through pressure reducing stations or booster pump stations. A hydraulic schematic of the City’s system is shown in Figure 2.1. A map of all the City’s pressure zones can be found in Figure 2.2. Refer to Table 5.2 in Section 5 for a summary of pressure zone names and aliases. 1 City of Corona Brochure from ESRI 2024 data
2-1
2.5 MG 1640' HWL 2.0 MG 1380' HWL 4.6 MG 1380' HWL PAYETTE (4) EAGLE GLEN ZONE 6 (3+FIRE)2.5 MG 1220' HWL 1.6 MG 1220' HWL EAGLE GLEN ZONE 5 (2) 4.0 MG 1220' HWL WELL 21 WELL 20 WELL 3 H AQUINO (2) 6.0 MG 1020' HWL ORANGE HEIGHTS 4.0 MG 905' HWL H MORITA (2 + FIRE) ARCADIA WELL 7A WELL 13 DROP VALVE 2.0 MG 1060' HWL 2.0 MG 1060' HWL LESTER ZONE 4 (4) LESTER ZONE 5 (5) CHASE (4) MWD WR-19 2.5 MG 905' HWL CRESTA VERDE (4) LESTER RAW (2) GARRETSON ZONE 3 (6) WELL 28 WELL 29 WELL 26 TEMESCAL DESALTER WELLS WELL 9A WELL 25 WELL 31 WELL 22 TEMESCAL DESALTER SAMPSON FCS WELL 14 WELL 15 WELL 27 WELL 12A WELL 11A WEST WELLS 2.0 MG 905' HWL 3.0 MG 1020' HWL HARLAN HILLS (2+FIRE) MABEY CANYON (2+FIRE) TO ZONE 1310 1.6 MG 1220' HWL BORDER (3) AVENIDA DEL VISTA 4.0 MG 1060' HWL MONTANA RANCH (2) MWD WR-33 SDO RAW (3) 9.1 MGD KRAFT RANCH (2+FIRE) TO ZONE 1315 SERFAS CLUB (2) 1.5 MG 725' HWL 725 (Zone 1) 905 (Zone 2)
1060 (Zone 3)
1220 (Zone 4)1380 (Zone 5)1640 (Zone 6) B 30.0 MGD Pipe (color-coded by pressure zone - see Pressure Zone Legend) X.X MG XXXX HWL Potable Water Tank Pump Station Water Treatment Plant X.X MGD B Blending Facility Distribution to customers Well Collection Lines Groundwater Well Connection to MWD MWD WR-X City of Corona Figure 2.1 Existing Water System Hydraulic Schematic SONRISA MOUNTAIN GATE CAJALCO ARLINGTON DESALTER 905 TO NORCO 1
RIVER & KALUS
HARRINGTON
ALCOA
NORTH SMITH
SOUTH SMITH
YORBA
AUTO CENTER DR
RIDGELINE
GREEN RIVER DOMINGUEZ RANCH H Hydropneumatic tank MILLS CONN Mills Connection ZONE 725 ZONE 820 ZONE 780 WELL 8A WELL 17A WELL 32 WELL 33 GACWTP GACWTP Common Well Valves CWXX 15.0 MGD Zone Valve (normally closed) Inactive Pump Station *MILLS CONNECTION BEDFORD CANYON TO ZONE 1480 SIERRA BELLA EAST SIERRA BELLA WEST TO ZONE 1250 SIERRA BELLA (2) Inactive Groundwater Well FREEDOM Temescal Desalter Pipeline 1020 CW19 MANGULAR ZONE 4 (3) MANGULAR ZONE 3 (2) TO ZONE 1235 TO ZONE 1130 TO ZONE 1220 Sustaining Station Flow Meter TO NORCO 2 TEMESCAL WEST TO/FROM CITY OF RIVERSIDE ZONE 925 B GARRETSON ZONE 4 (3) TEMESCAL EAST TVWD Temescal Valley Water District TVWD 1320 TVWD 2 (1) TVWD 1
YUMA VILLAGE LOOP TO ZONE 1045MAGNOLIAZONE 920 TO HOME GARDENS ZONE 920 & TANK M M M AD Arlington Desalter AD TO ZONE 1060 GREEN RIVER *MILLS CONNECTION LESTER 2.0 MG 905' HWL TO HOME GARDENS YUMA RELIEF VALVE Relief Valve ARLINGTON DESALTER 1060 H CW22 WELL 19 EAST WELLS HUMMING BIRD TO ZONE 960
SAN PONTE
MT SERENATA NICHOLAS FC Check Valve H H H 780 820 920 Home Gardens 1045 Arcadia 1060 Freedom 1310 Mabey Canyon 1130 Aquino 1235 Morita *MILLS CONNECTION TOM BARNES 1 MG MWD WR-29 X.X MGD Inactive Water Treatment Plant Inactive Connection to MWD MWD WR-X 960 Hummingbird 1315 Kraft Ranch 1136 Glen Ivy 1220 Montana Ranch 1250 Sonrisa 1480 Orange Heights *MILLS CONNECTION BEDFORD CANYON MWD WR-24 *MILLS CONNECTION LESTER *MILLS CONNECTION TOM BARNES TO ZONE 1380 TO ZONE 1380 TO ZONE 1220 TO ZONE 1060 TO ZONE 1220 *MWD WR-24 CONNECTION 1000 1100 900 800 700 600 1200 1300 1400 1500 1600 1700 500 400 300 1000 1100 900 800 700 600 1200 1300 1400 1500 1600 1700 500 400 300 Granular Activated Carbon Water Treatment Plant B Pressure Reducing Station or Flow Control Station (as noted) R-3 City of Corona Figure 2.1 Existing Water System Hydraulic Schematic RIVERSIDE EMERGENCY INTERTIE PRV
FCV
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Figure 2.2 – System Pressure Zone Map
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2.2.1. Zone 725 (Zone 1)
Zone Overview
Zone 725 is located in the western portion of the City’s service area, bounded by the 91 Freeway to the southeast and the City boundary to the west. The zone also includes a small commercial district north of Green River Road. Ground elevations within Zone 725 are generally below 600 feet above mean sea level (AMSL). The zone operates at the hydraulic grade established by the Green River Tank, which provides the controlling hydraulic grade line (HGL) for service pressures within the zone.
Storage Facilities
• Green River Tank
o Provides primary storage and establishes system pressures for Zone 725. o Historically supplied by the Green River Water Treatment Plant (WTP) and the WR-29 turnout (both currently inactive).
Supply Sources and System Interconnections
The current water supply to Zone 725 is delivered through the following inter-zone facilities:
• Dominguez Ranch Sustaining Station – Supplies water from Zone 905. • Nicholas Flow Control Valve – Supplies water from Zone 1060. • Green River Booster Pump Station – Lifts water from Zone 725 to Zone 1060.
Zone Characteristics
• Primarily residential areas with a small commercial corridor along Green River Road. • The inactive status of the Green River WTP and WR-29 turnout places full reliance on inter-zone supply from Zones 905 and 1060.
• Booster pump station capacity between Zones 725 and 1060 is important for operational flexibility.
• Pressure reducing stations (PRS) operations must maintain reliability due to their role as the primary supply source for the zone.
A system map illustrating Zone 725 boundaries and facilities is provided in Figure 2.3.
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Figure 2.3 – System Pressure Zone 725
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2.2.2. Zone 905 and Subzones (Zone 2)
Zone Overview
Zone 905 spans the City from east to west and is one of its largest pressure zones. It is bounded by Olive Street to the south, Zone 725 to the west, Zone 780 to the north, and Zone 1020 to the east. Ground elevations range from approximately 760 to 600 feet AMSL. The zone operates at the hydraulic grade established by its multiple storage tanks.
Storage Facilities
Zone 905 is supplied and pressurized by four storage tanks:
• R-3 Tank – Can serve Zone 905 directly and can receive water from Zone 1060 via the R-3 PRS. • Cresta Verde Tank – Supplies Zone 905, provides water to the Riverside Emergency Interconnection, and can supply Zone 1020 through the Cresta Verde BPS • Mangular Tank – Receives water from the West Wells and serves as a blending facility; supplies Zones 1060 and 1220 through the Mangular booster pump stations. • Garretson Tank – Receives water from the Temescal Desalter and Temescal Desalter Wells. While Garretson Tank serves as a blending facility and forebay for the two booster pump stations (Garretson Zone 3 BPS (supply to Pressure Zone 1060) and Garretson Zone 4 BPS (supply to Pressure Zone 1220)), it is not physically connected to Zone 905.
Supply Sources and System Interconnections
Zone 905 receives and distributes water through numerous inter-zone facilities, including:
• R-3 PRS – Transfers water from Zone 1060 into Zone 905. • Cresta Verde PRS – Transfers water from Zone 1020 into Zone 905. • Sampson FCV- Transfers water from Zone 1060 to Zone 905. • Garretson Booster Pump Stations – Lifts water to Zones 1060 and 1220. • Mangular Booster Pump Stations – Provide additional supply to Zones 1060 and 1220. • Interconnections – Water can also be transferred through Yuma Village Loop, Sampson, Avenida Del Vista, Ridgeline, Green River, San Ponte, and Mt. Serenata PRSs to lower pressure zones.
Zone Characteristics
• One of the most operationally critical and hydraulically complex zones in the system. • Receives water from multiple potable sources, including desalter wells and groundwater treatment facilities.
• Acts as a distribution hub, supplying multiple upstream higher elevation zones. • Redundancy is high due to the number of PRSs, tanks, and booster pump stations.
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A system map illustrating Zone 905 boundaries and facilities is provided in Figure 2.4.
Figure 2.4 – System Pressure Zone 905
NOTE: The “Hydrant” layer was turned off for this pressure zone, to showcase other GIS attributes.
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2.2.2.1. Subzone 780
Subzone Overview
Subzone 780 is located in the northernmost portion of the City. The zone extends from the City of Norco at the northeast boundary and continues south along Butterfield Park to the Railroad Street corridor. This subzone serves residential areas situated below approximately 600 feet AMSL. The zone operates under the hydraulic grade established by the upstream Zone 905 PRSs supplying this area.
Storage Facilities
Subzone 780 does not contain storage facilities. Pressure and supply conditions are maintained entirely through PRS operations from Zone 905.
Supply Sources and System Interconnections
Water is delivered to Subzone 780 exclusively from Zone 905 through the following pressure-reducing stations:
• River & Kalus PRS – Provides primary supply from Zone 905. • Harrington PRS – Secondary PRS supplying the southern portion of the subzone. • Alcoa PRS – Serves parcels east of Butterfield Park.
• North Smith PRS – Serves the western edge of Subzone 780.
Subzone Characteristics
• The subzone is entirely residential.
• All service pressures depend on reliable PRS functionality due to the absence of local storage. • The area includes several cul-de-sacs and looped mains that benefit from multiple PRS inputs. • PRS redundancy from four stations provides operational flexibility.
A system map illustrating Subzone 780 is provided in Figure 2.5.
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Figure 2.5 – System Pressure Zone 780
2.2.2.2. Subzone 820
Subzone Overview
Subzone 820 is located southwest of Subzone 780 and serves residential neighborhoods generally situated between Railroad Street to the south and Butterfield Park to the north. The zone is bounded to the east by Smith Avenue and to the west by the Prado Reservoir. Subzone 820 operates under the hydraulic grade supplied from Zone 905.
Storage Facilities
This subzone does not have dedicated storage facilities. Pressure and supply conditions originate from pressure reducing stations connected to Zone 905.
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Supply Sources and System Interconnections
Water is delivered from Zone 905 through the following PRS facilities:
• South Smith PRS – Serves the eastern portion of Subzone 820. • Yorba PRS – Serves the central zone along Yorba Street. • Auto Center Drive PRS – Provides supply to the western portion of the subzone.
Subzone Characteristics
• Subzone is primarily composed of commercial and industrial land uses. • All supply depends on PRS reliability; no local storage is provided. • Multiple PRSs ensure redundant supply paths.
A system map illustrating Subzone 820 boundaries and facilities is provided in Figure 2.6.
Figure 2.6 – System Pressure Zone 820
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2.2.3. Zone 1020 and Subzones
Zone Overview
Pressure Zone 1020 is located in the northeastern portion of the City. It is bounded by the City of Norco to the north, the 91 Freeway to the south, and the City of Riverside to the east. A small neighborhood located approximately half a mile west of the main zone footprint also falls within Zone 1020. Ground elevations in this zone are supported by the hydraulic grade established by the Yuma Tank.
Storage Facilities
Zone 1020 operates with one primary storage facility:
• Yuma Tank – Provides operational storage and establishes the hydraulic grade line for Zone 1020. • Border Tank – See Zone 1060.
Supply Sources, System Interconnections, and Intercity Connections Zone 1020 receives and distributes water through the following system interconnections:
• Incoming Supply:
o Cresta Verde Booster Pump Station – Lifts water from Zone 905 to Zone 1020. o Sampson PRS – Supplies water from Zone 1060 to Zone 1020. o Yuma Village Loop PRS – Supplies water from Zone 1020 back into Zone 905. o Aquino Hydro-Pneumatic Pump Station – Lifts water from Zone 1020 into Zone 1130. o Morita Hydro-Pneumatic Pump Station – Lifts water from Zone 1020 into Zone 1235. • Intercity Connections:
o Zone 1020 provides water to the City of Norco through two interconnections, commonly referred to as Norco-1 and Norco-2.
Zone Characteristics
• Zone 1020 is a major mid-elevation zone serving mixed residential neighborhoods. • It functions as both a receiving and distributing zone, supplying two higher-elevation zones (1130 and 1235).
• System performance depends on PRS reliability due to the zone’s dual role as both a supply and passthrough zone.
• The hydraulic configuration allows operational flexibility between Zones 905 and 1060. • The presence of City-to-City interconnection (Corona–Norco) adds an additional operational layer for regional supply coordination.
A system map illustrating Zone 1020 and its subzones is provided in Figure 2.7.
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Figure 2.7 – System Pressure Zone 1020
2.2.3.1. Subzone 1130 (Aquino)
Subzone Overview
Subzone 1130 (Aquino) is a small, isolated high-elevation pocket located within the larger footprint of Zone 1020, generally surrounding Aquino Circle. This area requires a higher hydraulic grade than the surrounding neighborhoods, necessitating a dedicated boosted subzone.
Storage Facilities
Subzone 1130 does not contain any storage facilities. Pressures within the subzone are maintained entirely through pumping from Zone 1020.
Supply Sources and System Interconnections
Water is delivered to Subzone 1130 through:
• Aquino Hydro-Pneumatic Pump Station – Lifts water from Zone 1020 to Zone 1130. • No PRSs or inter-zone transfer facilities are associated with this subzone.
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Subzone Characteristics
• Very small service area.
• Fully dependent on Zone 1020 for supply.
• Operates as a localized boosted pocket to maintain adequate service pressures. • No downstream or lateral distribution; all flow remains within the subzone.
A system map illustrating Subzone 1130 is provided in Figure 2.8.
Figure 2.8 – System Pressure Zone 1130
2.2.3.2. Subzone 1235 (Morita)
Subzone Overview
Subzone 1235 (Morita) serves a small neighborhood located within the boundary of Zone 1020. The subzone includes portions of Baghdady Street, Wolfson Street, and Wycliffe Street. Due to the elevation in this area, it requires a higher pressure than Zone 1020 can supply directly.
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Storage Facilities
• Subzone 1235 does not include any storage tanks. Hydraulic grade is maintained solely by pumping from Zone 1020.
Supply Sources and System Interconnections
Water is supplied to Subzone 1235 through:
• Morita Hydro-Pneumatic Pump Station – Lifts water from Zone 1020 to Zone 1235. • No pressure-reducing stations or interconnections are associated with this subzone.
Subzone Characteristics
• Small, localized pressure zone created to meet elevation-specific pressure needs. • Entirely reliant on Zone 1020 and the Morita Hydro-Pneumatic Pump Station for water supply. • Contains no supplemental facilities such as storage or PRS assets. • Functions solely as a boosted high-elevation extension of Zone 1020.
A system map illustrating Subzone 1235 is provided in Figure 2.9.
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Figure 2.9 – System Pressure Zone 1235
2.2.4. Zone 1060 and Subzones (Zone 3)
Zone Overview
Pressure Zone 1060 spans the central portion of the City of Corona and serves customers at elevations ranging from approximately 760 to 920 feet above mean sea level (AMSL). The zone operates at the hydraulic grade established by the Lester, Sierra Del Oro, and Border Tanks, which collectively provide storage capacity and maintain system pressures throughout this area.
Zone 1060 includes a mix of residential, commercial, and institutional land uses. Due to its central location and elevation profile, Zone 1060 also serves as a major intermediate zone that supports water transfers to several higher-pressure zones.
Storage Facilities
Zone 1060 relies on four primary storage facilities, which establish the HGL, provide fire and operational storage, and maintain pressure stability throughout the zone:
• Lester Tank #1 – Provides primary operational storage for the central distribution area and stabilizes system pressures during varying demand conditions.
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• Lester Tank #2 – Functions alongside Lester Tank #1 to increase available storage volume and enhance system reliability during peak demand or supply interruptions. • Sierra Del Oro Tank – Supports the western portion of Zone 1060 by providing operational and fire storage and maintaining adequate pressures in the Sierra Del Oro and Green River areas. • Border Tank – Hydraulically part of Zone 1060 and provides operational storage and flexibility.
The tank may be drawn down to supply water to the Mangular Blending Facility which can pump blended water back into Zone 1060.
Supply Sources and System Interconnections
Zone 1060 receives water from multiple treatment plants and system interconnections, along with booster and pressure-reducing facilities that manage flow between adjacent zones:
• Lester Water Treatment Plant (WTP) – Treats and supplies potable water to Zone 1060. The plant receives water through the WR-19 turnout.
• Sierra Del Oro Water Treatment Plant (WTP) – Treats and supplies potable water to Zone 1060.
The plant receives water through the WR-33 turnout.
• Temescal Desalter – Supplies Zone 1060 through the Temescal Desalter pipeline and also contributes to the Garretson and Mangular systems.
• Garretson Zone 3 Booster Pump Station – Lifts water from the Garretson Tank to Zone 1060. • Lester Booster Pump Station – Lifts water from Zone 1060 to Zone 1220. • Chase Booster Pump Station – Lifts water from Zone 1060 to Zone 1220. • Montana Ranch Hydro-Pneumatic Pump Station – Lifts water from Zone 1060 to Zone 1220. • Border Booster Pump Station (BPS) – Lifts water from Zone 1060 to Zone 1380. • R-3 PRS – Transfers water from Zone 1060 to Zone 905. • Sampson PRS – Transfers water from Zone 1060 to Zone 905. • Magnolia PRS – Transfers water from Zone 1060 to Zone 905 and Home Gardens. • Arlington Desalter PRS – Supplies treated desalter water into Zone 1060. • Avenida Del Vista PRS – Transfers water from Zone 1060 to Zone 905. • Hummingbird PRS – Transfers water from Zone 1060 to Zone 905 and 960. • Ridgeline PRS – Transfers water from Zone 1060 to Zone 905. • Green River PRS – Transfers water from Zone 1060 to Zone 905. • San Ponte PRS – Transfers water from Zone 1060 to Zone 905. • Mt. Serenata PRS – Transfers water from Zone 1060 to Zone 905.
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• Serfas Club Booster and Pressure Reducing Station - Transfers water between Zone 1060 and Zone 905.
Zone Characteristics
• A centrally located, mixed-use service area that supports several surrounding higher and lower elevation zones.
• Multiple water treatment plants located within the zone. • Extensive inter-zone connectivity that enables operational flexibility. • Numerous PRSs and BPSs that maintain pressure balance and manage hydraulic transitions across adjacent zones.
• Strategic importance as a central distribution hub for Zones 905, 1220, and 1380.
A system map illustrating Zone 1060 boundaries, pipelines, and facilities is provided in Figure 2.10.
Figure 2.10 – System Pressure Zone 1060
NOTE: The “Hydrant” layer was turned off for this pressure zone, to showcase other GIS attributes.
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2.2.4.1. Subzone 920 (Home Gardens)
Subzone Overview
Subzone 920 (Home Gardens) is a small pressure subzone located within Zone 1060 near the eastern boundary of the City. The subzone is bounded by 6th Street to the north, All American Way to the south, and Dubley Way to the west. This subzone primarily serves residential areas at lower elevations within Zone 1060.
Supply Sources and System Interconnections
• Magnolia PRS – Supplies water from Zone 1060 to Subzone 920. • In addition to serving local demand, Subzone 920 also functions as a transfer point for water delivered from the City of Corona to the unincorporated Home Gardens community. This transfer is monitored through a dedicated flow meter located at the system boundary.
Subzone Characteristics
• A small, mostly residential service area located at the western edge of Zone 1060. • Reliance on a single PRS supply connection, which emphasizes the importance of reliable operations at the Magnolia PRS.
• Hydraulic positioning that allows the City to supply water to the adjacent unincorporated Home Gardens community under monitored conditions.
A system map illustrating Subzone 920 and its boundaries is provided in Figure 2.11.
