1 Table of contents 652

Draft 2025 Urban Water Management Plan

Learn more at irwd.com/doing-business/urban-water-management-plan.

Draft Urban Water Management Plan		1
Contact_Sheet		2
Executive Summary		13
Executive Summary and Simple Lay Description of the UWMP Findings		13
Urban Water Management Plan		13
IRWD Water Service Reliability		13
Hydrologic Conditions and Reporting Period		14
Findings of the 2025 UWMP		14
Section 1		17
Section 1 | Introduction		17
1.1 Urban Water Management Planning Act		17
1.2 Irvine Ranch Water District (IRWD)		17
1.3 Purpose and Importance: IRWD Water Resources Planning		18
1.4 UWMP Organization and Section Summaries		18
Section 2		21
Section 2 | Plan Preparation		21
2.1 Basis for Preparing a Plan		21
2.2 Public Water Systems		21
2.3 Regional Planning and Regional Alliance		22
2.4 Standardized Tables, Year, and Units of Measurement		22
2.5 Coordination and Outreach		24
Coordination with Wholesale Agencies		24
Coordination with Water Suppliers and the Community		25
Section 3		27
Section 3 | System Description		27
3.1 General Description		27
3.2 Service Area Boundaries		29
3.3 Population		31
3.4 Local Climate		31
3.5 Historic, Current and Projected Land Use		32
Land Use Major Changes Over Time		32
Land Use and Water Resource Planning		33
Section 4		37
Section 4 | Water Use Characterization		37
4.1 Description of Defined Water Use Sectors		38
4.2 Past, Current, and Projected Water Use by Sector		39
Estimating Future Water Savings		41
Water Use of Lower Income Households		42
Climate Change Considerations on Customer Water Use		42
4.3 Distribution Water System Losses		43
Section 5		44
Section 5 | SBX7-7 Baselines and Targets		44
5.1 2020 Water Conservation Mandate		44
5.2 Regional Alliance		45
Section 6		46
Section 6 | System Supplies		46
6.1 Purchased or Imported Water		47
Imported Potable Water		47
Imported Non-Potable Water		47
6.2 Groundwater		48
Basin Description		48
A. Orange County Groundwater Basin		49
IRWD Groundwater Production		49
A. Irvine Sub-Basin Pumping		49
B. Lake Forest Area Sub-Basin Pumping		50
Groundwater Sustainability Plan for the Orange County Basin		51
6.5 Wastewater and Recycled Water		55
Sewage Collection, Treatment, and Disposal		55
Recycled Water Direct Beneficial Uses		58
Current and Projected Use of Recycled Water		59
Optimizing Future Recycled Water Use – Recycled Water Projects		59
A. Dual Plumbed Buildings		60
B. Residential Landscaping		60
C. Commercial and Industrial Uses		60
D. Recycled Water Conversion Projects		61
6.6 Desalinated Water and Opportunities		62
6.7 Transfers and Exchanges		63
6.8 Supply From Storage		64
6.9 Other		64
6.10 Future Water Projects and Supplies		64
Existing Sources		66
6.12 Energy Intensity		68
Section 7		71
Section 7 | Water Supply Reliability and ………… Drought Risk Assessment		71
A. Recent IRWD Water Reliability Studies and Evaluations		71
B. Historic Drought Analysis		73
C. Water Supply Reliability Projections		73
IRWD Normal Year Projections		74
IRWD Single Dry Year Projections		74
IRWD Multiple Dry Year Projections		75
7.2 Water Service Reliability Assessment		77
A. Imported Water		77
B. Groundwater Supply		77
7.3 Water Quality		79
Groundwater Quality		80
Other Water Quality Considerations		80
Imported Water Quality		81
7.4 Drought Risk Assessment		81
Drought Risk Assessment Data Inputs and Methods		82
A. Total Water Use (Demands)		82
B. Total Supplies		83
Drought Risk Assessment Conclusions		84
A. Surplus and Shortfall without WSCP Actions		84
B. Planned WSCP Actions		84
Section 8		86
Section 8 | Water Shortage Contingency Plan		86
8.1 Overview of Water Shortage Contingency Plan		86
8.2 Summary of Sections and Requirements		87
8.3 Copy of DWR Tables		88
Section 9		94
Section 9 | Demand Management Measures		94
9.1 Demand Management Measure Implementation		94
A. Budget-Based Rate Structure		95
B. Revenue Stability		95
C. Price Signal to Reduce Water Waste		96
D. Rate Structure Results		96
9.2 Water Use Efficiency Programs and Resources		97
A. Programs		97
B. Workshops and Tours		98
C. Public Outreach and Social Media		98
D. Education Programs		98
E. Water Waste Prevention		99
F. Metering		100
G. Distribution System Loss		101
H. Water Efficiency Staffing		101
9.3 California Water Efficiency Partnership		101
References		107
Appendices		110
Appendix A- DWR Checklist		111
Appendix B- Reduced Reliance on the Delta		125
Appendix C- Outreach Letters		148
Appendix D- DWR Submittal Tables		165
Appendix E- Water Shortage Contingency Plan		189
Appendix F- Basin 8-1 Alternative		281
Appendix G- Orange County Demand Projection		577

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