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Figure 2.11 – System Pressure Zone 920
2.2.4.2. Subzone 960 (Hummingbird)
Subzone Overview
Subzone 960 (Hummingbird) is a small, embedded subzone situated between portions of Zones 905 and 1060. The subzone is bounded generally by Paseo Grande to the southeast and Pine Crest Drive to the west. The area consists primarily of residential neighborhoods requiring a localized elevated hydraulic grade.
Storage Facilities
This subzone does not contain any dedicated storage facilities. Pressures within the subzone are established through pumping from Zone 1060.
Supply Sources and System Interconnections
Water supply to Subzone 960 is provided through the following facility:
• Hummingbird PRS – Supplies water from Zone 1060 to Subzone 960.
Subzone Characteristics
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• A compact residential service area located between major system zones. • Full reliance on the Hummingbird PRS to maintain local pressures. • No direct storage, which increases the operational importance of dependable PRS performance.
A map of Subzone 960 is provided in Figure 2.12.
Figure 2.12 – System Pressure Zone 960
2.2.4.3. Subzone 1315 (Kraft Ranch)
Subzone Overview
Subzone 1315 (Kraft Ranch) serves the neighborhood located along Oakridge Drive, extending beyond the intersection of Oakridge Drive and San Ramon Drive. The area includes homes at higher elevations that require pumping to maintain adequate service pressure.
Storage Facilities
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• This subzone does not contain any dedicated storage facilities. Pressure is maintained through booster pumping from Zone 1060.
Supply Sources and System Interconnections
Water supply to Subzone 1315 is delivered through:
• Kraft Ranch Hydro-Pneumatic Pump Station – Lifts water from Zone 1060 to Subzone 1315.
Subzone Characteristics
• A hillside residential community requiring elevation-driven pressure boosting. • Complete dependence on the Kraft Ranch Hydro-Pneumatic Pump Station for both pressure regulation and supply continuity.
• No direct storage, which increases the operational importance of dependable PRS performance.
A map of Subzone 1315 is provided in Figure 2.13.
Figure 2.13 – System Pressure Zone 1315
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2.2.5. Zone 1136 (Glen Ivy)
Zone Overview
Zone 1136 (Glen Ivy) is located in the southernmost portion of the City’s service area within the Temescal Valley. The zone is bounded by Dos Lagos Drive to the north, Stellar Court to the south, the Estelle Mountain Range to the east, and Interstate 15 to the west. The zone includes a mix of rural and semi-rural development at higher elevations.
Storage Facilities
• Glen Ivy Tank – Provided primary operational storage and establishes the hydraulic grade for Zone 1136 and has recently been removed from service.
• Glen Ivy Tank historically stored water produced from the Glen Ivy Wells, which are currently inactive.
Supply Sources and System Interconnections
Water supply to Zone 1136 is delivered through the following facilities:
• Temescal East Sustaining Station – Supplies water from Zone 1220 to Zone 1136. • Cajalco PRS – Supplies water from Zone 1220 to Zone 1136. • Zone 1060 Interconnection – A zone valve connection that allows Zone 1060 to supply water to Zone 1136; this valve normally remains closed.
• Agency Connections:
• TVWD-2 Booster Pump Station – Lifts water from Zone 1136 to the Temescal Valley Water District.
• TVWD-1 PRS – Transfers water from the Temescal Valley Water District into Zone 1136.
Zone Characteristics
• A geographically isolated pressure zone dependent on two primary PRSs for continuous supply. • The presence of inactive Glen Ivy wells (Wells 3, 20, and 21) and out-of-service Glen Ivy Tank. • Critical inter-agency interconnections allowing bidirectional supply with the Temescal Valley Water District.
• Rural terrain and elevation changes influence hydraulic conditions and system operations.
A map of Zone 1136 is provided in Figure 2.14.
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Figure 2.14 – System Pressure Zone 1136
2.2.6. Zone 1220 and Subzones (Zone 4)
Zone Overview
Pressure Zone 1220 extends across the City from east to west and is generally bounded by Ontario Avenue to the north. The zone serves areas with ground elevations ranging from approximately 900 to 1,100 feet AMSL. Zone 1220 is a major high‐elevation zone in the City’s distribution system and supports both local demands and several dependent subzones.
Storage Facilities
• Hayden Tank – Provides operational and fire storage and establishes the hydraulic grade for the surrounding service area.
• Keith Tank – Provides operational storage for customers along the northern portions of the zone. • Upper & Main Tanks – Provide combined system storage supporting the central and southern areas of Zone 1220.
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• Avenida Del Vista Tank – Supports the eastern portion of the zone and maintains pressures for nearby subzones and interconnections.
Supply Sources and System Connections
Water is supplied to Zone 1220 through several inter-zone facilities:
• Mills Connection – Transfers water from Zone 1060 to Zone 1220. • Chase Booster Pump Station – Lifts water from Zone 1060 to Zone 1220. • Lester Zone 4 Booster Pump Station – Lifts water from Zone 1060 to Zone 1220. • Border Booster Pump Station – Lifts water from Zone 1060 to Zone 1220. • Mountain Gate PRS – Supplies water from Zone 1380 to Zone 1220. • Sonrisa PRS – Supplies water from Zone 1380 to Zone 1220. • Mangular Zone 4 Booster Pump Station – Lifts water from Zone 905 to Zone 1220. • Garretson Zone 4 Booster Pump Station – Lifts water from the Garretson Tank to Zone 1220.
Downstream supplies from Zone 1220 include:
• Cajalco PRS – Supplies water from Zone 1220 to Zone 1136. • Arcadia PRS – Supplies water from Zone 1220 to Zone 1045. • Freedom PRS – Supplies water from Zone 1220 to Zone 1060. • Mabey Canyon Hydro-Pneumatic Pump Station - Lifts water from Zone 1220 to Zone 1310 • Harlan Hills Booster Pump Station – Lifts water from Zone 1220 to Zone 1380 Zone Characteristics
• A large, continuous high‐elevation zone containing multiple storage tanks that maintain hydraulic grade.
• Significant inter-zone transfers, making Zone 1220 a central supply point for multiple dependent pressure zones.
• Operational complexity driven by numerous booster pump stations and PRSs that must coordinate to maintain pressures and storage turnover.
• A mix of residential neighborhoods situated in hillside terrain.
A map of pressure Zone 1220 is provided in Figure 2.15.
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Figure 2.15 – System Pressure Zone 1220
NOTE: The “Hydrant” layer was turned off for this pressure zone, to showcase other GIS attributes.
2.2.6.1. Subzone 1045 (Arcadia)
Subzone Overview
Subzone 1045 (Arcadia) lies within Zone 1220. The subzone is bounded by Minnesota Road to the north, East Ontario Avenue to the southwest, and Arcadia Street to the east. It serves a small residential neighborhood requiring a slightly lower hydraulic grade than Zone 1220. The City plans to eliminate the existing subzone and remove the associated PRS.
Storage Facilities
• This subzone does not include dedicated storage; pressures are established through PRS operation.
Supply Sources and System Connections
• Arcadia PRS – Supplies water from Zone 1220 to Subzone 1045. With the planned elimination of Subzone 1045, the Arcadia PRS will be removed from service.
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Subzone Characteristics
• Historically, reliant on the Arcadia PRS to maintain local pressures. The Arcadia PRS would no longer be required under the planned elimination of Subzone 1045. • A compact residential service area located adjacent to the main Zone 1220 distribution trunk lines.
A map of Subzone 1045 is presented in Figure 2.16.
Figure 2.16 – System Pressure Zone 1045
2.2.6.2. Subzone 1060 (Freedom)
Subzone Overview
Subzone 1060 (Freedom) is situated between Zones 1060 and 1220 and serves the residential neighborhood along Orchard Circle and Heritage Drive, north of Freedom Drive. The subzone’s slightly lower hydraulic grade requires a dedicated PRS supply from Zone 1220.
Storage Facilities
• This subzone does not have storage facilities. Pressure is provided solely by the PRS connection.
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Supply Sources and System Connections
• Freedom PRS – Supplies water from Zone 1220 to Subzone 1060 Subzone Characteristics
• A small, localized service area dependent entirely on PRS operations. • Residential land use
• Proximity to Zone 1220 pipelines, allowing reliable PRS supply.
A map of Subzone 1060 (Freedom) is included in Figure 2.17.
Figure 2.17 – System Pressure Zone 1060 (Freedom)
2.2.6.3. Subzone 1310 (Mabey Canyon)
Subzone Overview
Pressure Zone 1310 (Mabey Canyon) is located in the foothill area near Mabey Canyon Road. The subzone is bounded by Avenida Del Vista to the north, Border Avenue to the east, and Foothill Parkway to the
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west. The subzone serves a small residential neighborhood requiring a higher hydraulic grade than Zone 1220.
Storage Facilities
• Subzone 1310 does not include dedicated storage; pressures are established through booster pump operations.
Supply Sources and System Connections
• Mabey Canyon Hydro-Pneumatic Pump Station – Lifts water from Zone 1220 to Subzone 1310. • Note: The Mabey Canyon Hydro-Pneumatic Pump Station is expected to be abandoned in the future based on system operational planning.
Subzone Characteristics
• A small hillside residential neighborhood dependent solely on a single booster pump station for supply.
• Lack of storage creates sensitivity to booster pump station downtime. • Future station abandonment will likely require hydraulic realignment or PRS adjustments.
A map of Subzone 1310 is shown in Figure 2.18.
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Figure 2.18 – System Pressure Zone 1310
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2.2.7. Zone 1320
Zone Overview
Pressure Zone 1320 is a small operational zone located near the Temescal Valley Water District (TVWD) service area. Rather than serving a dedicated demand area, Zone 1320 functions primarily as a transfer zone that supports emergency and interagency water exchanges.
Storage Facilities
• Zone 1320 does not include any storage facilities. All operations occur through PRS and pump station movements.
Supply Sources and System Connections
• TVWD-1 PRS – Conveys water from TVWD to City of Corona Zone 1320 • TVWD-2 Pump Station – Conveys water from City of Corona Zone 1320 to TVWD.
Zone Characteristics
• Zone 1320 functions entirely as a bi-directional transfer zone rather than a standard pressure zone.
• Operation is driven by interagency needs, emergency water movement, and mutual aid requirements.
• No local distribution network is present.
Because the subzone only serves as an inter-agency connection, a zone map is not provided.
2.2.8. Zone 1380 and Subzones (Zone 5)
Zone Overview
Pressure Zone 1380 is located in the southern area of the City, south of Zone 1220. The zone serves hillside neighborhoods at elevations ranging from approximately 1,100 to 1,260 feet AMSL. Zone 1380 is a high‐ pressure zone with significant reliance on pumping and dedicated tank storage.
Storage Facilities
• Gilbert Tank – Provides operational and fire storage and establishes the zone’s hydraulic grade. • Eagle Glen Tank – Supplements storage capacity and stabilizes pressures across the southern service area.
Supply Sources and System Connections
• Mills Connection – Transfers water from Zone 1220 to Zone 1380. • Eagle Glen Zone 5 Booster Pump Station – Lifts water from Zone 1220 to Zone 1380. • Lester Zone 5 Booster Pump Station – Lifts water from Zone 1060 to Zone 1380. • Sierra Bella Booster Pump Station – Lifts water from Zone 1060 to Zone 1380.
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• Eagle Glen PRS – Supplies water from Zone 1380 to Zone 1220. • Mountain Gate PRS – Supplies water from Zone 1380 to Zone 1220. • Sierra Bella East/West PRSs – Supply water from Zone 1380 to Zone 1220. • Sonrisa PRS – Supplies water from Zone 1380 to Subzone 1250. • Eagle Glen Zone 6 Booster Pump Station – Lifts water from Zone 1380 to Zone 1640. • Payette Booster Pump Station – Lifts water from Zone 1380 to Zone 1640.
Zone Characteristics
• A high-elevation pressure zone with multiple hillside neighborhoods requiring elevated hydraulic grades.
• Two large storage tanks that support both Zone 1380 and downstream PRS flows. • Multiple PRSs provide controlled pressure step-down to lower adjacent zones.
A map of Zone 1380 is provided in Figure 2.19.
Figure 2.19 – System Pressure Zone 1380
NOTE: The “Hydrant” layer was turned off for this pressure zone, to showcase other GIS attributes.
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2.2.8.1. Subzone 1250 Sonrisa
Subzone Overview
Pressure Zone 1250 (Sonrisa) is situated between Pressure Zones 1220 and 1380 and serves residences along Sonrisa Drive. The subzone occupies a narrow development area requiring a lower hydraulic grade than Zone 1380.
Storage Facilities
• Subzone 1250 does not include any storage facilities.
Supply Sources and System Connections
• Sonrisa PRS – Supplies water from Zone 1380 to Subzone 1250.
Subzone Characteristics
• A linear residential service area located along a single street corridor. • Fully dependent on PRS supply, with no boosting or storage. • Hydraulic grade tailored specifically to avoid excessive pressures from adjacent high-elevation zones.
A map of Subzone 1250 is shown in Figure 2.20.
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Figure 2.20 – System Pressure Zone 1250
2.2.8.2. Subzone 1220 (Montana Ranch)
Subzone Overview
Pressure Zone 1220 (Montana Ranch) is located near the City’s western boundary, in the hillside neighborhoods accessed from Hidden Hills Way and Montana Ranch Road. The subzone is bordered by Hidden Hills Way and Montana Ranch Road to the north and by Green River Road to the east. Montana Ranch requires an elevated hydraulic grade relative to adjacent portions of Zone 1220.
Storage Facilities
• Subzone 1220 does not include dedicated storage; pressures are established through upstream supply facilities.
Supply Sources and System Connections
• Sierra Bella East and West PRSs – Supply water from Zone 1380 to Subzone 1220. • Montana Ranch Hydro-Pneumatic Pump Station – Lifts water from Zone 1060 to Subzone 1220.
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Subzone Characteristics
• A small, isolated hillside neighborhood requiring a lower hydraulic grade. • Redundant supply paths from two separate PRSs and one booster pump station, providing operational reliability.
• No local storage, making PRS and booster pump station performance critical.
A map of Subzone 1220 (Montana Ranch) is provided in Figure 2.21.
Figure 2.21 – System Pressure Zone 1220 (Montana Ranch)
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2.2.9. Zone 1640 and Subzones (Zone 6)
Zone Overview
Pressure Zone 1640 represents the City’s highest operational pressure zone, located in the southernmost portion of Corona, above Zone 1380. The Zone serves elevations above approximately 1,450 feet AMSL and includes steep hillside neighborhoods requiring maximum system hydraulic grade.
Storage Facilities
• Jameson Tank – Provides the controlling hydraulic grade for Zone 1640 and offers both operational and fire storage capacity.
Supply Sources and System Connections
• Payette Booster Pump Station – Lifts water from Zone 1380 to Zone 1640. • Eagle Glen Zone 6 Booster Pump Station – Lifts water from Zone 1380 to Zone 1640. • Orange Heights PRS – Supplies water from Zone 1640 to Subzone 1480.
Zone Characteristics
• The highest-pressure service area in the City requiring robust booster pump station support. • Two independent booster supply paths for the hillside neighborhoods.
A map of Zone 1640 is shown in Figure 2.22.
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Figure 2.22 – System Pressure Zone 1640
2.2.9.1. Subzone 1480 Orange Heights
Subzone Overview
Pressure Zone 1480 (Orange Heights) is a small subzone located within Zone 1640. The subzone serves residents along Orange Heights Lane, generally between Malaga Street and South Main Street.
Storage Facilities
• Subzone 1480 does not include dedicated storage; all pressures are controlled through the upstream PRS.
Supply Sources and System Connections
• Orange Heights PRS – Supplies water from Zone 1640 to Subzone 1480.
Subzone Characteristics
• A compact residential area requiring a reduced hydraulic grade relative to Zone 1640. • Full dependence on PRS operation with no storage or booster facilities.
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• PRS control is essential to avoid over-pressurization due to the high elevation head of Zone 1640.
A map of Subzone 1480 is shown in Figure 2.23.
Figure 2.23 – System Pressure Zone 1480
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2.3. WATER SUPPLY AND TREATMENT FACILITIES
The City’s potable water supply is a combination of groundwater and imported water (treated and untreated). Corona’s groundwater is supplied from wells in two (2) basins: the Temescal Basin and the Bedford-Coldwater Basin. The imported water, both untreated and treated, is from Western Municipal Water District (WMWD). Section 3 contains detailed information about the water supply.
2.3.1. Local Groundwater Supply
The groundwater wells extract groundwater from the Temescal and Bedford-Coldwater Basins. The City operates and maintains a total of twenty-three (23) wells, twenty-one (21) of which are potable water wells, and two (2) are non-potable water wells on the Water Reclamation System. Some wells have been designated as inactive by the State of California Water Resources Control Board Division of Drinking Water (DDW) and are noted in subsequent tables as “inactive” or “standby”. An inactive source is not an approved source of supply and must be physically disconnected or otherwise isolated so that only an intentional act by an operator can place the source into service, and a standby source is an emergency source that is not approved to be used for more than 15 calendar days per year or for periods that exceed 5 consecutive days.
2.3.1.1. Temescal Basin Wells
The City owns and operates eighteen (18) potable water wells in the Temescal Basin, and their locations are shown in Figure 2.24. The Temescal Basin well specifications, construction information, and capacity are presented in Table 2.1, and Table 2.2 summarizes the treatment and storage at each well. Appendix G includes a detailed condition assessment based on the provided well data, record drawings, picture log, and SCE efficiency test.
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Table 2.1 – Temescal Basin Well Inventory and Specifications No. Well
No. Address Status
Well Head
Elevation
(ft)
Depth
(ft)
Pump
Depth
(ft)
Year
Drilled
Maximum
Capacity
(GPM)
Record
Drawing No.
1 7A 917 Circle City Drive Active 680 210 200 2002 1,000 02-088 2 8A 219 S. Joy Street Active 647 210 200 2002 1,650 02-088, 91-012
3 9A 505 S. Vicentia Avenue Active 691 250 240 2002 1,500 02-088 [1] 4 11A 1865 W. Pomona Road Active 650 234 180 1953 700 09-093 5 12A 519 S. Maple Street Active 661 250 180 1949 1,100 43-1299 [1] 6 13 1018 Cottonwood Court Inactive 735 279 160 1952 1,000 Well No. 13 [2] 7 14 1200 W. 10th Street Active 728 515 210 1936 1,000 07-102 97-102
8 15 102 N. Lincoln Avenue Active 640 220 120 1946 [3] 1,100 08-100E 9 17A 1052 Quarry Street Active 648 204 150 1987 1,400 02-089 10 19 219 W. Grand Boulevard Active 630 660 460 1990 2,100 90-036 11 22 405 Sierra Vista Street Active 660 410 370 1998 3,500 99-088 12 25 310 S. Vicentia Avenue Active 648 210 180 1999 3,500 99-088 13 26 710 McGrath Drive Active 578 452 410 1999 1,000 99-088 14 27 2581 Mangular Avenue Active 954 545 480 1980 500 N/A 15 28 202 N. Buena Vista
Avenue Active 610 190 170 2003 2,000 02-088
16 29 240 N. Buena Vista
Avenue Active 602 302 235 2008 N/A 07-083
17 31 210 N. Buena Vista
Avenue Active 639 233 225 2014 N/A 09-110U
18 33 3882 Grant Street Active 666 280 255 2016 N/A 13-038U [1] Refer to as-builts for pipeline connections to the well and the manufacturer's specifications for the well itself. [2] As-built drawing number does not exist; please refer to the building construction plan for a site plan. [3] Well was rehabilitated in 1998.
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Figure 2.24 – Map of Temescal Basin Wells
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Table 2.2 – Temescal Basin Wells Treatment and Storage
Well No. Treatment Storage
7A, 13 (Inactive) Temescal Desalter Garretson Tank (Zone 905) 8A, 17A, 33
Granular Activated Carbon WTP
Garretson Tank (Zone 905)
Temescal Desalter
9A, 19, 22, 25, 26, 28, 29, 31 Temescal Desalter Garretson Tank (Zone 905) 11A, 12A, 14, 15, 27
Routed to Mangular Tank (Zone 905)
for blending Mangular Tank (Zone 905)
Temescal Desalter Garretson Tank (Zone 905)
2.3.1.2. Bedford-Coldwater Basin Wells
The City owns and operates three (3) potable wells and two (2) non-potable wells in the BedfordColdwater Basin, and their locations are shown in Figure 2.25. Appendix G includes a detailed condition assessment based on the provided well data, record drawings, picture log, and SCE efficiency test.
Table 2.3 – Bedford-Coldwater Basin Wells
No. Well
No. Address Status
Well Head
Elevation
(ft)
Depth
(ft)
Pump
Depth
(ft)
Year
Drilled
Maximum
Capacity
(GPM)
Record
Drawing
#
19 3
9865 Glen Ivy
Road Inactive 1138 543 370 1935 1,000 W-200
20 20 25225 Maitri
Road Inactive 1150 660 460 1998 1,650 97-064
21 21 24650 Glen Ivy
Road Inactive 1128 660 460 1998 1,500 97-064
22 NP 1 See Note [1]
23 NP 2 See Note [1]
[1] This is a non-potable well; please refer to the "2018 Reclaimed Water Master Plan" for more information.
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Potable Water Master Plan
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Figure 2.25 – Map of Bedford-Coldwater Basin Wells
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2.3.2. Imported Water Supply, System and Emergency Interconnections, and Emergency Interconnections
The City operates four imported water turnouts and maintains system interconnections and emergency interconnections with neighboring agencies.
2.3.2.1. Imported Water Turnouts
The City’s imported water is supplied by the Metropolitan Water District (MWD) and its member agency, Western Municipal Water District (WMWD). WMWD purchases imported water from MWD, and the City purchases imported water from WMWD. Imported water is delivered to the City through two separate pipelines: the Lower Feeder Pipeline and the Mills Pipeline. • The Lower Feeder Pipeline is part of MWD’s major transmission system and supplies untreated imported water through WMWD.
• The Mills Pipeline is WMWD’s pipeline which delivers treated imported water to portions of Riverside County.
Figure 2.26 depicts the location of the turnouts within the City’s service area.
Table 2.4 – Imported Water Turnouts
Turnout
Name
Turnout
Location
Supply
Location
Elevation
(ft)
Approximate
Hydraulic
Grade
Elevation (ft)
Approximate
Capacity
(gpm)
Service
to
Zones
Description
WR-19
Chase Drive
east of Lester
Avenue
Lester
WTP 945 1,075 13,900 1060
Flow from turnout is gravity
fed to Lester Water
Treatment Plant from Lower
Feeder Pipeline
WR-24
Temescal
Canyon Road
at La Gloria
Road
Lester
WTP 890 1,070 6,300
1060,
1220,
1380
Connected to Mill's Pipeline.
Connection to Bedford
Canyon, Lester, and Tom
Barnes
WR-29
[1] Green River WTP Green River Treatment Plant
is currently inactive
WR-33
1670 Montana
Ranch Road,
west of Green
River Road
Sierra
Del Oro
WTP
940 1,380 4,500 1060
Connected to the Lower
Feeder Pipeline and delivers
untreated water to Sierra
Del Oro Treatment Plant
[1] This turnout is offline due to the inactive Green River Water Treatment Plant. However, it is connected to WMWD's imported water supply via the Lower Feeder Pipeline.
Turnout WR-19. Turnout WR-19 provides imported water from the Lower Feeder Pipeline from WMWD.
The turnout is located on Chase Dr, east of Lester Ave, and the untreated imported water is gravity fed to Lester Water Treatment Plant. The Lester Raw Water Booster Pump Station provides additional pumping head when pressure in the Lower Feeder Pipeline is insufficient for gravity flow to the Lester Water Treatment Plant. The hydraulic grade line of the turnout is typically 1,075 ft above mean sea level (AMSL).
However, it may vary depending on the operation and flow through the turnout.
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Turnout WR-24. Turnout WR-24 provides imported water from the Mill’s Pipeline from WMWD. The turnout is located at Canyon Road and La Gloria Road, and the imported treated water can be delivered to Pressure Zones 1060, 1220, and 1380 through several pressure reducing stations. Corona’s maximum allotment for this turnout is 10 cubic feet per second (cfs).
Turnout WR-29 (Inactive). Turnout WR-29 can provide imported water from the Lower Feeder Pipeline from WMWD, but it is currently inactive. Untreated imported water can be pumped from through the Green River Raw Booster Pump Station to the Green River Water Treatment Plant. The Green River Raw Water Booster Pump Station and the Green River Water Treatment Plant are currently inactive.
Turnout WR-33. Turnout WR-33 provides imported water from the Lower Feeder Pipeline from WMWD.
The turnout is located near Montana Ranch Road, and the untreated imported water is pumped through the Sierra Del Oro Raw Water Booster Pump Station to the Sierra Del Oro Water Treatment Plant. The hydraulic grade line of the turnout is typically at 1070 ft AMSL and may vary depending on the operation and flow through the turnout.
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Potable Water Master Plan
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Figure 2.26 – Map of Imported Water Service Connections
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2.3.2.2. Interconnections
The City maintains interconnections with neighboring agencies: Riverside, the City of Norco, Temescal Valley Water District (TVWD), and Home Gardens County Water District. The Riverside and TVWD interconnections are maintained in case of emergencies (emergency interconnections explained in Section 2.3.2.3. ). A map of the location of the interconnection is provided in Figure 2.27.
Table 2.5 – Interconnections with Neighboring Agencies
Name Location Type of
Interconnection
HGL
Upstream
HGL
Downstream
Treatment
Type
Supply
Location Operability
Approximate
Capacity
(gpm) [2]
Norco 1
Interconnection
NW on
Norco Hills
Rd and
Hidden
Valley Pkwy
Flow Control
Station
Zone
1020
Norco
System Chloramine
Treated
Water from
the City of
Corona [1]
Operable
but not
currently
in use
2,500
Norco 2
Interconnection
2191 Norco
Hills Rd
Flow Control
Station
Zone
1020
Norco
System Chloramine
Treated
Water from
the City of
Corona [1]
Operable
but not
currently
in use
2,500
Home Gardens
Interconnections
3900 S
Temescal St
Flow Control
Station Zone 920
Home
Gardens
System
Chloramine
Treated
Water from
the City of
Corona
Operating
Currently 880
Arlington
Desalter
Interconnection
Promenade
Ave
Pressure
Reducing
Station
WMWD
System 905 Free Chlorine WMWD Operating Currently 3,500 Arlington
Desalter
Interconnection
Promenade
Ave
Pressure
Reducing
Station
1060 WMWD
System Chloramine
Treated
Water from
the City of
Corona
Operating
Currently 3,500
[1] WMWD supplies desalinated brackish water via the Arlington Desalter, which is the City of Norco’s primary source of treated water.
[2] It should be noted that the maximum day flows should not exceed 10 feet per second (fps) and that this approximate capacity is based on this.
Norco 1 and Norco 2. The City of Corona’s Yuma Tank, located in Zone 1020, provides the City of Norco with metered interconnections #1 and #2. In addition, the Norco interconnections could provide reverse flow into the City of Corona in an emergency.
Home Gardens. The unincorporated community of Home Gardens purchases all its water from the City of Corona. The interconnection to Home Gardens is a one-way, metered interconnection.
Arlington Desalter. The Arlington Desalter is owned by WMWD, and the WMWD Arlington Desalter pipeline supplies the City potable water to Zone 905.
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Figure 2.27 – Interconnection with Neighboring Agencies Map
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2.3.2.3. Emergency Interconnections
In the event that the City is unable to supply a portion of its service area due to a catastrophic event within the City, several agreements between the City and neighboring agencies have been made to ensure the City’s users can receive water.
Table 2.6 – Emergency Interconnections
Name Location Type of Interconnection
HGL
Upstream
HGL
Downstream
Treatment
Type
Supply
Location
Approximate
Capacity
(gpm) [3]
Riverside
Emergency
Interconnection 1
Sampson Ave West
of Buchanan St
Normally
Closed Valve 905 925 Chloramine
Treated
Water from
the City of
Corona 1,500
Riverside
Emergency
Interconnection 2
Sampson Ave West
of Buchanan St
Normally
Closed Valve 925 905 Free Chlorine
City of
Riverside
TVWD 1
Emergency
Interconnection [1]
Knabe St North of
Forest Bndy Rd
Pressure
Reducing
Station
1320 1220 Chloramine TVWD 1,500
TVWD 2
Emergency
Interconnection [2]
Temescal Cyn Rd
at Brown Cyn
Wash
Pump Station 1220 1320 Chloramine
Treated
Water from
the City of
Corona
2,500
[1] Please note this emergency interconnection is also a pressure-reducing station and will be accounted for in the Pressure Reducing Station section.
[2] Please note this emergency interconnection is also a pump station and will be accounted for in the Pump Station section. [3] It should be noted that the maximum day flows should not exceed 10 feet per second (fps) and that this approximate capacity is based on this.
City of Riverside. The City of Riverside interconnections are normally closed with the ability to import water to the City of Corona (Interconnection 1) and export water from the City of Corona to the City of Riverside (Interconnection 2).
Temescal Valley Water District (TVWD). TVWD has two (2) interconnections; one for importing water (TVWD 1) and one for exporting (TVWD 2) water. It is important to note that although TVWD 1 and TVWD 2 are emergency interconnections, they are also referred to as pressure-reducing stations and booster pump stations, respectively.
2.3.3. Water Treatment Plants
The City utilizes four active water treatment facilities at locations shown on Figure 2.28 to ensure the quality of its imported surface water and local groundwater meets the state and federal requirements for potable water.
Imported Surface Water Treatment. The Lower Feeder Pipeline provides untreated surface water from WMWD to the City, which is treated by the Lester Water Treatment Plant and the Sierra Del Oro Water Treatment Plant. The Green River Treatment Plant was historically used to treat surface water from the WMWD, but the Green River Water Treatment Plant is currently inactive.
Local Groundwater Treatment. Depending on the location of the well, local groundwater can be treated by the Temescal Desalter or the by the Granular Activated Carbon Water Treatment Plant, see Figure 2.1
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or Section 2.3.2 for additional information. Blending tanks, as described in Section 2.4.1. also support water quality.
Table 2.7 summarizes water treatment facility data, and Appendix F includes more in-depth descriptions of the water treatment facilities including photos. Appendix G includes data, record drawings, picture logs from the 2021 site visit to the water treatment plants.
Table 2.7 – Water Treatment Facilities
No. Water Treatment
Plant Name Address Capacity (MGD) Water Source Constructed Service Zone(s) 1 Sierra Del Oro 2940 Wilderness Circle 6 MWD WR-33 1988 See Note [1] 2 Temescal Desalter 745 Corporation-Yard
Way 10
Groundwater (Well
No.7A, 8A, 9A, 11A,
12A, 13, 14, 15, 17A, 19,
22, 25, 26, 27, 28, 29,
31, & 33)
2002 See Note [2]
3 Lester 2970 Rimpau Ave 30 MWD WR-19
MWD WR-24 1966 See Note [3]
4 Granular
Activated Carbon 410 Rimpau Ave 2 Well 32, 33, 17A, 8A 2019 NA
(Temescal
Desalter
TP) [4]
5 Green River 1400 Nicolas Pl Inactive
[1] Sierra Del Oro’s treated water is stored in the storage tank (4 MG at 1060 HGL). The water from the tank flows directly to Zone 1060. The water is blended and goes through a series of pump stations and pressure-reducing stations to serve other zones.
[2] The Temescal Desalter’s treated water is blended in Garretson Tank. The water from the tank flows directly to Zone 905. The water goes through a series of pump stations and pressure-reducing stations to serve other zones. [3] Lester Water Treatment Plant’s treated water is stored in Lester Tank #1 and Lester Tank #2 (1060 HGL). The water from the tanks flows directly to Zone 1060. The water then goes to Zone 1220 and Zone 1380 by a series of pump stations.
[4] The water from the Granular Activated Carbon Water Treatment Plant goes directly to the Temescal Desalter. Refer to note [2] for further explanation of where the water goes after being treated in the Temescal Desalter.
2.3.3.1. Lester Water Treatment Plant
The City constructed its first treatment facility, Lester Water Treatment Plant, in 1966; and began supplementing local groundwater supplies with imported Colorado River Water. The treatment plant has a total rated capacity of thirty (30) million gallons per day (MGD), producing up to 30% of the City’s demand, and is the largest treatment plant in the City of Corona. It is fed by WMWD’s Colorado River Aqueduct from the Lower Feeder Pipeline through the WR-19 turnout. The treatment plant uses Lester Raw Water Booster Pump Station when the hydraulic grade elevation of the Lower Feeder Pipeline is too low. Please refer to Table 2.7, footnote number 3. Lester Water Treatment Plant treats total suspended solid (TSS) using six (6) filters. The treatment process is as follows:
1. Pre-treatment: Chlorine, aluminum sulfate, and cationic polymer are fed into the static mixer. The aluminum sulfate and cationic polymer act as a coagulant to help the creation of floc. Chlorine dosing will start the disinfection process, prevent the bio-growth from occurring on the filter and pipes, and assist with any taste and odor issues the plant may have.
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2. Coagulation and flocculation: Suspended solids are aggregated to form larger particles called floc.
The purpose of creating floc is to prevent small particles from escaping the filtration system.
3. Filtration: The water passes through the dual media bed of anthracite and sand. The filtration process will capture any floc formed during the flocculation process.
4. Disinfection: The chlorine is injected after combining filter effluent before going to the Chlorine contact basin (CCT). Water flows through CCT for a few minutes to a few hours. Once the water leaves Lester, it is safe to drink and meets all state regulations.
5. Backwash: During backwash, water is pumped backward through the filters to clean particulates and polymers that adhere to the filters. Backwashing is part of routine maintenance that enables near continuous operation.
This plant typically produces 4 to 25 MGD depending on City demand. Hydraulic detention time is 30 minutes to 3 hours, depending on the flow rate. Once water is treated, it is stored in the onsite Lester tank.
2.3.3.2. Sierra Del Oro Water Treatment Plant
The Sierra Del Oro Water Treatment Plant is located on the City's west side and has a total rated capacity of six (6) MGD. However, the facility routinely treats 9.1 MGD during the City’s maximum day conditions from turnout WR-33. The treatment process is as follows:
1. Pretreatment: In the pre-treatment stage, chlorine, aluminum sulfate, and cationic polymers are injected into a static mixer. The aluminum sulfate and cationic polymer act as a coagulant to assist with the formation of floc.
2. Coagulation and flocculation: Floc is created when suspended solids group together to form larger particles, and floc is captured by the filtration system. Generally, the flocculation occurs in the sedimentation basin. Polyethylene balls block UV rays and limit chlorine loss in the sedimentation basins.
3. Sedimentation Basin: In the sedimentation basin, aluminum sulfate and cationic polymer added in pretreatment promote floc formation which results in larger particulates settling. Settled floc and other settled particulates are ranked from the bottom of the sedimentation basin twice per day by the traveling bridges, and the sludge is pumped.
4. Filtration: The water from the sedimentation is gravity fed through the series of three (3) dual media filters consisting of anthracite and sand. These filters remove remaining suspended solids that formed during the flocculation process.
5. Disinfection: Chlorine is added to the filtered water to complete disinfection before it is discharged into the distribution system.
Since the Sierra Del Oro Water Treatment Plant is a conventional treatment plant with sedimentation basins, it has longer detention times and less frequent backwashesthan the Lester Water Treatment Plant.
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2.3.3.3. Green River Treatment Plant (Inactive)
The Green River Treatment Plant is inactive but connected to the MWD Lower Feeder Pipeline via WR-29.
It has a total rated capacity of one (1) MGD and is located on the City's west side.
2.3.3.4. Temescal Desalter Treatment Plant
The Temescal Desalter treats groundwater from the Temescal Basin Wells. The Temescal Basin Wells include the following: Common Well Flow Valve 19 (a portion of flow from Wells 7A, 8A, 13, 17A, 32 and 33), Common Well Flow Valve 22 (a portion of flow from Wells 11A, 12A, 14, 15 and 27), and the Desalter Wells. The Temescal Desalter is a Reverse Osmosis (RO) Treatment Facility where water is forced through a membrane that rejects most dissolved solids. The Temescal Desalter has 1,407 membranes. All the water is prefiltered before it gets to the Desalter to avoid membrane damage. The Temescal Desalter provides high-quality groundwater by removing salts, nitrates, and contaminants. It reduces the City’s dependence on imported surface water by treating local groundwater.
The Temescal Desalter produces 10.4 MGD of treated water, which is transmitted to Garretson Tank and blended with another 4.3 MGD of groundwater that has high concentration of nitrate. Blending of multiple water supply sources at Garretson Tank results in the 14.7 MGD of treated water that meet state and Federal drinking water quality requirements. The Temescal Desalter also generates concentrate byproduct that is discharged into the Inland Empire Brine Line owned and operated by the Santa Ana Watershed Project Authority and transmitted to a brine treatment plant owned and operated by Orange County Sanitary District. The treatment process is as follows:
1. Pre-chemical injection: Sulfuric acid is injected to reduce the pH of the water. Threshold inhibitor is injected to keep a soluble salt in place to prevent fouling membranes.
2. Pre-treatment filters: Four cartridge vessels that contain 176 filters-in-place are designed to remove the larger suspended solids from the water prior to RO filtration.
3. Reverse osmosis filtration: The 201 vessels containing seven reverse osmosis membranes each operate under high pressure. Total dissolved solids are removed through the 1-micron membrane, and the RO filtered water is permeate drinking water.
4. Post-treatment: Four (4) de-carbonators strip Carbon Dioxide (CO2) from the water.
5. Post-chemical injection: The final treatment is sodium hydroxide injection to raise the pH of the water, and chlorine injected with aqueous ammonia to create chloramines for chlorine residuals in the distribution system.
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Potable Water Master Plan
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Figure 2.28 – Map of Treatment Plants
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2.3.3.5. Granular Activated Carbon Water Treatment Plant The City’s Granular Activate Carbon (GAC) Water Treatment Plant serves Zone 1 and has a capacity of 3.45 MGD. In GAC water treatment, the water flows through a bed of GAC granules, and contaminants are adsorbed to the porous carbon material.
The GAC water treatment plant is housed in a metal building, and the treatment process targets removal of 1,2,3-Trichloropropane (TCP) and PFAS/PFOS. The facility was formerly an ion exchange treatment facility at this location.
2.4. STORAGE AND DISTRIBUTION INFRASTRUCTURE
2.4.1. Tanks
The City’s water storage consists of eighteen (18) tanks, including five (5) steel and thirteen (13) concrete, constructed between 1954 and 2019. The tank volumes range from 0.5 million gallons (MG) to 6 MG and are located throughout the City as shown on Figure 2.29. Table 2.8 shows each tank's location, service zone, capacity, high water level (HWL), depth, construction type, year constructed, and As-Built number.
Four water tanks also serve as blending tanks, which are essential for maintaining drinking water quality in accordance with state and federal regulations. The location of each Blending Water Tank is shown in Figure 2.30 and the blending tanks are denoted in Table 2.8.
Appendix G includes a detailed condition assessment based on the provided tank data, record drawings, and picture log.
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Table 2.8 – Tanks
No. Tank Name Address Water Supply Sources
Service
Zone
Capacity
(mg)
HWL
(ft)
Depth
(ft)
Outlet
(in) Construction Type
Year
Constru
cted
As-Built
No.
1 Green River 4130 Green River Rd Green River WTP (inactive) 725 1.5 725 24 18 - 24 Welded Steel 1984 N/A 2 Cresta Verde 2549 Promenade Ave R-3 blend station for the Corona Hills area 905 4.0 905 24 30 Reinforced Concrete 1986 86-02 3 Garretson [1] 2209 E Garretson Ave Temescal Desalter and temescal desalter bypass 905 2.0 905 24 16 - 16 Reinforced Concrete 1978 W-184B 4 Mangular [1] 2208 Mangular Ave
Mangular Blending Cell, primarily
from the West Well; Wells #11A,
#12A, #14, #15, and #27
905 2.0 905 24 16 - 20 Reinforced Concrete 1978 W-184D
5 R-3 2000 Garretson Ave Groundwater wells and Lester WTP 905 2.5 905 19 16 - 20 Reinforced Concrete 2015 W-182S 07-023U
6 Border 2525 Border Ave Glen Ivy Tank, Lester Treatment Plant, and Sierra Del Oro tanks. 1060 3.0 1,020 20 18 -2(12) Reinforced Concrete 1969 W-121 7 Glen Ivy [2]
(Inactive) 8965 Glen Ivy Rd Well 3, 20, and 21 (Inactive) and Lester Tanks 1136 0.5 1,136 23.5 16 - 18 Welded Steel 1977 W-182
W-183CC
8 Lester #1 [1] 2970 Rimpau Ave Lester WTP and blended well water Eastern
areas of
1060
2.0 1,060 24 16 - 24 Reinforced Concrete 1978 W-184A
9 Lester #2 [1] 2970 Rimpau Ave Lester WTP and blended well water Eastern
areas of
1060
2.0 1,060 18 24 - 16 Reinforced Concrete 1995 N/A
10 Sierra Del Oro 2940 Wilderness Cir Sierra Del Oro WTP 1060 4.0 1,060 30 24 - 24 Post Tensioned Concrete 1987 W-347
11 Yuma 881 Corsica Dr Lester Tanks (#1 and #2) and the Cresta Verde Booster Pump Station 1020 6.0 1,020 35 20 Post Tensioned Concrete 1991 89-063U 12 Avenida Del
Vista 2750 Raven Cir Zone 1020 and Border Booster Pump Station 1220 1.6 1,220 31 16 Welded Steel 1977 W-142 13 Hayden 3590 Nelson Ave Zone 1220 1220 1.6 1,220 31 16 Welded Steel 1970 W-118 14 Upper & Main 101 W Upper Dr Lester Zone 4 Booster Pump Station and Zone 1220 1220 4.0 1,220 30 16 Reinforced Concrete 2000 92-01 15 Eagle Glen 1602 Fairway Dr Zone 1380 1380 2.0 1,380 30 16 Welded Steel 1999 98-061U 16 Gilbert 4065 Gilbert Ave Zone 1380 1380 4.7 1,380 30 20 Post Tensioned 1994 US91-03 17 Jameson 4268 Jameson Dr Payette Booster Pump Station 1640 2.5 1,640 29.6 16 Post Tensioned Concrete 2005 05-078U
18 Keith 3985 Nelson St Zone 1220 1220 2.5 1,220 33 16 Reinforced Concrete 2019 17-052U [1] Blending Water Tank
[2] Scheduled for demolition
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Potable Water Master Plan
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Figure 2.29 – Map of Tanks
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Potable Water Master Plan
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Figure 2.30 – Map of Blending Stations
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Potable Water Master Plan
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2.4.2. Booster Pump Stations
The City’s twenty (20) pump stations deliver groundwater from wells to the system tanks, lift water from lower pressure zones to higher pressure zones, and lift imported water from the MWD Colorado River transmission lines to the treatment plants. The City has both booster pump stations and hydro-pneumatic pump stations. The Pump Stations’ general data, pump data, and motor data are listed in Table 2.9 and additional motor information is listed. Appendix G includes a detailed condition assessment based on the provided pump data, record drawings, picture log, and SCE efficiency test.
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Table 2.9 – Booster Pump Stations
General Data Pump Data Motor Data
No
Suction
Zone
Discha
rge
Zone
Name Location Suction
Tank
Discharg
e Tank
Type of
PS
Pump
No.
Type
of
Pump
GPM TDH
(ft) HP RPM
1 725 1060 Green River
(standby)
1400
Nicholas Pl
Green
River SDO Booster 1 Horz. 850 341 125 1775
2 905 1020 Cresta
Verde
2005
Promenad
e Avenue
Cresta
Verde Yuma Booster
1 Vert. 1,350 128 60 1785
2 Vert. 1,350 128 60 1785
3 Vert. 1,350 128 60 1785
4-fire Vert. 1,350 128 60 1785
3 905 1060 Garretson
Zone 3
2209
Garretson
Avenue
Garretson Lester 1
& 2 Booster
1 Vert. 2,500 229 200 1785
2 Vert. 2,500 229 200 1785
3 Vert. 2,500 229 200 1785
4 Vert. 2,500 229 200 1785
5 Vert. 2,500 190 200 1785
6 Vert. 2,500 229 200 1785
4 905 1060 Serfas Club
1290
Serfas Club
Dr
Mangular SDO Booster
1 Vert. 1,500 282 150 1790
2-spare
[4]
-
- - - -
5 905 1060 &
1220 Mangular [2]
2208
Mangular
Ave
Mangular
SDO or
Lester 1
& 2
Booster
1-Z3 [3] Vert. 2,500 190 150 1785
2-Z3 [3]
Vert. 2,500 190 150 1785
1- Z4 [3]
Vert. 1,250 366 150 1785
2-Z4 [3]
Vert. 1,250 366 150 1785
3-Z4 [3] Vert. 1,250 366 150 1785
6 905 1220 Garretson
Zone 4
2209
Garretson
Avenue
Garretson
All Zone
4 Reservoir
s
Booster
1 Vert. 1,250 392 200 1785
2 Vert. 1,250 392 200 1785
3 Vert. 1,250 392 200 1785
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Potable Water Master Plan
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Table 2.9 – Booster Pump Stations
General Data Pump Data Motor Data
No
Suction
Zone
Discha
rge
Zone
Name Location Suction
Tank
Discharg
e Tank
Type of
PS
Pump
No.
Type
of
Pump
GPM TDH
(ft) HP RPM
7 1020 1235 Morita 755 Morita
Dr
Cresta
Verde Sub Zone
HydroPneumati
c
1 Vert. 500 259 50 1790
2 Vert. 500 259 50 1790
3-fire Vert. 1,500 200 100 1790
8 1020 1130 Aquino 1036
Aquino Ci Yuma Sub Zone
HydroPneumati
c
1 Horz. 150 93 7.5 3450
2 Horz. 150 93 7.5 3450
9 1060 1220 Border
Border
Ave, N/W
Corner of
Border Ave
& Ontario
Ave
Border Avenida
Del Vista Booster
1 Vert. 400 220 30 1800
2 Vert. 1,200 220 100 1770
3 Vert. 900 220 75 1770
10 1060 1220 Chase
1315
Chase Dr,
N/E Corner
of Chase
Dr &
Rimpau
Ave
Lester 1 &
2 Hayden Booster
1 Vert. 800 236 60 1775
2 Vert. 800 235 60 1770
3 Vert. 900 185 60 1800
4 Vert. 1500 250 125 1785
11 1060 1220 Lester Zone
4 [1]
2970
Rimpau
Ave
Lester 1 &
2 Upper &
Main Booster
1 Vert. 1,600 180 100 1800
2 Vert. 1,600 180 100 1800
3 Vert. 1,600 180 100 1750
4 Vert. 1,600 180 100 1750
12 1060 1220 Montana
Ranch
2930
Wilderness
Circle
SDO Sub Zone
HydroPneumati
c
1 Vert. 375 173 25 1770
2 Vert. 375 173 25 1770
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Table 2.9 – Booster Pump Stations
General Data Pump Data Motor Data
No
Suction
Zone
Discha
rge
Zone
Name Location Suction
Tank
Discharg
e Tank
Type of
PS
Pump
No.
Type
of
Pump
GPM TDH
(ft) HP RPM
13 1060 1315 Kraft Ranch
1725
Oakridge
Dr
SDO Sub Zone
HydroPneumati
c
1 Vert. 600 260 50 1780
2 Vert. 600 260 50 1780
3-fire Vert. 1,500 240 125 1785
14 1060 1380 Lester Zone
5 [1]
2970
Rimpau
Avenue
Lester 1 &
2 Gilbert Booster
1 Vert. 1,365 354 200 1786
2 Vert. 1,365 354 200 1786
3 Vert. 1,365 354 200 1785
4 Vert. 1,365 354 200 1786
5 Vert. 1,365 354 200 1785
15 1220 1380 Eagle Glen
Zone 5
4255 Eagle
Glen Pkwy Hayden Eagle Glen Booster
1 [1] Horz. 800 190 60 1775
2 Horz. 800 190 60 1775
16 1220 1380 Harlan Hills
S/W
Corner of
Bonnyview
Ci &
Lindsey Ln
Avenida
Del Vista Sub Zone Booster
1 Vert. 230 90 10 1760
2 Vert. 230 90 10 1760
3-fire Vert. 1,500 130 75 1780
17 1220 1310 Mabey
Canyon
2643
Border Ave
Avenida
Del Vista Sub Zone
HydroPneumati
c
1 Vert. 1,250 125 50 1765
2 Vert. 1,250 125 50 1765
3-fire Horz. 1,500 144 90 1770
18 1380 1640 Eagle Glen
Zone 6
1602
Fairway Dr Eagle Glen Jameson Booster
1 Vert. 230 270 25 1770
2 Vert. 236 270 25 1770
3 Vert. 230 270 25 1770
4-fire Vert. 1,500 266 150 1780
19 1380 1640 Payette 881
Payette Dr Gilbert Jameson Booster
1 Vert. 750 273 75 1780
2 Vert. 750 273 75 1780
3 Vert. 750 273 75 1780
4 Vert. 750 273 75 1780
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Table 2.9 – Booster Pump Stations
General Data Pump Data Motor Data
No
Suction
Zone
Discha
rge
Zone
Name Location Suction
Tank
Discharg
e Tank
Type of
PS
Pump
No.
Type
of
Pump
GPM TDH
(ft) HP RPM
20 1060 1380 Sierra Bella
2690
Hidden
Hills Way
West
Lester 1 &
2 Eagle
Glen Booster
1 Vert. 1,500 338 200 1785
2 Vert. 1,500 338 200 1785
[1] The booster pump station is part of a treatment plant [2] If water is blending at Lester, then the discharge reservoir is Sierra Del Oro (SDO). If water is blending at SDO, then the discharge reservoir is Lester 1 & 2. [3] Pumps at this booster pump station discharge to two zones: Zone 1060 (Z3) and Zone 1220 (Z4). [4] Spare pump denotes an unequipped pump can.
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Figure 2.31 – Map of Booster Pump Stations
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2.4.3. Pressure Reducing Stations
The City’s thirty-two (32) pressure reducing stations (PRS’s) transfer water from higher-pressure zones to lower-pressure zones while maintaining the pressure in each zone. Proper maintenance of these facilities is critically important to the pressure maintenance within each City’s pressure zone. Figure 2.32 shows a map of these facilities within the City’s service area. Appendix G includes a detailed condition assessment based on the provided PRS data, and picture log.
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Table 2.10 – Pressure Reducing Stations
No Name Location Elevation
(ft)
D/S
Zone
U/S HGL
(elev)
D/S HGL
(elev) Valve Size D/S Pressure Settings (psi)
U/S Pressure
Settings (psi)
1 North Smith N Smith St. & Railroad St. 575 780 905
749 4-inch 88 140 722 8-inch 80
763 4-inch 100 Atmo
2 Kalus River Rd., Btw Samar Ct. & Kalus
Ave. 589 780 905
750 4-inch 78 128 723 8-inch 70
797 4-inch 90 Atmo
3 Alcoa W Rincon St. & Alcoa Ci. 574 780 905
763 4-inch 82 135-140 740 8-inch 72
787 4-inch 92 Atmo
4 Harrington Harrington St & Windstream St 592 780 905 795/781 4-inch 88-82 130 8-inch 88-72 800 4-inch 90 Atmo
5 Dominguez
Ranch SW of Dominguez and Green River 515 725 905
N/A 4-inch N/A 160 N/A 8-inch N/A
973 4-inch 95 Atmo/100
6 Auto Center Drive Railroad St. & Auto Center Dr. 576 820 905 779 4-inch 88 135 761 8-inch 80
807 4-inch 100 Atmo
7 Yorba 125 Klug Ci, Railroad St. & Klug Ci. 595 820 905 768 4-inch 75 130 752 8-inch 68
821 4-inch 98 Atmo
8 South Smith N Smith Ave, Btw Railroad St & W
Maple St. 590 820 905
775 4-inch 80 130 756 8-inch 72
821 4-inch 100 Atmo
9 Avenida Del Vista Avenida Del Vista & Via Del Rio 755 905 1060 871 6-inch 50 125 10 Mt. Serenata Dominguez Ranch Rd. & Mount
Serenata Ci. 754 905 1060
883 4-inch 56 140 865 8-inch 48
930 4-inch 76 Atmo
11 Green River Green River Rd. & Kraemer Dr. 760 905 1060 889 4-inch 56
127 871 8-inch 48
922 4-inch 70 Atmo
12 Ridgeline Ridgeline Dr, Btw Bayberry Dr. &
Silkwood Dr. 760 905 1060
894 4-inch 58 130 876 8-inch 50
922 4-inch 70 Atmo
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Table 2.10 – Pressure Reducing Stations
No Name Location Elevation
(ft)
D/S
Zone
U/S HGL
(elev)
D/S HGL
(elev) Valve Size D/S Pressure Settings (psi)
U/S Pressure
Settings (psi)
13 San Ponte San Almada Rd. & San Ponte Rd. 764 905 1060 868 4-inch 45 130
856 8-inch 40 140
896 4-inch 57 Atmo
14 Village Loop Hidden Valley Py. & Village Loop
Dr. 761 905 1020
893 4-inch 57 109 877 8-inch 50
911 4-inch 65 Atmo
15 Hummingbird Ontario Ave & Paseo Grand 776 960 1060
905 4-inch 85 110 905 8-inch 85
905 4-inch 150 Atmo
16 Arcadia
(to be
decommissioned)
Arcadia St. & Jolora Ave. 892 1045 1220
1061 1-inch 60 105
N/A 2-inch 60 Atmo
17 West Temescal
Canyon
Temescal Canyon Rd. & Dos Lagos
Dr. 862 1136 1220
1174 [¹] 6-inch [¹]135 [¹]
120 [¹]
1116 [¹] 12-inch [¹] 110 [¹]
1185 6-inch 140 Atmo
18 Freedom Freedom Dr. & Orchard Ln 930 1060 1220
1063 4-inch 60 124
1045 8-inch 52
1098 4-inch 75 Atmo
19 El Cerrito El Cerrito Rd. & Interstate 15 954 1060 1220 1100 4-inch 63
115 1083 8-inch 56
1132 4-inch 77 Atmo
20 Liberty Liberty Ave. & Washington St. 956 1060 1220
1129 4-inch 75 120
1111 8-inch 67
1164 6-inch 90 Atmo
21 Cajalco Temescal Canyon Rd. & Cajalco Rd. 816 1136 1220 992 3-inch 76 181 1024 10-inch 90
1105 4-inch 125 Atmo
22 East Temescal
Canyon
Temescal Canyon Rd. & Dos Lagos
Dr. 860 1136 1220
1190 6-inch 118 154 1190 12-inch 118
1190 6-inch 128 Atmo
23 Eagle Glen 4255 Eagle Glen Parkway 1132 1220 1380
-- 4-inch N/A 30
-- 8-inch N/A
N/A 5-inch -- Atmo
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Table 2.10 – Pressure Reducing Stations
No Name Location Elevation
(ft)
D/S
Zone
U/S HGL
(elev)
D/S HGL
(elev) Valve Size D/S Pressure Settings (psi)
U/S Pressure
Settings (psi)
24 Mountain Gate Mountain Gate Dr. & Upper Dr. 1135 1220 1380 1216 4-inch 35 95 1204 8-inch 30
1238 4-inch 45 Atmo
25 Sonrisa Pacific Rd. & Sonrisa Dr. 1132 1250 1380 1259 2-inch 55 No Gauge 1248 6-inch 50 No Gauge
26 Orange Heights S Main St. & W Orange Heights Ln. 1250 1480 1640 1479 4-inch 100 105 1447 8-inch 86 105
27 White Mountain Valencia Rd. & White Mountain Ci. 1290 1380 1640 1526 4-inch 102 160
1498 8-inch 90 160
1673 4-inch 166 Atmo
28 Main & Olive 1301 S. Main St. Out of Service 4-inch 50 125 6-inch 42 125
29 Magnolia Magnolia and Leeson 754 920 1060
886 [1] 10-inch 57 140
860 [1] 8-inch 46 140
915 [1] 6-inch 70 Atmo
31 Sierra Bella (East) Sierra Bella Dr. & Pele Wy. 1011 1220 1380 1225 4-inch 93 N/A 1190 8-inch 78 N/A
32 Sierra Bella
(West) 2700 Hidden Hills Way N/A 1220 1380 1238 4-inch 80 N/A 1220 8-inch 72 N/A
[1] Values calculated and not field measured.
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Figure 2.32 – Map of Pressure-Reducing Stations
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2.4.4. Flow Control Valve
The City’s fifteen (15) flow control valves (FCV) regulate the flow of water by maintaining desired flow rates to balance system pressure. Table 2.11 shows each of the City’s flow control stations, the status, elevation, upstream and downstream HGL, the flow control valves, and the valve size. Figure 2.33 shows a map of these facilities within the City’s service area. Appendix G includes a detailed condition assessment based on the provided FCV data, and picture log.
Table 2.11 – Flow Control Valves
No Name Location Status Elevation ft D/S HGL
U/S
HGL
Model
Name
Size
1 Dominguez
Ranch
Green River Road and
Dominguez Ranch Road
In
Service
516 725 905 CLA- VAL 8-inch
2 Garretson
Zone 3
Ontario Ave and Magnolia
Ave
In
Service
916 905 1060 CLA- VAL 12-inch
3 Garretson
Zone 2
E Ontario Ave and
Magnolia Ave
In
Service
910 905 1060 CLA- VAL 16-inch
4 Mangular
Blend
Ontario Ave and
Mangular Ave
In
Service
900 905 1060 CLA- VAL 10-inch
5 R-3
Garretson Ave, between
Monterey Rd and Beatrice
Dr
Out of
Service
880 905 1060 CLA- VAL 10-inch
6 Eagle Glen
Vandagriff Way and
Fairway Drive intersection
In
Service
1,132 1220 1380 CLA-VAL 8-inch
7 Lester
Zone 5
Eagle Glen Parkway and
Bedford Canyon Rd
In
Service
930 1380 1500 Flowserve 16-inch
8 Lester
Zone 4
Eagle Glen Parkway and
Bedford Canyon Rd
In
Service
930 1220 1500 Limitorque 12-inch
9 Lester
Zone 3
Eagle Glen Parkway and
Bedford Canyon Rd
In
Service
930 1060 1500 Bayley 12-inch
10 Nicholas
Green River Rd and
Nicholas Plaza
In
Service
708 725 1060 CLA- VAL 8-inch
11 Bedford
Canyon
Eagle Glen Parkway and
Bedford Canyon Rd
In
Service
930 1380 1500 CLA- VAL 4-inch
12 Promenade
Park
Promenade Ave and Ruth
Circle
In
Service
N/A N/A N/A N/A 12-inch
13 CW22 @
Well 22
5 th St and Sierra Vista
In
Service
N/A N/A N/A N/A 8-inch
14 Sampson
FCS [1]
Corporate Terrace St and
Sampson Ave
In
Service
643
Vary
between
905 and
1020
1060 CLA-VAL 12-inch
15 Home
Gardens
Temescal St and Estelle St
In
Service
N/A Home
Gardens
920 CLA-VAL 6-inch
[1] The Sampson facility is classified as a flow control station. When supplying pressure zone 1020, the facility also performs a pressure-reducing function.
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Figure 2.33 – Map of Flow Control Stations
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2.4.5. Water Transmission and Distribution Pipelines
The City has approximately 675 miles of water distribution pipelines within the service area. The water pipelines transmit the water to reservoirs and water treatment plants and distribute water across the City to all of Corona’s potable water system users. Each pipeline has unique attributes including length, materials, diameters, and flow. Table 2.12 lists total length of each pipe diameter, and Figure 2.34 maps pipeline diameters within the City. This section bases the pipeline inventory summary on GIS data provided in November 2021.
Pipelines range from 1-inch to 36 inches diameter with approximately 45% of the system as 8-inch and approximately 12% of the system as 12-inch diameter. Pipelines smaller than 8 inches were constructed before the City adopted a minimum 8-inch diameter water distribution pipeline size and will be replaced with 8-inch diameter pipelines when the pipelines have reached the end of their service life. Pipelines 12 inches or smaller are classified as distribution pipelines, and pipelines 14-inch or larger are classified as transmission lines.
Table 2.12 – 2021 City of Corona Water Pipelines Inventory Size (in) Length (ft)
(%) of Total Water
Distribution System
1 451 0.01%
1.25 51 0.00%
1.5 439 0.01%
2 27,271 0.77%
2.5 2,918 0.08%
3 3,433 0.10%
4 89,717 2.52%
6 426,751 11.97%
8 1,615,731 45.34%
10 341,608 9.58%
12 537,372 15.08%
14 34,481 0.97%
16 198,300 5.56%
18 38,146 1.07%
20 57,085 1.60%
22 7,540 0.21%
24 87,497 2.46%
27 11,802 0.33%
30 79,059 2.22%
36 4,035 0.11%
Total 3,563,698 100%
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Figure 2.34 – Transmission/Distribution Pipelines
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2.4.5.1. Transmission Pipelines
Transmission pipelines are arteries that move water through the City and range from 14 to 36 inches in diameter. Table 2.13 liststhe City’s transmission pipeline by diameter. In 2021, the City had 457,343 linear feet (95 miles) of transmission pipeline which accounts for 13.74% of the City’s pipelines.
Table 2.13 – 2021 Transmission Pipeline Inventory
Pipe Diameter (in) Length (ft) % of Total Distribution
Pipelines
14 34,481 0.97%
16 198,300 5.56%
18 38,146 1.07%
20 57,085 1.60%
22 7,540 0.21%
24 87,497 2.46%
27 11,802 0.33%
30 79,059 2.22%
36 4,035 0.11%
Total 517,946 14.53%
2.4.5.2. Distribution Pipelines
Distribution pipelines are 12-inch diameter or less and deliver water to communities and neighborhoods within each pressure zone. Table 2.14 lists of the City’s distribution pipeline by diameter. In 2021, the City had 3,024,320 linear feet (572.8 miles) of distribution pipeline which accounts for 85.8% of the City’s pipelines. 45% of the City’s pipelines are 8-inch diameter. As of 2021, the City had 529,547 linear feet (100.3 miles) of pipeline below 8 inches which need to be replaced with 8-inch diameter pipelines at the end of their service life.
Table 2.14 – 2021 Distribution Pipelines Inventory
Pipe
Diameter
(in)
Length (ft) % of Total
Pipelines
1 451 0.01%
1.25 51 0.00%
1.5 439 0.01%
2 27,271 0.77%
2.5 2,918 0.08%
3 3,433 0.10%
4 89,717 2.52%
6 426,751 11.97%
8 1,615,731 45.34%
10 341,608 9.58%
12 537,372 15.08%
Total 3,045,753 85.47%
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2.5. WATER SYSTEM CONTROL AND SAFETY COMPONENTS
The potable water system inventory presented in this section is based on GIS data provided by the City in November 2021. All quantities and asset summaries reflect system conditions as of that date.
2.5.1. Blow-Off Valves
Blow-off valves allow for flushing of water for maintenance and to sample and maintain water quality.
Table 2.15 lists the number of blow-off valves and corresponding sizes captured in the City’s GIS database in 2021. In 2021, the City had 397 blow-off valves, of which 89% were 2 inches in nominal size, and approximately 10% of the blow-off valves had unspecified size attribute data.
Table 2.15 – 2021 Blow-Off Valve Inventory
Valve Size
(in)
Number of
Blowoff Valves
1 2
2 355
3 1
4 1
6 5
8 1
Unspecified 32
Total 397
2.5.2. Air Relief Valves & Combination Valves
Air relief and combination valves release trapped air within the potable water system to maintain uninterrupted water flow within the pipeline. Table 2.16 lists the number of air relief valves and combination valves captured in the City’s GIS database in 2021. As of 2021, the City had 1,067 air relief and combination valves; 71% of which were 1-inch and 2-inches, and approximately 19% of the air relief and combination valves had unspecified size attribute data.
Table 2.16 – 2021 Air Relief & Combination Valve Inventory Valve Size (in)
Number of Air
Relief Valves &
Combination Valves
1 496
1 1/2 2
2 263
3 11
4 and larger 99
Unspecified 197
Total 1,067
2.5.3. Detector Check & Backflow Control Valves
Detector check valves and backflow control valves prevent reverse flow into the potable water system.
Detector check valves are specific to prevent backflow from a fire suppression system, and backflow
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control valves prevent backflow from risk of cross-connection. Table 2.17 lists the City’s detector check & backflow control valves captured in the City’s GIS database in 2021. As of 2021, 61% of the detector check and backflow control valves had unspecified size attribute data.
Table 2.17 – 2021 Detector Check & Backflow Control Valve Inventory Size (in)
Number of Detector
Check Valves
3/4 2
2 3
4 63
6 127
8 194
10 30
Unspecified 726
Total 1,145
2.5.4. Water System Valves
Main valves, zone valves, and fire hydrant valves control water flow within the distribution network and isolate sections for maintenance or firefighting. The main valves, zone valves, and fire hydrant valves are distinct from previously discussed valves that serve other functions like pressure management, air release, and backflow prevention.
2.5.4.1. Main Valves
In 2021, the City had 11,522 main valves throughout its potable water distribution system. Table 2.18 lists the main valves and their sizes captured in the City’s GIS database in 2021. The 8-inch valves represent 48% of the total main valves. 81% of the main valves were between 6 to 12 inches in size; however, approximately 10% of the City’s main valves had unspecified size attribute data.
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Table 2.18 – 2021 Main Valves Inventory
Size (in)
Number of
Main Valves
1 6
1.25 1
1.5 7
2 105
2.5 30
4 218
6 1,176
8 5,603
10 1,066
12 1,461
14 50
16 355
18 29
20 77
24 75
27 4
30 38
36 2
Unspecified 1,219
Total 11,522
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2.5.4.2. Zone Valves
Zone valves assist in controlling the pressures within the City’s potable water supply systems and can be further classified as Zone Butterfly or Zone Gate Valves. In 2021, the City’s potable water supply system had 147 zone valves, specifically 28 zone butterfly valves and 119 zone gate valves. Table 2.19 lists the valve sizes for each of the valve types captured in the City’s GIS database in 2021.
Table 2.19 – 2021 Zone Valves Inventory
Size Zone Butterfly Zone Gate
1 0 0
2 0 0
2.5 0 0
4 0 4
6 5 11
8 6 53
10 6 19
12 4 23
14 0 1
16 1 3
18 0 1
20 0 0
24 4 3
27 0 0
30 2 0
36 0 0
Unspecified 0 1
Total 28 119
2.5.4.3. Fire Hydrant Valves
Fire hydrant valves control the flow of water from the water pipeline to the fire hydrant, and the location of the fire hydrant valve varies based on the type of hydrant. In the City’s GIS database from 2021, only approximately 1% of the fire hydrant valve sizes were captured.
2.5.5. Fire Hydrant Connections
Table 2.20 shows the number of fire hydrants connected to various pipeline diameters as captured in the City’s GIS database in 2021.
The lowest required fire flow for residential communities is 1,500 gpm (1,000 gpm for county areas).
However, several fire hydrants were placed before this requirement was set. At 1,100 locations, the City’s 2021 GIS database includes fire hydrants without specifying the diameter of the pipeline.
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Table 2.20 – 2021 Fire Hydrant Connection Inventory
Diameter of
Pipeline (in)
Number of
Hydrants
4 5
6 1,037
8 4,549
10 891
12 1,001
14 71
16 291
18 41
20 258
22 5
24 91
Unspecified 1,110
Total 9,350
2.6. CUSTOMER SERVICES
2.6.1. Water Meters
In November 2021, the City had 45,863 water meters within the water service area. Table 2.21 shows the sizes and number of meters captured in the City’s GIS database in November 2021. More than 50% of the City’s meters are 3/4-inch, which are predominantly for single-family residential units. Larger meters are used for high-density residential, commercial, and industrial users.
Table 2.21 – 2021 Water Meter Inventory
Meter Size Number of Meters
5/8" 6,860
3/4" 28,797
1" 6,873
1-1/2 1,266
2" 1,772
3" 160
4" 57
6" 37
8" 41
Total 45,863
2.6.2. Service Valves
Service valves are installed on the potable water distribution system to allow servicing and/or disconnection of potable water meters. The service valves can be turned off during construction or maintenance or to prevent water losses if service is compromised at the user’s property due to water leakage, theft, or delinquent payments. It is assumed that each water meter has a service valve.
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2.7. INFRASTRUCTURE CONDITION AND RELIABILITY ANALYSIS
The condition and reliability of the existing infrastructure was evaluated through desktop analysis and WTP site visits described below.
• Desktop analysis of asset database including elements of the NEXGEN Enterprise Asset Management System and available SCADA data.
o Existing GIS asset registers, inventories(including spatial location and attributes of assets) of all physical assets owned or managed by the City, developed prior to the Potable Water System Master Plan were evaluated.
• Site visit to four water treatment plants including photo log documentation of asset condition.
2.7.1. Condition and Reliability Analysis
The specific tasks executed to evaluate facility reliability for the potable water system infrastructure were as follows:
• Review City of Corona GIS inventory of facilities and map asset location based on available data. • Review of the available as-built or other engineering drawings and specifications of the water supply
• Visual inspections of above-ground or visible assets as summarized in Appendix F and Appendix G • Interview City maintenance and planning staff familiar with the construction activities and historic system knowledge.
2.7.1.1. Asset Age Assessment
The City’s groundwater production wells, water treatment plants, storage tanks, pump stations, pressure reducing stations, and pipelines assessment are primarily based around a remaining service life analysis.
The remaining service life analysis considers the age of the asset and the typical service life to determine the need for rehabilitation or replacement.
2.7.2. Groundwater Production Well Analysis
Pump Efficiency. Pump efficiency is a predictive indicator of the likelihood of mechanical and/or electrical equipment failures at production wells. Low efficiencies are indicative of aged and worn equipment, which is more likely to fail, whereas high efficiencies are indicative of newer and/or good condition equipment.
As pump efficiency decreases, the pumping capacity may decrease and impact the City’s ability to produce planned capacity.
SoCal Edison (SCE) efficiency tests determine pump efficiency. • Five (5) wells (Well 27, 31, 33, Non-potable (NP) Well 1 and NP Well 2) have no SCE information. • Four (4) wells (Wells 14, 15, 29 and 31) have recently been replaced or rehabilitated and are assumed to operate above 60% efficiency.
• Five (5) wells (Wells 9A, 8A, 11A, 12A and 28) operate above 60%.
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• Seven (7) wells (Wells 3, 7A, 17A, 20, 21, 22, and 25) operate between 50%-60% efficiency. • Three (3) wells (Wells 13, 19, and 26) operate below 50%.
Pumps operating between 50% and 60% efficiency are an acceptable efficiency range but indicate that mechanical and electrical equipment may degrade and should be considered for replacement or rehabilitation. Any pumps operating below 50% efficiency require replacement of the mechanical and electrical equipment.
Casing. The age and material of the well casing is predictive of useful service life of the casing to preserve structural, seal, and condition integrity. Carbon steel well casings, both low carbon steel and high strength low alloy (HSLA) carbon steel, were installed until the late 1990s, and stainless steel well casings were installed after the late 1990s. The average service life of carbon steel wells is 25 years, and the average service life of stainless steel well casings is 75 years.
Figure 2.35 summarizes well age in 2026 and denotes well casing material.
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Figure 2.35 – Age of Groundwater Production Wells in 2026 and Casing Material 91 90
80 77
74 73
46 44
39 36
28 28 28 27 27
24 24 24 23
18 18
12 8
7 0
5 10
15 20
25 30
35 40
45 50
55 60
65 70
75 80
85 90
95 Age (Years)
Stainless Steel
Carbon Steel
Inactive Well
Stainless Steel
Typical Service Life
High Strength Low Alloy Steel
Low Carbon Steel Page 1242 of 3356
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• As of 2026, all carbon steel wells exceeded their expected service life. Wells 13 and 20 are inactive, and Wells 3 and 21 are standby wells.
Boreholes. Boreholes should be inspected for any wells scheduled for casing rehabilitation. A thorough boring hole inspection is required to determine if the well requires redrilling or relocation.
2.7.3. Water Treatment Plant Analysis
Appendix F summarizes findings from 2021 site visits to the Lester Water Treatment Plant, the Sierra Del Oro Water Treatment Plant, the Temescal Desalter, and the GAC Water Treatment Plant. The condition of the water treatment plant assets was analyzed by visually inspecting plant components and documenting discussions with City operations staff. Figure 2.36 is provided for reference to present the approximate age of the City’s water treatment plant facilities.
More detailed evaluation studies could be completed to analyze assets within the water treatment plants.
Figure 2.36 – Age of Water Treatment Plants in 2026
60 38
24 7
0 10
20 30
40 50
60 70
Lester WTP Sierra Del Oro WTP Temescal Desalter Granular Activated Carbon WTP Age (Years)
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2.7.4. Storage Tank Analysis
Storage tanks should be inspected every three (3) to five (5) years for asset management purposes.
Routine inspection, cleaning, and recoating can prolong the service life of tanks and should be prioritized as part of a maintenance budget.
Tank Material. The City owns and operates five steel tanks and thirteen concrete tanks constructed between 1954 and 2019. Tank material and typical service life alone do not indicate the need to replace a tank. The typical service life for a steel tank is 50 years. Visual inspections in 2021 determined Hayden Tank was in good condition with no signs of corrosion, exceeding 50 years of service life. The Avenida Del Vista and Green Riversteel tanks will exceed the 50-year typical service life by 2040, and the Glen Ivy tank has been removed from service. The typical service life for a concrete tank is 100 years, and the first concrete tank to reach the typical service life will be Border Tank in 2069. Unless an inspection finds damage, none of the City’s concrete tanks will be considered a high risk of failure.
Figure 2.37 reflects that the R-3 tank was reconstructed in 2015.
Figure 2.37 – Age of Storage Tanks in 2026
40 48 48
11 57
48 31
39 35
26 32
21 7
42 49 49
56 27
0 10
20 30
40 50
60 Age (Years)
Concrete Tank
Welded Steel Tank
Welded Steel Typ Service Life
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2.7.5. Pump Station Analysis
As of 2026, most of the City’s pump stations are between 20 and 40 years old. Typical service life on pumping electrical and mechanical equipment is approximately 20 years.
Pump Efficiency. Pump efficiency is a predictive indicator of the likelihood of mechanical and/or electrical equipment failures at production wells. Low efficiencies are indicative of aged and worn equipment, which is more likely to fail, whereas high efficiencies are indicative of newer and/or good condition equipment.
As pump efficiency decreases, the pumping capacity may decrease and impact the City’s ability to produce planned capacity.
SoCal Edison (SCE) efficiency tests determine pump efficiency. • One (1) pump station (Sierra Bella) has no SCE information. • 17 pump stations (Stations Green River, Serfas Club, Lester Zone 4, Lester Zone 5, Garretson, Chase, Garretson Zone 4, Mangular, Border, Cresta Verde, Eagle Glen Zone 6, Payette, Montana Ranch, Kraft Ranch, Harlan Hills, Morita, and Mabey Canyon) operate above 60% efficiency. • Two (2) pump stations (Eagle Glen Zone 5 and Aquino) operate below 50% efficiency.
Pumps operating between 50% and 60% efficiency are an acceptable efficiency range but indicate that mechanical and electrical equipment may degrade and should be considered for replacement or rehabilitation. Any pumps operating below 50% efficiency require replacement of the mechanical and electrical equipment.
Pump Age. Figure 2.38 shows the average age of each pump station in 2026 and associated service lives.
Wet Wells or Pump Vaults. Concrete structures are typically expected to outlive rotating mechanical equipment, but concrete structures require inspection and maintenance. Typical service life of a concrete structure is approximately 50 years. The Chase Pump Station and Border Pump Station structures have exceeded their service life. However, these structures could last longer if they are well maintained. If the structures begin to show signs of degradation, the structures should be replaced.
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Figure 2.38 – Age of Pump Stations in 2026
2.7.6. Pressure Reducing Station Analysis
As of 2026, most of the City’s pressure reducing stations are between 15 and 27 years old. Typical service life on pressure reducing stations is approximately 35 years.
Age. Figure 2.39 shows the age of the City’s PRS’s in 2026. One (1) PRS has an unknown installation date, and a conditions assessment is recommended to gather information about Main & Olive. As of 2026, one (1) has reached its service life.
57 52
41 40 39 38
36 35 35 35
29 27 27 27
25 23 22
20 20
10 6 6
0 10
20 30
40 50
60 Age (Years)
Equipment Useful Life
Structure Useful Life
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Figure 2.39 – Age of Pressure Reducing Stations in 2026
2.7.7. Pipeline Analysis
Asbestos Cement Pipe. Approximately one third of the City’s pipelines are constructed from asbestos cement pipe material. Asbestos cement pipe was widely utilized in the mid-20th century and is no longer favored due to health effects caused by asbestos fibers. Generally, asbestos cement pipes do not pose a significant health risk from asbestos fibers if they are not damaged. However, there are risks associated with cutting, repair, and removal of the material. Therefore, the City would benefit if the asbestos cement pipelines are replaced at the end of the service life or if the pipeline incurs structural damage. These pipelines have been identified in Section 9.
Hydraulic Capacity. Hydraulic capacity of pipelines is discussed along with hydraulic model results in Sections 6 and 7.
Pipe Service Life. For pipelines, the remaining service life analysis considers the age and material of the pipeline to estimate the typical service life for specific pipe material. For pipelines, the end of the service life is the age when pipe material could be expected to weaken, crack, or rupture. The typical service life for pipelines can vary from 40 to 100 years, but pipes can be utilized beyond their expected service life. It is recommended that once a pipeline reaches the end of its service life, a CCTV inspection be conducted to ascertain the pipeline's condition. If significant damage or degradation is found, pipeline replacement is recommended to maintain the integrity of the distribution system.
The expected service life for each pipeline material within the City’s distribution system is shown in Table
2.22. 0
5 10
15 20
25 30
35 40
45 Age (Years)
PRS Service Life
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Table 2.22 – Pipeline Service Life
Abv. Material Service Life Length
(miles)
AC Asbestos Cement Pipe 70 219.94
CAS Cast Iron Pipe 50 0.01
CEM Cement Pipe 75 1.60
CIPP Cast Iron Pipe 50 10.43
CMLC Cement Mortar Lined and Coated Steel Pipe 100 56.82 CML-TW Cement Mortar Lined and Tape Wrapped Steel Pipe 75 0.73 COP Copper Pipe 50 0.13
DIP Ductile Iron Pipe 100 57.75
GP Galvanized Pipe 50 0.03
PEP Polyethylene Pipe 75 0.17
PVC Polyvinyl Chloride Pipe 70 279.16
RCP Reinforced Concrete Pipe 100 0.00
SP Steel Pipe 50 40.98
Total 667.75
Figure 2.40 shows the quantity of pipeline in miles of pipeline and the remaining service life in 5-year increments. The figure also indicates the type of pipe material. As of 2026, approximately 16 miles of water pipelines have exceeded their service life, and approximately 118 miles are projected to reach the end of their service life within the next 20 years.
Figure 2.40 – Remaining Pipe Service Life as of 2026
0 10
20 30
40 50
60 70
80 90
100
Length (miles)
AC PVC CMLC DIP SP Other
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2.7.7.1. Coronita (Unincorporated) Pipeline Analysis
Coronita is an unincorporated area within the City of Corona’s boundaries. Coronita is a census-designated area in Riverside County. It is located in the western portion of the City.
Pipeline Diameters. The pipeline diameters vary from 4 inches up to 18 inches. Pipelines with diameters lessthan 8-inches are not up to City standards and should be replaced and upsized to a minimum diameter of 8-inches. Figure 2.41 shows the pipelines with diameter sizes within Coronita. Table 1 in Appendix H contains a list of deficient pipelines due to diameter size within Coronita.
Pipeline Materials. The pipeline materials in the Coronita area include asbestos cement (AC), cement mortar lined and coated (CMLC), ductile iron pipe (DIP), polyvinyl chloride (PVC), and steel (SP). As discussed in Section 2.7.7. asbestos cement and uncoated steel pipe should be replaced at the end of their service life. Figure 2.42 shows the pipeline material types within Coronita. Please refer to Table 2 in Appendix H, which contains a list of pipelines within Coronita.
Pipeline Age. Pipelines in the Coronita area were installed between 1946 and 2017. As shown on Figure
2.43. Table 3 in Appendix H depicts the pipelines from the earliest year installed to the latest.
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Figure 2.41 – Coronita Pipeline Diameters
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Figure 2.42 – Coronita Pipeline Materials
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Figure 2.43 – Coronita Pipeline Age
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2.7.7.2. Temescal Valley Pipeline Analysis
Temescal Valley is an area within the City of Corona’s boundaries. It is a census-designated area in Riverside County in the southern portion of the City of Corona. Temescal Valley is roughly 19.3 square miles and hosts the Temescal Basin and Temescal Valley Water District (TVWD).
Pipeline Diameters. The pipeline diameters vary from 2 inches up to 18 inches. Pipelines with diameters less than 8 inches are not up to City standards and should be replaced and upsized to a minimum diameter of 8 inches. Figure 2.44 shows the pipelines with diameter sizes within Temescal Valley. Table 4 in Appendix H contains a list of deficient pipelines due to diameter size within Temescal Valley.
Pipeline Materials. The pipeline materials in the Temescal Valley area include asbestos cement (AC), cement mortar lined and coated (CMLC), ductile iron pipe (DIP), polyvinyl chloride (PVC), and steel (SP).
As discussed in Section 2.7.7. asbestos cement and uncoated steel pipe should be replaced at the end of their service life. Figure 2.45 shows the pipeline material types within Temescal Valley. Table 5 in Appendix H contains a list of Asbestos Cement and Steel pipelines.
Pipeline Age. Pipelines in the Temescal Valley area were installed between 1963 and 2007 as shown on Figure 2.46. Table 6 in Appendix H contains a list of pipelines within Temescal Valley with pipeline installation years.
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Figure 2.44 – Temescal Valley Pipeline Diameters
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Figure 2.45 – Temescal Valley Pipeline Materials
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Figure 2.46 – Temescal Valley Pipeline Age
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2.7.7.3. El Cerrito (Unincorporated) Pipeline Analysis
El Cerrito is an unincorporated area (roughly 2.8 square miles) mostly surrounded by the City of Corona.
It is a census-designated area in Riverside County and is located in the southeastern portion of the City.
Pipeline Diameters. The pipeline diameters vary from 1 inch up to 30 inches. Pipelines with diameters less than 8 inches are not up to City standards and should be replaced and upsized to a minimum diameter of 8 inches. Figure 2.47 shows the pipelines with diameter sizes within El Cerrito. Table 7 in Appendix H contains a list of deficient pipelines due to diameter size within El Cerrito.
Pipeline Materials. The pipeline materials in the Temescal Valley area include asbestos cement (AC), cement mortar lined and coated (CMLC), ductile iron pipe (DIP), polyvinyl chloride (PVC), steel (SP), and cast-in-place pipe (CIPP).
As discussed in Section 2.7.7. asbestos cement and uncoated steel pipe should be replaced at the end of their service life. Figure 2.48 shows the pipeline material types within El Cerrito. Table 8 in Appendix H contains a list of pipelines based on material and life expectancy.
Pipeline Age. Pipelines in the El Cerrito area were installed between 1943 and 2020. as shown on Figure
2.49. Table 9 in Appendix H contains a list of pipelines within El Cerrito based on installation year.
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Figure 2.47 – El Cerrito Pipeline Diameters
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Figure 2.48 – El Cerrito Pipeline Materials
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Figure 2.49 – El Cerrito Pipeline Age
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2.7.7.4. Downtown Pipeline Analysis
The area identified as “Downtown” is referring to the area enclosed by the circular roadway known as Grand Boulevard. This area is within the City’s boundaries and is under the City’s jurisdiction and is roughly
0.6 square miles. It has been deemed an area of concern due to the materials, age, and diameters of the pipelines currently in use.
Pipeline Diameters. The pipeline diameters in the Downtown area vary from 2 inch up to 30 inches.
Pipelines with diameters less than 8 inches are not up to City standards and should be replaced and upsized to a minimum diameter of 8 inches. Figure 2.50 shows the pipelines with diameter sizes within Downtown. Table 10 in Appendix H contains a list of deficient pipelines due to diameter size within Downtown.
Pipeline Materials. The pipeline materials in the Downtown area include asbestos cement (AC), cement mortar lined and coated (CMLC), ductile iron pipe (DIP), polyvinyl chloride (PVC), steel (SP), and cast-inplace pipe (CIPP), copper pipe (COP), and Polyethylene Pipe (PEP).
As discussed in Section 2.7.7. asbestos cement and uncoated steel pipe should be replaced at the end of their service life. Figure 2.51 shows the pipeline material types within Downtown. Table 11 in Appendix H contains a list of deficient pipelines due to pipe material.
Pipeline Age. Pipelines in the Downtown area were installed between 1924 and 2020 as shown in Figure
2.52. Table 10 in Appendix H contains a list of pipelines within Downtown with pipeline installation years. 2-99
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Figure 2.50 – Downtown Pipeline Diameter
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Figure 2.51 – Downtown Pipeline Materials
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Figure 2.52 – Downtown Pipeline Age
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SECTION 3 - WATER SUPPLY
3.1. GENERAL DESCRIPTION
The City’s water supply is composed of groundwater (local supply) and imported water (treated and untreated). This section incorporates relevant information from existing City planning documents that guide the strategy for managing water supply from different sources, including the following plans listed by date of publication.
• City of Corona 2018 Reclaimed Water Master Plan. (2018 Reclaimed Water Master Plan) • City of Corona Water Operations Blending Program Technical Report/Operations Plan, February 2020. (2020 Blending Program Technical Report)
• City of Corona 2020 Urban Water Master Plan, June 2021, Michael Baker International. (2020 UWMP)
• Groundwater Sustainability Plan Bedford-Coldwater Basin, November 2021, TODD Groundwater, Stantec, and H&H Water Resources. (2021 GWSP: Bedford-Coldwater Basin) • Groundwater Sustainability Plan Temescal Basin, January 2022, TODD Groundwater and Carollo Engineers. (2022 GWSP: Temescal Basin)
Table 3.1 and Table 3.2 summarize the historic water supply sources by groundwater and imported water for years 2016–2019 and 2020–2024, respectively, expressed in million gallons per day (MGD). These tables do not denote inactive and standby wells, but this information is included in Section 2.3.1. The groundwater is supplied from two (2) basins: the Temescal Basin and the Bedford-Coldwater Basin. The imported water is provided by the Metropolitan Water District (MWD) through the Colorado River and State Water Project. Imported water is delivered to the City by MWD’s agency member the Western Municipal Water District (WMWD) through the Mills Pipeline (treated) and Lower Feeder Pipeline (untreated). Additional imported water from WMWD is treated at the Arlington Desalter and supplied through an interconnection. The City also maintains one interconnection to supply Home Gardens (Riverside County), and two interconnections with the City of Norco. During an emergency, the City can obtain water from the City of Riverside and Temescal Valley Water District (TVWD) through emergency interconnections. Figure 3.1 provides a hydraulic schematic of the City’s supply sources, and Section 2.3 provides a detailed description of the water supply facilities.
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Table 3.1 – Sources of Supply (MGD), 2016 - 2019
Water Source 2016 2017 2018 2019 Avg
Groundwater
Bedford-Coldwater
Basin
Well No. 3 0.411 0.003 0 0 0.103
Well No. 20 0 0 0 0 0
Well No. 21 1.346 0.682 0.159 0 0.547
Subtotal 1.757 0.685 0.159 0.000 0.650
Temescal Basin
Well No. 7A 0.963 0.509 1.176 1.058 0.927
Well No. 8A 1.557 1.864 1.610 1.332 1.591
Well No. 9A 1.120 1.179 1.247 1.165 1.178
Well No. 11A 0.471 0.356 0.717 0.503 0.512
Well No. 12A 0.444 0.610 0.713 0.737 0.626
Well No. 13 0.025 0 0 0 0.006
Well No. 14 0.769 0.889 0.846 0.825 0.832
Well No.15 0.981 1.129 0.788 1.187 1.021
Well No. 17A 1.074 0.917 0.907 0.557 0.864
Well No. 19 0 0 0.659 1.139 0.450
Well No. 22 1.961 1.848 2.002 1.847 1.914
Well No. 25 1.451 1.587 1.235 0.715 1.247
Well No. 26 0.155 0 0 0 0.039
Well No. 27 0.369 0.235 0.385 0.285 0.319
Well No. 28 0.608 0.638 0.964 0.828 0.759
Well No. 29 0.006 0 0 0 0.002
Well No. 31 0 0 0.554 0.876 0.357
Well No. 33 N/A N/A N/A 1.137 1.137
Subtotal 11.955 11.760 13.803 14.191 12.927
Imported Water
MWD Colorado River
WR – 19 7.464 10.279 9.541 8.590 8.968
WR – 33 4.420 4.075 3.949 4.057 4.125
Subtotal 11.884 14.354 13.490 12.647 13.093
MWD State Water
Project
WR - 24 1.772 1.742 1.979 0.963 1.614
WMWD Arlington Desalter 0.270 0.587 0.446 0.000 0.326
Other[1] Riverside Connection 0 0 0 0 0
TVWD Connection 0 0 0 0 0
Total 27.638 29.128 29.875 27.800 28.610
Note: Data source from City of Corona Water Production information [1] Supply to Corona only during an emergency.
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Table 3.2 – Sources of Supply (MGD), 2020 - 2024
Water Source 2020 2021 2022 2023 2024 Avg
Groundwater
Bedford-Coldwater
Basin
Well No. 3 0 0 0 0 0 0
Well No. 20 0 0 0 0 0 0
Well No. 21 0 0 0 0 0 0
Subtotal 0 0 0 0 0 0
Temescal Basin
Well No. 7A 0.860 0.810 1.120 0.780 0.490 0.812
Well No. 8A 1.200 0.960 0.100 1.060 0.910 0.846
Well No. 9A 1.150 1.150 0.970 0.820 1.000 1.018
Well No. 11A 0.960 1.090 0.810 0.740 0.710 0.862
Well No. 12A 0.610 0.710 0.650 0.690 0.780 0.688
Well No. 13 0 0 0 0 0 0
Well No. 14 0.900 0.220 0 0 0 0.224
Well No.15 1.110 1.120 0.910 0.690 0.640 0.894
Well No. 17A 0.740 0.860 0.950 0.440 0.150 0.628
Well No. 19 1.140 1.140 0.770 0.840 0.960 0.970
Well No. 22 1.710 1.670 1.740 1.890 1.800 1.762
Well No. 25 0.670 0.620 0.490 1.520 1.370 0.934
Well No. 26 0.010 0.440 0.400 0.160 0.180 0.238
Well No. 27 0.650 0.570 0.010 0 0 0.246
Well No. 28 0.720 0.690 0.580 0.640 0.730 0.672
Well No. 29 0 0.260 0.860 0.740 0.820 0.536
Well No. 31 0.740 0.630 1.360 1.270 1.150 1.030
Well No. 33 1.280 1.740 1.190 0.650 0.990 1.170
Subtotal 14.450 14.680 12.910 12.930 12.680 13.530
Imported
Water
MWD Colorado
River
WR – 19 9.480 9.980 12.020 7.470 9.880 9.766
WR – 33 5.420 4.750 4.160 4.880 4.850 4.812
Subtotal 14.900 14.730 16.180 12.350 14.730 14.578
MWD State Water
Project
WR - 24 1.090 0.770 0.380 1.110 0.500 0.770
WMWD Arlington Desalter 0.030 0.090 0 0 0 0.024
Other [1] Riverside Connection N/A N/A N/A N/A N/A N/A
TVWD Connection N/A N/A N/A N/A N/A N/A
Total 30.470 30.270 29.470 26.390 27.910 28.902
Note: Data source from City of Corona Water Production information. Data was provided with precision to the hundredths decimal place and a trailing zero was added for consistency. [1] Supply to Corona only during an emergency.
2.5 MG 1640' HWL 2.0 MG 1380' HWL 4.6 MG 1380' HWL PAYETTE (4) EAGLE GLEN ZONE 6 (3+FIRE)2.5 MG 1220' HWL 1.6 MG 1220' HWL EAGLE GLEN ZONE 5 (2) 4.0 MG 1220' HWL WELL 21 WELL 20 WELL 3 H AQUINO (2) 6.0 MG 1020' HWL ORANGE HEIGHTS 4.0 MG 905' HWL H MORITA (2 + FIRE) ARCADIA WELL 7A WELL 13 DROP VALVE 2.0 MG 1060' HWL 2.0 MG 1060' HWL LESTER ZONE 4 (4) LESTER ZONE 5 (5) CHASE (4) MWD WR-19 2.5 MG 905' HWL CRESTA VERDE (4) LESTER RAW (2) GARRETSON ZONE 3 (6) WELL 28 WELL 29 WELL 26 TEMESCAL DESALTER WELLS WELL 9A WELL 25 WELL 31 WELL 22 TEMESCAL DESALTER SAMPSON FCS WELL 14 WELL 15 WELL 27 WELL 12A WELL 11A WEST WELLS 2.0 MG 905' HWL 3.0 MG 1020' HWL HARLAN HILLS (2+FIRE) MABEY CANYON (2+FIRE) TO ZONE 1310 1.6 MG 1220' HWL BORDER (3) AVENIDA DEL VISTA 4.0 MG 1060' HWL MONTANA RANCH (2) MWD WR-33 SDO RAW (3) 9.1 MGD KRAFT RANCH (2+FIRE) TO ZONE 1315 SERFAS CLUB (2) 1.5 MG 725' HWL B 30.0 MGD Figure 2.1 Existing Water System Hydraulic Schematic SONRISA MOUNTAIN GATE CAJALCO ARLINGTON DESALTER 905 TO NORCO 1
RIVER & KALUS
HARRINGTON
ALCOA
NORTH SMITH
SOUTH SMITH
YORBA
AUTO CENTER DR
RIDGELINE
GREEN RIVER DOMINGUEZ RANCH ZONE 725 ZONE 820 ZONE 780 WELL 8A WELL 17A WELL 32 WELL 33 GACWTP 15.0 MGD *MILLS CONNECTION BEDFORD CANYON TO ZONE 1480 SIERRA BELLA EAST SIERRA BELLA WEST TO ZONE 1250 SIERRA BELLA (2) FREEDOM CW19 MANGULAR ZONE 4 (3) MANGULAR ZONE 3 (2) TO ZONE 1235 TO ZONE 1130 TO ZONE 1220 TO NORCO 2 TEMESCAL WEST TO/FROM CITY OF RIVERSIDE ZONE 925 B GARRETSON ZONE 4 (3) TEMESCAL EAST TVWD TVWD 2 (1) TVWD 1
YUMA VILLAGE LOOP TO ZONE 1045MAGNOLIAZONE 920 TO HOME GARDENS ZONE 920 & TANK M M AD TO ZONE 1060 GREEN RIVER *MILLS CONNECTION LESTER 2.0 MG 905' HWL TO HOME GARDENS YUMA RELIEF VALVE ARLINGTON DESALTER 1060 H CW22 WELL 19 EAST WELLS HUMMING BIRD TO ZONE 960
SAN PONTE
MT SERENATA NICHOLAS FC H H H *MILLS CONNECTION TOM BARNES 1 MG MWD WR-29 1000 1100 900 800 700 600 1200 1300 1400 1500 1600 1700 500 400 300 1000 1100 900 800 700 600 1200 1300 1400 1500 1600 1700 500 400 300 B R-3 Figure 2.1 Existing Water System Hydraulic Schematic RIVERSIDE EMERGENCY INTERTIE PRV
FCV MWD WR-24 *MILLS CONNECTION BEDFORD CANYON MWD WR-24 *MILLS CONNECTION LESTER *MILLS CONNECTION TOM BARNES TO ZONE 1380 TO ZONE 1380 TO ZONE 1220 TO ZONE 1060 TO ZONE 1220 *MWD WR-24 CONNECTION Source Pipe X.X MG XXXX HWL Potable Water Tank Pump Station Water Treatment Plant X.X MGD B Blending Facility Distribution to customers Groundwater Well Connection to MWD MWD WR-X H Hydropneumatic tank MILLS CONN Mills Connection GACWTP Common Well Valves CWXX Zone Valve (normally closed) Inactive Pump Station Inactive Groundwater Well Sustaining Station Flow Meter TVWD Temescal Valley Water District MAD Arlington Desalter Relief Valve Check Valve X.X MGD Inactive Water Treatment Plant Inactive Connection to MWD MWD WR-X Granular Activated Carbon Water Treatment Plant Pressure Reducing Station or Flow Control Station (as noted) Distribution Pipe Groundwater Supply Treated Imported Water Supply Untreated Imported Water Supply Interconnection Emergency Interconnection City of Corona
Figure 3.1 City of Corona's Sources of Water Supply
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3.2. MONTHLY PRODUCTION
The City’s production of groundwater and the volume of imported water (purchased from and delivered by WMWD) varies throughout the year. For this section, imported water is included in the production totals. Figure 3.2 shows the City’s monthly production data from 2016 through 2019, and Figure 3.3 shows the monthly production data for the subsequent period, 2020 through 2024. It should be noted that the majority of the groundwater goes through the Temescal Desalter Facility ,and Figure 3.2 and Figure 3.3 do not account for any losses from treatment at the Temescal Desalter.
It is expected that the production rate will be slightly higher than the demand rate; however, too much variation between the two would indicate the distribution system has deficiencies that need to be addressed, including but not limited to system leakage.
Summer water production is approximately twice the winter production, which is expected due to higher demand during hotter, drier months. The average production in 2016 through 2019 was 32,048 Acre-ft (28.61 MGD), and the average production in 2020 through 2024 was 32,419 AF (28.9 MGD).
Figure 3.2 – City of Corona's Monthly Production from 2016 - 2019 Note: Data source taken from Corona’s Annual Production Recapitulation Data -
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
AF
Month
2016 2017 2018 2019
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Figure 3.3 – City of Corona's Monthly Production from 2020 - 2024 Note: Data source taken from Corona’s Annual Production Recapitulation Data
3.3. GROUNDWATER
3.3.1. Basins
Groundwater wells extract groundwater from the Temescal and Bedford-Coldwater Basins. Each basin is managed by a Groundwater Sustainability Agency (GSA) and has a Groundwater Sustainability Plan (GSP) as mandated by the Sustainable Groundwater Management Act.
3.3.1.1. Temescal Basin
Description of Basin
The Temescal Basin, shown in Figure 2.24, is in the southwesterly region of the Santa Ana Valley Groundwater Basin. The Temescal Basin is bounded by the Santa Ana River to the North, the RiversideArlington Basin to the east, the Bedford-Coldwater Basin to the south, and the Santa Ana Mountains to the west.
The Temescal Basin Groundwater Sustainability Agency (Temescal GSA) is comprised of three water agencies: the City of Corona, the City of Norco, and Home Gardens County Water District (HGCWD).
Currently, the City of Corona is the leading water purveyor within the Temescal Basin, and currently the only water agency that pumps groundwater from the Temescal Basin. The City of Corona supplies a -
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
AF
Month
2020 2021 2022 2023 2024
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portion of the City of Norco’s imported water, and 100 percent of HGCWD’s imported water (see Section
2.3.2 for details on interconnections). The City of Corona’s water production totals include the water delivered to the City of Norco and HGCWD. If the City of Norco or HGCWD were to begin pumping groundwater directly from the Temescal Basin in the future, the groundwater would likely require treatment.
Sustainability
The Temescal GSA’s most recent Groundwater Sustainability Plan is the 2022 GWSP: Temescal Basin, and the information in this section is largely reported from the 2022 GWSP: Temescal Basin. The Temescal Basin can be recharged both naturally and through artificial recharge. Natural recharge includes subsurface inflow, return flow, dispersed recharge, and inflow from adjoining groundwater basins.
According to the 2022 GWSP: Temescal Basin, percolation from the City’s reclaimed water, a form of artificial recharge, accounts for an estimated 25 percent of 2019 through 2068 baseline basin inflow. The City’s Water Reclamation Facility (WRF) 1 and WRF 2 are used for Temescal Basin groundwater recharge through percolation ponds as explained in the City’s 2020 UWMP and in Section 0 Baseline basin inflow is expected to remain relatively constant over time, but it can vary from year to year based on rainfall.
Outflows from the Temescal Basin include natural outflows and water extracted from wells for potable and non-potable uses. Natural discharges include groundwater discharges to streams, riparian evapotranspiration, and outflow to adjoining basins. Table 3.3 shows the comparison of inflows and outflows for the Temescal Basin as presented in the 2022 GWSP: Temescal Basin.
Table 3.3 – Temescal Basin Sustainability
AFY MGD [1]
Water Balance Items Baseline
2019-2068
Growth Plus
Climate Change
2019-2068
Baseline
2019-2068
Growth Plus
Climate Change
2019-2068
Groundwater Inflow
Percolation from Streams 7,918 8,817 7.07 7.87
Bedrock Inflow 1,084 1,314 0.97 1.17
Dispersed Recharge: Non-Irrigated Land 2,742 2,668 2.45 2.38 Dispersed Recharge: Irrigated Land 3,172 3,253 2.83 2.90 Pipe Leaks 2,151 2,174 1.92 1.94
Reclaimed Water Percolation 6,122 6,122 5.47 5.47
Inflow from Adjoining Basins 1,026 126 0.92 0.11
Inflow Total 24,213 24,473 21.62 21.85
Groundwater Outflow
Wells: Municipal, Industrial, and Domestic 15,615 15,615 13.94 13.94 Wells: Agricultural 22 23 0.02 0.02
Groundwater Discharge to Streams 1,739 1,504 1.55 1.34
Riparian Evapotranspiration 4,538 4,997 4.05 4.46
Outflow to Adjoining Basins 2,364 2,301 2.11 2.05
Outflow Total 24,278 24,439 21.67 21.82
Note: Data from 2022 Groundwater Sustainability Plan: Temescal Basin [1] Flows presented as MGD are for conceptual purposes only, the actual rate of flow may not be constant during the year.
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Since the Glen Ivy Wells are no longer active due to water quality issues, the City has extracted more water from the Temescal Basin wells. Based on the pumping rates in Table 3.3, Temescal Basin has a slight overdraft in the baseline 2019 through 2068, and no further increases in well production are manageable without putting the basin in overdraft unless additional water recharge to the Temescal Basin occurs including increased reclaimed water recharge.
Groundwater Quality
Groundwater quality in the Temescal Basin is characterized by elevated levels of nitrate, total dissolved solids, perchlorate, and emerging contaminants such as PFOS and PFOA in several wells. Detailed water quality data, monitoring results, treatment descriptions, and state and federal standards are provided in Section 8 of this report.
3.3.1.2. Bedford-Coldwater Basin
Description of Basin
Previously, the Bedford-Coldwater Basin was represented as two distinct basins, Bedford Basin and Coldwater Basin, but it has been combined into one basin. The Bedford-Coldwater Basin, shown in Figure
2.25, is a part of the Elsinore Valley Groundwater Basin and covers approximately 6,300 acres. The Bedford-Coldwater Basin is bounded by the Temescal Basin to the northwest, Estelle Mountain to the east, the Lake Elsinore Basin to the southeast, and Santa Ana Mountain to the west.
The Bedford-Coldwater Groundwater Sustainability Agency (Bedford-Coldwater GSA) is comprised of three water agencies: the City of Corona, Elsinore Valley Municipal Water District, and the Temescal Valley Water District. All three water agencies pump groundwater from the Bedford-Coldwater Basin. Only the City of Corona’s wells are shown in Figure 2.25. During routine operations, these agencies do not exchange water; however, Temescal Valley Water District maintains an emergency connection that can supply the City of Corona.
Sustainability
The Bedford-Coldwater GSA’s most recent Groundwater Sustainability Plan is the 2021 GWSP: BedfordColdwater Basin, which divides the Bedford-Coldwater Basin into the Bedford Management Area and the Coldwater Management Area. Both management areas have an inflow from subsurface inflows, percolation from streams, bedrock inflow, dispersed recharge, and leaks. The Bedford Management Area also has recharge from a quarry and the Temescal Valley Water District’s WRF, and the Coldwater Management Area has no artificial recharge. Natural outflows from the Bedford and Coldwater Management Areas include subsurface outflow, groundwater discharge to streams, riparian evapotranspiration, and quarry operation losses. Table 3.4 shows the comparison of inflows and outflows for the Temescal Basin as presented in the 2021 GWSP: Bedford-Coldwater Basin.
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Table 3.4 – Bedford-Coldwater Basin Sustainability
Water Balance Items
Bedford Management Area Coldwater Management Area
AFY MGD [1] AFY MGD [1]
Baseline
2019-
2068
Growth
Plus
Climate
Change
2019-2068
Baseline
2019-
2068
Growth
Plus
Climate
Change
2019-2068
Baseline
2019-
2068
Growth
Plus
Climate
Change
2019-2068
Baseline
2019-
2068
Growth
Plus
Climate
Change
2019-2068
Groundwater Inflow
Subsurface Inflow 102 93 0.09 0.08 34 48 0.03 0.04
Percolation from Streams 1,661 1,714 1.48 1.53 2,780 2,779 2.48 2.48 Bedrock Inflow 776 828 0.69 0.74 467 435 0.42 0.39
Dispersed Recharge: Non-Irrigated Land 929 1,031 0.83 0.92 1,164 1,575 1.04 1.41 Dispersed Recharge: Irrigated Land 559 940 0.50 0.84 289 396 0.26 0.35 Pipe Leaks 33 92 0.03 0.08 17 32 0.02 0.03
Reclaimed Water Percolation 1,868 2,161 1.67 1.93 0 0 0.00 0.00 Inflow from Adjoining Basins 162 471 0.14 0.42 0 0 0.00 0.00 Inflow Total 6,090 7,330 5.44 6.54 4,751 5,265 4.24 4.70 Groundwater Outflow
Subsurface Outflow 498 423 0.44 0.38 15 7 0.01 0.01
Wells: Municipal, Industrial, and
Domestic 1,315 1,895 1.17 1.69 3,002 3,072 2.68 2.74
Wells: Agricultural 0 0 0.00 0.00 40 88 0.04 0.08
Groundwater Discharge to Streams 990 1380 0.88 1.23 2 1 0.00 0.00 Riparian Evapotranspiration 760 1015 0.68 0.91 154 168 0.14 0.15 Outflow to Adjoining Basins 2,422 2,466 2.16 2.20 0 0 0.00 0.00 Outflow Total 5,985 7,179 5.34 6.41 3,213 3,336 2.87 2.98 Note: Data from 2021 Groundwater Sustainability Plan: Bedford-Coldwater Basin [1] Flows presented as MGD are for conceptual purposes only, the actual rate of flow may not be constant during the year.
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There are no potable wells within the Bedford Management Area, however there are non-potable wells used for irrigation. The City extracts non-potable water from the Bedford management area using two non-potable wells, extracting approximately 336 AFY for non-potable use. Based on the 2021 GWSP:
Bedford-Coldwater Basin, the Bedford management area could have a sustainable yield of 2,047 AFY. In comparison, the Coldwater management area can have a sustainable yield of 5,088 AFY.
Groundwater Quality
Groundwater quality in the Bedford-Coldwater Basin is characterized by historic elevated levels of nitrate and some exceedances of total dissolved solids. Detailed water quality data, monitoring results, treatment descriptions, and state and federal standards are provided in Section 8 of this report.
3.3.2. Wells
Section 2.3.1 summarizes specific well information including well locations, capacities, pumping facilities, and operational characteristics.
3.3.2.1. Drinking Water Source Assessment and Protection (DWSAP) Program The City has completed a Drinking Water Source Assessment and Protection (DWSAP) Program for each well in the potable water system as required by the State Board’s Division of Drinking Water (DDW). The DWSAP includes general information on each well including identification number, location, sanitary conditions, enclosure/housing, construction features, and production.
3.3.2.2. Temescal Basin Wells
Eighteen (18) of the City’s potable wells are located in the Temescal Basin. The water from these wells is treated at the Granular Activated Carbon (GAC) WTP and the Temescal Desalter. Based on the January 2018 flows presented in the City’s 2020 Blending Program Technical Report (Appendix A), the average flow of the Temescal Desalter is approximately 10.2 MGD. This accounts for about 80% of the City’s groundwater supply from the Temescal Basin. Section 2.3.1 includes a well inventory and specifications.
3.3.2.3. Bedford-Coldwater Basin Wells
Three (3) of the City’s potable wells and two (2) non-potable wells are located in the Bedford-Coldwater Basin. Potable Well 3, 20, and 21 are currently inactive, but historically supplied the 1136 Glen Ivy Zone.
Section 2.3.1 includes a well inventory and specifications.
3.3.2.4. Well Production Analysis
A well production analysis assesses the amount of water a well can produce over time. Table 3.5 shows the production capacity of each of the City’s wells based on their design capacity and the most current SCE efficiency test reports (included in Appendix C). The efficiency of each pump deteriorates over time, reducing its pumping capacity. The total design capacity for all wells is 32,082 GPM (46.20 MGD). The total design capacity for active wells is 25,272 GPM (36.39 MGD). The total most current capacity (SCE Efficiency Tests) for active wells is 12,347 GPM (17.78 MGD).
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Table 3.5 – Well Production Capacity (GPM)
Wells Efficiency Test Date
Most Current
Capacity (SCE
Capacity
Tests) (gpm)
Normal
Operation
(Hz)
Design
Capacity
(gpm)
Well #3 [2] January 20, 2015 564 [3] Varies 1,060
Well #7A April 9, 2024 741 50 1,000
Well #8A April 9, 2024 656 43.5 1,650
Well #9A April 23, 2024 706 49.4 1,500
Well #11A April 17, 2024 524 50.7 700
Well #12A April 17, 2024 517 [3] Varies 1,100
Well #13 [1] March 15, 2015 365 [3] Varies 1,000
Well #14 August 28, 2017 726 Not Noted 1,000
Well #15 April 17, 2024 524 [3] Varies 1,100
Well #17A May 8, 2024 1,127 [3] Varies 1,400
Well #19 May 8, 2024 477 50.4 2,100
Well #20 [1] February 17, 2015 311 [3] Varies 2,500
Well #21 [2] January 20, 2015 1,138 [3] Varies 2,250
Well #22 May 2, 2024 1,421 [4][3] Varies 3,500
Well #25 April 23, 2024 1,210 57.1 3,500
Well #26 December 1, 2022 273 51.9 1,000
Well #27 October 30, 2019 563 [3] Varies 500
Well #28 May 2, 2024 670 [3] Varies 2,000
Well #29 May 2, 2024 640 [3] Varies 750
Well #31 April 23, 2024 907 [3] Varies 1,000
Well #32 [1] No pumping equipment installed
Well #33 April 9, 2024 665 47 1,472
Total Capacity (Active Only) 12,347 25,272
Total Capacity 14,724 32,082
[1] Inactive Wells
[2] Standby Wells
[3] Well Pump Efficiency Test did not include a normal operating hertz, so the average capacity of the well tests was used as the Most Current Capacity.
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3.4. IMPORTED WATER
The City’s untreated imported water and treated imported water are described below. Figure 3.4 shows the locations of the untreated water turnouts and associated City WTPs, the treated water turnout from the Henry J. Mills WTP (WR-24), and the treated water interconnection from the Arlington Desalter.
Section 2 provides detailed information on imported water supply locations, pressures zones, and water treatment plant (WTP) capacities.
3.4.1. Untreated Imported Water
The Lower Feeder Pipeline supplies most of the City’s untreated imported water, accounting for approximately 91% of the City’s total imported water supply. Section 2.3.2.1 details three turnouts that connect the City to the Lower Feeder Pipeline and subsequent treatment provided by the City’s system. • WR-19 gravity feeds to the Lester WTP
• WR-29 can be pumped through the Green River Raw Booster Pump Station to the Green River WTP, but WR-29, the Green River Raw Booster Pump Station, and the Green River WTP are currently inactive.
• WR-33 can be pumped through the Sierra Del Oro Raw Water Booster Pump Station to the Sierra Del Oro (SDO) WTP.
3.4.2. Treated Imported Water
The City receives treated imported water from WMWD through both the Arlington Desalter Interconnection and from the Mills Pipeline turnout (WR-24). • WMWD treats water from the State Water Project at the Henry J. Mills WTP and supplies it to the City through Mills Pipeline turnout (WR-24).
• WMWD treats groundwater at the Arlington Desalter and supplies it to the City through the Arlington Desalter interconnection. Typically, the Arlington Desalter is not used year-round and is primarily utilized to supplement supply in the summer months.
Table 3.6 and Table 3.7 show the treated and untreated imported water supplied for years 2016–2019 and 2020–2024, respectively. Figure 3.5 and Figure 3.6 shows the distribution of imported water supplied by each imported water source.
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Figure 3.4 – Map of Imported Water Supply Locations
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Table 3.6 – Imported Water Capacity and Historical Use (Acre-ft/Yr.), 2016 - 2019 Source 2016 2017 2018 2019 Average
Untreated Imported
Water
WR - 19 (Lester WTP) 8,362 11,514 10,688 9,622 10,046
WR – 33 (SDO WTP) 4,951 4,565 4,423 4,545 4,621
Treated Imported Water WR – 24 (Henry J Mills WTP) 1,985 1,951 2,217 1,079 1,808 Arlington Desalter 302 658 500 - 365
Total Imported Water Total 15,600 18,688 17,828 15,246 16,840 Total (MGD) 13.89 16.68 15.91 13.61 15.02
Based on City of Corona’s Annual Production Recapitulation Data Table 3.7 – Imported Water Capacity and Historical Use (Acre-ft/Yr.), 2020 - 2024 Source 2020 2021 2022 2023 2024 Average
Untreated Imported
Water
WR - 19 (Lester WTP) 10,619 11,179 13,464 8,367 11,067 10,939 WR – 33 (SDO WTP) 6,071 5,321 4,660 5,466 5,433 5,390
Treated Imported Water WR – 24 (Henry J Mills WTP) 1,221 863 426 1,243 560 863 Arlington Desalter 34 101 - - - 27
Total Imported Water Total 17,945 17,463 18,550 15,077 17,060 17,219 Total (MGD) 15.98 15.55 16.51 13.42 15.19 15.33
Based on City of Corona’s Annual Production Recapitulation Data
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Figure 3.5 – Average Imported Water by Supply Source (2016 - 2019 Average) Figure 3.6– Average Imported Water by Supply Source (2020 - 2024 Average)
3.5. WATER TREATMENT FACILITIES
Section 2.3.3, Figure 2.28, and Appendix G include detailed information on the water treatment facilities and capacities of each facility.
3.6. RECLAIMED WATER
3.6.1. Existing Reclaimed Water System
The City’s reclaimed water goals are documented in the 2018 Reclaimed Water Master Plan, and the information in this section is largely reported from the plan. Per Ordinance 2854 (Recycled Water Rules and Regulations): It is the policy of the City of Corona that recycled water be used for any purposes or WR - 19, 60%
WR - 33, 27%
WR - 24, 11%
Arlington Desalter, 2%
WR – 19, 64%
WR – 33, 31%
WR - 24, 5% Arlington Desalter, 0%
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project approved for recycled water use, when it is economically, financially and technically feasible, as mandated by the Recycled Water Ordinance.
3.6.1.1. Reclaimed Water Supply
As shown in Table 3.8, the City’s reclaimed water sources of supply are three water reclamation facilities (WRF 1, WRF 2, and WRF 3) and two non-potable wells (non-potable wells 1 and 2), and the average annual production from these sources is approximately 11.64 MGD (approximately 13,038 AFY).
According to the 2018 Reclaimed Water Master Plan, WRF 1 and WRF 2 are conventional treatment plants, and WRF 3 is a membrane bioreactor (MBRs). WRF 3 may be decommissioned in the future.
Table 3.8 – Reclaimed Water Supply (from 2018 Reclaimed Water Master Plan) Source
Permitted Capacity
(MGD)
Average Production
(MGD)
WRF 1 11.5 [1] 8.61
WRF 2 3 2.05 [2]
WRF 3 1 0.68
Non-potable Well N/A 0.30
Western Riverside County Regional
Wastewater Authority (WRCRWA) [3]
2.62 N/A
Total 18.12 11.64
[1] Permitted capacity is 11.5 MGD. The design capacity is 11.5 MGD for secondary treatment, and 15.0 MGD for tertiary filtration.
[2] Average production excludes required return flows within WRF 2. [3] Future booster pump station capacity.
The WRCRWA Southerly Pipeline, completed in 2024, extends from the WRCRWA plant and connects to the City's existing recycled water system within River Road in the City of Norco. This pipeline can potentially convey an additional capacity up to 5.46 MGD once the future pump station is commissioned.
3.6.1.2. Reclaimed Water Demand
Reclaimed water demand is the contractually required discharge to the Santa Ana River watershed, the Temescal Basin recharge through percolation ponds, and the City’s reclaimed water distribution system.
Table 3.9 – Reclaimed Water Demand
Demand Reclaimed Water Supply Source Average Demand Volume Santa Ana River Watershed WRF 1 at FCS-Creek 1,625 AFY (1.45 MGD) [1] Temescal Basin Groundwater
Recharge
Treated at WRF 1 and WRF 2 and
discharged through North Cota, South
Cota, and Lincoln percolation ponds
6.5 MGD
City’s Non-potable system
WRF 1, WRF 2, WRF 3, and Non-potable
wells
Varies based on non-potable
production
[1] In accordance with the 1968 Agreement between the City and Western Municipal Water District Discharge from Lincoln/Cota percolation ponds supplied by WRF 1 and 2 must be 1,625 AFY (1.45 MGD) from the Temescal Wash into the Prado Wetlands.
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Santa Ana River Watershed. The City is obligated under a 1968 agreement with the WMWD, known as the Prado Settlement, to discharge an annual average of 1,625 acre-feet per year (AFY) (1.45 MGD) of reclaimed water to the Santa Ana River Watershed. This discharge is a legal requirement to maintain minimum base flows in the Santa Ana River at Prado Dam, ensuring downstream water users receive adequate water quantity and quality. Reclaimed water (WRF 1 effluent) is discharged Flow Control Station (FCS-Creek). According to the 2018 Reclaimed Water Master Plan, this mandated discharge represents approximately 12.8% of the City's reclaimed water production and is not available for other City uses.
Temescal Basin Recharge Through Percolation Ponds. In addition to the mandated Santa Ana River Watershed discharge, the City also discharges reclaimed water for Temescal Basin groundwater recharge.
WRF 1 and WRF 2 discharge to the City’s three (3) percolation ponds(Cota North, Cota South, and Lincoln).
California’s State Water Resources Control Board (SWRCB) requires tertiary effluent quality for discharge to the City’s percolation ponds. Initially, the SWRCB only permitted the City a tertiary effluent capacity of 9 MGD; however, the Water Board has recently increased this capacity to 15.5 MGD based on the treatment capacity of the WRFs.
Reclaimed Water Distribution System. The remaining production enters the reclaimed distribution system to help offset the use of potable water for irrigation. By using reclaimed water for irrigation systems previously supplied with potable water, the City effectively augments its potable water supply.
This strategy conserves potable water by substituting it with reclaimed water for irrigation purposes.
The primary demand of the reclaimed water distribution system is irrigation which occurs at city parks, schools, and other City and private landscaping. A small amount of reclaimed water serves industrial dual plumbing (e.g. toilet flushing), sewer flushing, street sweeping, replenishment of cooling water, replenishment of recreational impoundment, firefighting training, and construction needs (e.g. dust control and soil compaction).
3.7. WATER CONSERVATION
Water conservation is an integral component of long-term water resource planning in California and within the City of Corona. State legislation and local programs require urban water suppliers to improve water use efficiency, reduce per-capita water demand, and promote sustainable water use practices.
These efforts help maintain water supply reliability, reduce strain on imported water sources, and minimize the need for costly infrastructure expansion.
California has adopted several statewide initiatives to improve water use efficiency. A key policy framework is the Water Conservation Act of 2009, which established a statewide goal to reduce urban per-capita water use by 20 percent by 2020. The legislation requires urban retail water suppliers to establish baseline water use, adopt interim targets, and implement conservation programs to achieve long-term efficiency goals.
More recently, California adopted additional efficiency standards through AB 1668 and SB 606, commonly referred to as the “Make Water Conservation a California Way of Life” framework. These regulations establish long-term water use objectives for urban water suppliers, including indoor residential efficiency standards and landscape irrigation efficiency requirements. These state mandates are implemented through local planning efforts such as an Urban Water Management Plan and local water conservation
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programs. Compliance with these requirements ensures eligibility for state funding programs and helps agencies maintain resilient water supply portfolios.
The City of Corona has implemented a variety of conservation measures designed to reduce water demand while maintaining reliable service to residents and businesses. The City’s water conservation program includes both permanent efficiency measures and drought response actions that can be implemented during periods of water shortage. Corona’s municipal code establishes a multi-stage water conservation and drought response framework, consisting of five conservation stages that correspond to varying levels of water supply conditions. Each stage includes progressively stricter conservation requirements intended to reduce demand and protect available water supplies.
Under normal water supply conditions, the City promotes efficient water use through public education, landscape irrigation management, and enforcement of wasteful water use restrictions. Examples of standard conservation requirements include:
• Prohibition of irrigation during or shortly after measurable rainfall • Requirements to repair leaks and malfunctioning irrigation systems • Restrictions on water runoff from irrigation systems
• Limitations on outdoor water uses such as washing hard surfaces or overfilling decorative water features
• Use of shut-off nozzles when washing vehicles
In addition to regulatory measures, the City encourages water efficiency through outreach programs, conservation incentives, and promotion of water-efficient technologies for residential, commercial, and institutional customers.
Water conservation reduces overall system demand and helps defer the need for additional supply development or distribution system expansion. Through implementation of state-mandated efficiency targets and locally administered conservation programs, the City of Corona continues
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SECTION 4 - WATER USE
4.1. GENERAL DESCRIPTION
Section 4 presents the current water-use characteristics within the City’s service area and develops future water-demand projections through buildout, currently anticipated around 2040 per the City’s latest General Plan. This section also evaluates hourly demand variations, diurnal curves, and historical consumption trends.
The analysis relies on City water-meter billing records, production-flow data from the City’s water treatment and groundwater facilities, and GIS-based land-use categories used for demand allocation.
Production data used in this section were obtained from calibrated flow meters at the City’s water-supply facilities. A detailed summary of water-supply production is provided in Section 3.
Historical and projected water use is categorized by land-use type, consistent with the City’s planning datasets. The methodology for each component of the demand analysis is described in the subsections that follow.
Selection of Representative Demand Year
Water-use patterns during 2020 and the subsequent years were influenced by COVID-19 pandemic conditions, including temporary business closures, work-from-home patterns, and behavioral changes that altered typical water-demand profiles.
To avoid COVID-related anomalies, the City’s 2024 metered consumption data were selected as the representative demand year for this Master Plan. The 2024 dataset reflects stabilized community behavior, post-pandemic economic normalization, and typical commercial and residential occupancy patterns. These data were therefore used to determine the City’s average water demand and to calculate historical peaking factors.
Historical Water Use
A review of the City’s historical annual water use shows that system-wide water demand has varied over time in response to population growth, economic cycles, and statewide conservation efforts. Annual water use increased through the 1990s and early 2000s, reaching a peak of approximately 42 MGD in 2007. Water use then declined significantly beginning in 2008, influenced by the economic recession, multiple statewide drought-response measures, and long-term conservation trends. In recent years, average annual water use has stabilized at approximately 28 to 30 MGD despite continued population growth, indicating improved water-use efficiency throughout the community.
Historical water-use records were compiled from multiple sources, including the City of Corona’s 2020 Urban Water Management Plan (UWMP) and annual production records. The 2020 UWMP provided historical records for 1990–2010 and quantified water use for 2016–2020, in accordance with the Water Code requirements to report a five-year range of data. Water use records for 2020 through 2024 were developed using City’s annual production recapitulation datasets.
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For this Master Plan, these datasets were consolidated to develop a continuous historical record and to illustrate long-term water-use trends. A tabulated summary of historical consumption is presented in Table 4.1, and the data are shown graphically in Figure 4.1.
Table 4.1 – Historical Water Demand
Year AFY MGD Year AFY MGD
1990 25,992 23.20 2011 34,918 31.17
1991 22,123 19.75 2012 35,534 31.72
1992 22,861 20.41 2013 36,574 32.65
1993 23,624 21.09 2014 36,087 32.21
1994 25,621 22.87 2015 30,902 27.59
1995 26,402 23.57 2016 30,958 27.64
1996 30,416 27.15 2017 32,626 29.12
1997 32,770 29.25 2018 33,464 29.87
1998 31,022 27.69 2019 31,138 27.80
1999 38,113 34.02 2020 34,241 30.57
2000 39,705 35.44 2021 33,924 30.28
2001 39,012 34.83 2022 33,031 29.49
2002 43,436 38.77 2023 29,555 26.38
2003 43,131 38.50 2024 31,338 27.97
2004 43,228 38.59
2005 42,771 38.18
2006 44,834 40.02
2007 46,788 41.77
2008 45,265 40.41
2009 43,351 38.70
2010 39,185 34.98
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Figure 4.1 – Historical Water Demands (MGD)
4.2. CORRELATION BETWEEN METERS, PARCELS, AND LAND USE
Methodology
To evaluate water use by land use type, historical meter-read data were correlated with associated parcel information and land use designations. Each meter was assigned a land use type using a combination of billing database attributes and geospatial information within the City’s GIS.
The primary source of meter information was the City of Corona’s monthly billing database, which includes account numbers, parcel numbers, designated land use types, meter addresses, meter sizes and types, and other attributes. However, not all meters contained complete or current information regarding parcel identification or land use designation. Missing or inconsistent records were resolved using geospatial analysis.
To ensure each meter was geographically matched to the correct parcel, the parcel number or physical meter address was first used to place the meter in the City’s GIS. Once positioned, the County assessor parcel map was overlaid, allowing each meter to be linked to the parcel on which it is located. Some meters required individual review to confirm or correct their placement. After the meter locations were finalized, the City’s land use layers were overlaid to associate each meter with its appropriate land use category.
This correlation between meter location, parcel number, and land use enabled the assignment of historical water-use records to specific land uses. These data were then used to develop per-land-use demand factors for projecting future water needs, as discussed in Section 4.3. and Section 4.9. The geospatial meter locations also allowed each meter to be incorporated correctly into the hydraulic model, ensuring the model reflects these spatial demand distributions.
0.00 5.00
10.00 15.00
20.00 25.00
30.00 35.00
40.00 45.00
1990 1995 2000 2005 2010 2015 2020 2025
Water Demand (MGD)
Year
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Database Attributes
The City of Corona maintains two related datasets for water meters. The first contains basic meter information for each individual meter and its associated account. The second dataset contains meter-read data, including read dates and consumption values tied to a unique meter identifier. When these two datasets are combined, a complete record can be developed for each meter that includes both account characteristics and historical water use.
These datasets are maintained in the City’s billing database, and key fields are imported into the GIS for planning and modeling purposes. GIS entries for each meter include meter size, installation date, latitude, longitude, land use type, parcel number, and other fields needed for hydraulic modeling and inventory management.
Protocol for Future Meters
It is recommended that the City continue to maintain and update the meter information database for all new meter installations. New meters should be entered with complete account information, parcel number, meter size, land use type, and location coordinates to ensure seamless integration with the GIS and hydraulic model.
When a meter is retired or replaced, the associated database entries should be updated accordingly. The City is developing a standardized protocol for entering or modifying meter data, including a required form that will be completed before any changes are finalized. This protocol will ensure that missing fields are minimized and that data integrity is maintained across all planning and operational systems.
4.3. WATER DEMANDS
For the water demand evaluation, water meter-read data from the year 2024 was selected as the representative historical period. Data from 2020–2023 were excluded because water use during those years was influenced by COVID-19 pandemic conditions, including temporary business closures, shifts to work-from-home practices, and other atypical water-use behaviors. These factors made 2020–2023 unrepresentative of long-term, stable water demand patterns.
Meter-read data includes consumption for each meter based on its individual read cycle. Most meters are read monthly though some reading cycles vary slightly. For each year of analysis, the total read volume and total read-cycle days were summed to determine the average-day demand for each meter. Meter demands were then aggregated by land use category and by pressure zone to support subsequent modeling and planning tasks.
The average annual demands for 2016–2024 are summarized in Table 4.2.
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Table 4.2 – Yearly Meter Demands
Year Average Demand (AFY) [1] Average Demand (MGD)
2016 21,108 18.84
2017 24,719 22.07
2018 27,384 24.45
2019 27,480 24.53
2020 30,318 27.07
2021 31,431 28.06
2022 29,562 26.39
2023 25,468 22.74
2024 26,914 24.03
Average [2] 27,154 24.24
Note: Hydrant meter demand is excluded from the average demand calculation.
When hydrant meter demand is included, the 2024 average demand is 25.05 MGD.
[1] Data is derived from the City of Corona water meter data. [2] The average of each year’s (2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, and 2024) average demand.
Demands from Hydrant Meters
Yearly meter demand shown in Table 4.2 excludes water demands associated with hydrant meters. A hydrant meter is a temporary meter connected to a fire hydrant and is typically used for temporary operation and maintenance activities, including main flushing, temporary construction water use, and sewer jetting and inspection. In most cases, the location of the hydrant meter is not specified; therefore it cannot be attributed to a specific land use designation or specific pressure zone. As a result, in Sections
4.3.2. and 4.3.3. hydrant meter demand is assigned a separate designation. This is also discussed in Section 5.2.2.
Demand by Land Use
To further evaluate the City’s average water demand, meter-read data were analyzed based on land use type. This analysis provides a baseline of existing water use by aggregating the average-day demands of all meters assigned to each land use category. These averages form the foundation for projecting future water demands.
Each meter was assigned a land use classification through the meter information database and the GIS correlation process described earlier. This assignment allowed the calculated average-day demand for each meter to be grouped by land use. The resulting land-use-specific average demands can be used in future development projections, with the assumption that the designated land use types will remain generally consistent with the City’s General Plan.
Meters were evaluated both within City boundaries and within the City’s sphere of influence (SOI).
Twenty-six land use categories exist for meters located in the City, and eighteen exist for meters located in the SOI. These land use categories align with the land use designations maintained in the City’s planning documents.
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The total average demand for each land use type within the City is shown in Table 4.3, and the corresponding SOI values are summarized in Table 4.4. These tables present the aggregate sum of the average day demand for all meters in each land use type; they do not represent a per-meter or per-parcel average.
Table 4.3 – City of Corona’s Demand by Land Use
City of Corona Aggregate Sum of Average Demands
Land Designation 2024 Aggregate Average Demand [1]
Abbreviation Description MGD GPM AFY
C Commercial 1.66 1149.91 1854.82
CP Commercial/Professional 0.25 176.75 285.11
FC Flood Control 0.06 43.19 69.66
GI General Industrial 0.81 561.13 905.11
I Institutional 0.42 293.95 474.14
LI Light Industrial 0.82 570.68 920.51
AG Agriculture 0.12 81.70 131.79
R/R Rural Residential 0.43 299.37 482.89
E Estate Residential 2.07 1438.77 2320.75
LDR Low Density Residential 8.67 6020.47 9711.09
LMDR Low Medium Density Residential 2.25 1561.23 2518.29 MDR Medium Density Residential 1.71 1186.13 1913.23
HDR High Density Residential 0.37 254.31 410.21
MFR Multi-Family Residential 2.61 1809.47 2918.70
MFR-MH Multi-Family Residential-Mobile Homes 0.12 84.55 136.38 OS-P Open Space-Park 0.11 75.16 121.23
OS-R Open Space-Recreational 0.12 81.46 131.39
QP Quasi-Public 0.08 58.20 93.87
ROW Right of Way 0.02 13.22 21.32
VA Vacant 0.01 10.03 16.18
VC Vacant Commercial 0.04 29.86 48.16
VI Vacant Industrial 0.00 0.16 0.25
VR Vacant Residential 0.06 38.41 61.95
Other Primarily areas under development 0.00 2.14 3.45
Total 22.81 15840.25 2550.48
Note: MGD values are rounded to two decimals; GPM and AFY are calculated from unrounded MGD. Rows showing 0.00 MGD represent very small demands. Aggregate totals are approximate and may differ slightly from the sum of displayed values due to rounding adjustments.
[1] The total average demand (City of Corona’s boundary plus Sphere of Influence) totals to 24.03 MGD. This demand does not include hydrant meter demand. See Section 4.3.1.
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Figure 4.2 – City of Corona’s Demand (AFY) by Land Use
C, 1854.82
CP, 285.11
FC, 69.66
GI, 905.11
I, 474.14
LI, 920.51
R/R, 482.89 AG, 131.79
E, 2320.75
LDR, 9711.09
LMDR,
2518.29
MDR,
1913.23
HDR, 410.21
MFR, 2918.70
MFR-MH, 136.38
OS-P, 121.23
OS-R, 131.39
QP, 93.87
ROW, 21.32
VA, 16.18
VC, 48.16
VI, 0.25
VR, 61.95
Other, 3.45
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Table 4.4 – Sphere of Influence Demand by Land Use
Sphere of Influence Aggregate Sum of Average Demands
Land Designation 2024 Aggregate Average Demand [1]
Abbreviation Description MGD GPM AFY
VLDR (SOI) Very Low Density Residential 0.05 37.24 60.07 LDR (SOI) Low Density Residential 0.04 27.80 44.85
MDR (SOI) Medium Density Residential 0.26 178.88 288.54 HDR (SOI) High Density Residential 0.04 28.43 45.86
CR (SOI) Commercial Retail 0.04 31.10 50.16
LI (SOI) Light Industrial 0.04 24.55 39.61
BP (SOI) Business Park 0.00 1.53 2.47
RR (SOI) Rural Residential 0.00 1.03 1.66
RM (SOI) Rural Mountainous 0.02 11.84 19.11
OS-MIN (SOI) Conservation 0.05 38.09 61.44
RC-EDR (SOI) Rural Community-Estate Density
Residential 0.03 17.60 28.38
RC-VLDR (SOI) Rural Community-Very Low Density
Residential 0.16 114.47 184.64
RC-LDR (SOI) Rural Community-Low Density Residential 0.47 327.33 527.98 Other (SOI) Primarily areas under development 0.01 5.58 8.99 Total 1.22 845.48 1,363.76
Note: MGD values are rounded to two decimals; GPM and AFY are calculated from unrounded MGD. Rows showing 0.00 MGD represent very small demands. Aggregate totals are approximate and may differ slightly from the sum of displayed values due to rounding adjustments.
[1] The total average demand (City of Corona’s boundary plus Sphere of Influence) totals to 24.03 MGD. This demand does not include hydrant meter demand. See Section 4.3.1.
Figure 4.3 – Sphere of Influence Demand (AFY) by Land Use VLDR (SOI), 60.07
LDR (SOI), 44.85
MDR (SOI), 288.54
HDR (SOI), 45.86
CR (SOI), 50.16
LI (SOI), 39.61
RR (SOI), 1.66
RM (SOI), 19.11
OS-MIN (SOI), 61.44 RC-EDR (SOI), 28.38
RC-VLDR (SOI),
184.64
RC-LDR (SOI), 527.98
Other (SOI), 8.99
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The water meter-read data show that residential customers, including rural community, represent the majority of water deliveries. Combined potable water delivery to Single-Family and Multi-Family residential land uses accounted for approximately 81 percent of all water delivered within the City in 2024, which is consistent with the City’s predominantly residential character.
Demand by Pressure Zone
In addition to analyzing water deliveries by land use type, demands were also evaluated by pressure zone to understand how water use is distributed across the City’s hydraulic system. This evaluation provides insight into zone-level loading conditions and supports the calibration and application of the hydraulic model.
The City of Corona operates seven primary pressure zones (725, 905, 1020, 1060, 1220, 1380, and 1640) with several subzones that operate at hydraulic grades similar to their parent zones. Additional connections exist for service to the City of Norco and the Home Gardens community, though these areas are not treated as traditional City pressure zones for demand evaluation.
Metered water use was spatially assigned to the appropriate pressure zone using the GIS meterplacement methodology described in Section 4.2. The resulting average-day demands for each pressure zone are shown in Table 4.5, with corresponding spatial distribution illustrated in Figure 4.4. Pressure Zone 1320 is not shown because it represents the Temescal Valley Water District (TVWD) pressurereducing station connection and does not contain City-metered retail water demand.
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Table 4.5 – Average Demand By Pressure Zone
DEMANDS BASED ON METER BILLING DATA (YEAR 2024)
ZONE
Aggregate Average Demand
GPM MGD AFY
725 166.55 0.24 268.65
780 909.66 1.31 1,467.27
820 112.48 0.16 181.44
905 4,861.20 7.00 7,481.12
920 12.45 0.02 20.09
960 23.44 0.03 37.82
1020 925.72 1.33 1,493.19
1045 5.96 0.01 9.62
1060 3,039.18 4.38 4,902.20
1130 6.11 0.01 9.85
1136 58.39 0.08 94.18
1220 3,742.71 5.39 6,036.99
1235 31.77 0.05 51.24
1250 24.55 0.04 39.60
1310 32.50 0.05 52.42
1315 59.79 0.09 96.45
1380 1,927.62 2.78 3,109.25
1480 29.27 0.04 47.21
1640 716.38 1.03 1,155.52
Hydrant [1] 706.73 1.02 1139.96
Totals 17,392.48 25.05
[2] 28,054.07
[1] Hydrant locations are not assigned to specific zones. See Section 4.3.1. [2] Total flow without hydrant demand is 24.03 MGD.
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Figure 4.4 – Average Demand (AFY) By Pressure Zone
Pressure Zone 905 had the highest overall demand, consistent with its size and density. Pressure Zones 1220 and 1060 had the next highest levels of demand, each with approximately two-thirds to threefourths the volume of Zone 905. Demand increases in Zones 1380 and 1640 are expected over time as undeveloped land in the southern part of the City is built out. Demand in Zones 1060 and 1220, which are both largely built out, is expected to remain stable.
4.4. WATER PRODUCTION
The preceding sections summarized the distribution of water demand by land use and pressure zone. The following section presents an overview of the City’s water production, including groundwater extraction, treatment plant deliveries, monthly production patterns, and the relationship between production and demand.
The City’s water production is supplied through a combination of groundwater wells and treated surface water produced at the City’s water treatment facilities. Between 2016 and 2019, groundwater accounted for approximately 48 percent of total production. Of the groundwater extracted during this period, roughly 80 percent was treated at the Temescal Desalter prior to entering the distribution system.
For the 2016–2019 baseline period, the City’s average annual production from all sources was 32,048 acre-feet per year (AFY), or approximately 28.6 MGD. Monthly production followed expected seasonal patterns. January and February represented the lowest-demand months, averaging approximately 1,824 AF and 1,742 AF, respectively. Summer months exhibited the highest production, with August averaging 3,587 AF or approximately 38.2 MGD. Monthly production values for the 2016–2019 period are provided in Table 4.6, along with the corresponding four-year monthly averages. 725, 268.65 780, 1467.27
820, 181.44
905, 7841.12
920, 20.09
960, 37.82
1020, 1493.19
1045, 9.62
1060, 4902.20
1130, 9.85
1136, 94.18
1220, 6036.99
1235, 51.24
1250, 39.60
1310, 52.42
1315, 96.45
1380, 3109.25
1480, 47.21
1640, 1155.52
Hydrant, 1139.96
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Beginning in 2020, water production continued to reflect a comparable split between groundwater and treated surface water. Between 2020 and 2024, groundwater contributed approximately 47 percent of annual production, with about 70 percent of that groundwater treated at the Temescal Desalter before entering the distribution system. During this more recent period, the City’s average annual production was 32,419 AFY, or approximately 29.0 MGD.
Production reached its highest level during the entire 2016–2024 timeframe in 2020, when the City produced 34,245 AFY (30.6 MGD). Production remained elevated through 2021 before decreasing in 2022–2024 as water use patterns began returning closer to long-term historical norms. Seasonal variability remained consistent with the earlier period, with January averaging 1,985 AF and August averaging 3,533 AF (37.7 MGD) for the 2020–2024 period. Monthly water production for these years is also shown in Table 4.7.
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Table 4.6 –Water Production by Month (AF), 2016 - 2019
Month 2016 2017 2018 2019 Average [1]
January 1,746 1,491 2,150 1,908 1,824
February 1,993 1,362 2,235 1,379 1,742
March 2,024 2,173 2,007 1,689 1,974
April 2,392 2,733 2,718 2,571 2,604
May 2,659 3,066 2,918 2,551 2,798
June 3,067 3,259 3,200 3,009 3,134
July 3,434 3,591 3,718 3,475 3,555
August 3,463 3,459 3,704 3,723 3,587
September 3,111 3,201 3,313 3,378 3,251
October 2,780 3,135 2,926 3,141 2,996
November 2,384 2,579 2,602 2,573 2,535
December 1,906 2,578 1,973 1,743 2,050
Total (AFY) 30,958 32,628 33,465 31,140 32,048
Note: Based on City of Corona’s Annual Production Recapitulation Data [1] The average of each month from the years 2016 to 2019.
Table 4.7– Water Production by Month (AF), 2020 - 2024
Month 2020 2021 2022 2023 2024 Average [1]
January 2,072 2,211 2,095 1,655 1,891 1,985
February 2,223 2,078 2,209 1,853 1,514 1,975
March 2,005 2,238 2,612 1,634 1,807 2,059
April 2,068 2,795 2,726 2,164 2,069 2,364
May 3,223 3,111 3,025 2,524 2,726 2,922
June 3,360 3,346 3,154 2,704 2,953 3,103
July 3,655 3,611 3,450 3,334 3,387 3,487
August 3,735 3,647 3,504 3,208 3,572 3,533
September 3,455 3,308 3,127 2,892 3,268 3,210
October 3,275 2,886 2,817 2,816 3,037 2,966
November 2,623 2,668 2,279 2,526 2,594 2,538
December 2,550 2,026 2,035 2,246 2,521 2,275
Total (AFY) 34,245 33,924 33,031 29,555 31,338 32,419
Note: Based on City of Corona’s Annual Production Recapitulation Data [1] The average of each month from the years 2020 to 2024.
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4.5. RECONCILIATION OF DELIVERIES AND PRODUCTION
Water deliveries discussed in Section 4.3. represent the volume of water recorded at customer meters— water taken out of the distribution system. The other side of the system balance is the volume of water produced at the City’s water treatment facilities and groundwater wells, as discussed in Section 4.4.
Ideally, total system production would equal total system deliveries. However, differences between these two values are expected due to unavoidable system losses, meter inaccuracies, and operational practices.
Water loss is the difference between the amount of water produced and the amount of water delivered.
Losses may result from distribution system leaks, illegal connections, unmetered fire use, meter calibration drift, data reporting inaccuracies, or other operational factors. Industry practice considers water losses of less than 5 percent to be acceptable for a well-maintained municipal water system. Losses below 3 percent are considered excellent and indicative of a highly efficient system.
The City performs annual water audits to quantify total production, billed consumption, and unbilled authorized uses. These audits form the basis of the loss estimates presented in Table 4.8 and Table 4.9.
The City’s water losses have steadily declined over time, decreasing from approximately 9.5 percent in FY 2015/2016 to 4.9 percent in FY 2018/2019. This improvement aligns with industry expectations for systems with ongoing meter replacement programs and pipeline rehabilitation activities.
From FY 2019/2020 through FY 2023/2024, losses remained consistently below the 5 percent benchmark, ranging between 3.26 percent and 4.17 percent, further indicating stable system performance and continued reliability in the City’s distribution network.
Methodology
The reconciliation process compared total annual demands (based on the meter-read database) to total annual water production (based on flow data from treatment facilities, groundwater wells, and import meters). For each fiscal year, the following values were compiled:
1. Total Water Production – Sum of all sources entering the distribution system, including treatment plants, groundwater wells, and imported water, minus water exported to other agencies.
2. Billed Authorized Consumption – Sum of all metered customer consumption, aggregated from the City’s billing database.
3. Unbilled Authorized Consumption – Hydrant use, system flushing, construction meters, and other approved non-revenue uses.
4. Calculated System Losses – Difference between total production and the sum of billed and unbilled authorized consumption.
This methodology is consistent with AWWA M36 water auditing procedures and reflects standard practice among California water purveyors. Loss percentages were calculated by dividing total system losses by total system production.
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The results of these analyses for fiscal years 2015/2016 through 2023/2024 are summarized in Table 4.8 and Table 4.9, which presents total production, total recorded demand, total calculated loss, and the corresponding loss percentage for each year.
Table 4.8 – Water Demand and Inefficiencies (AFY), 2016 - 2019 2015/2016 2016/2017 2017/2018 2018/2019 Average
Total Demands[1] 26,364 27,023 30,217 27,570 27,794
Total Production [1] 29,138 28,856 31,499 28,988 29,620 Water System Inefficiencies[1] 2,774 1,834 1,282 1,419 1,827 Water System Inefficiencies (%) 9.52% 6.35% 4.07% 4.89% 6.21% [1] Based on Water Audits
Table 4.9 – Water Demand and Inefficiencies (AFY), 2020 - 2024 2019/2020 2020/2021 2021/2022 2022/2023 2023/2024 Average Total Demands[1] 29,088 31,050 30,452 26,233 26,196 28,604 Total Production [1] 30,196 32,339 31,477 27,163 27,337 29,702 Water System
Inefficiencies[1] 1,108 1,289 1,025 930 1,141 1,099
Water System
Inefficiencies (%)
3.67% 3.99% 3.26% 3.42% 4.17% 3.70%
[1] Based on Water Audits
4.6. RECLAIMED WATER USE
Reclaimed water provides an opportunity to reduce the City’s potable water demand by converting selected potable-metered accounts, primarily irrigation and agricultural users, to the reclaimed water distribution system. Any such conversion requires expansion of the City’s reclaimed water infrastructure and must comply with the State of California’s Title 22 Water Recycling Criteria, which require tertiary treatment for all landscape irrigation uses. Reclaimed water used for irrigation may serve City parks, schools, roadway medians, golf courses, commercial landscaping, and other large irrigated parcels. A detailed description of reclaimed water demand is included in Section 3.6.
Based on the 2018 Reclaimed Water Master Plan (RWMP), in 2018, the reclaimed water distribution system delivered an average of 1,411 gpm (2,276 AFY) to end users. These users included irrigation for 26 City parks, 17 schools, and numerous commercial, industrial, and multifamily developments. As identified in the 2018 RWMP, additional reclaimed water demand could be realized through the conversion of properties adjacent to existing or planned reclaimed water pipelines. Potential future irrigation-use conversions were estimated at 139.9 gpm (226.5 AFY) from adjacent commercial, industrial, and multifamily parcels. Further expansion of reclaimed water pipelines could ultimately add 735.2 gpm (1,185.5 AFY) of additional reclaimed water demand.
At the time of the 2018 RWMP, direct potable reuse (DPR) was not evaluated in detail due to evolving statewide regulations. As described in Section 3, California has since adopted a statewide DPR regulatory framework. Any future consideration of DPR would require additional engineering analysis, regulatory coordination, and long-term planning.