years of consecutive drought, as well as in normal year conditions. This is discussed in Section 7 as well as Appendix D.
IRWD has evaluated its water shortage risk and determined that it has sufficient supply capabilities for a drought period that lasts five consecutive water years based on the driest five-year historic sequence. This Drought Risk Assessment was completed for the period 2026 through 2030. The results are presented in Section 7 as well as Appendix D. IRWD's water resource portfolio consists of imported water, groundwater, recycled water, and local surface water. IRWD has placed an emphasis on becoming less reliant on imported supplies. In fiscal year 2000-01, approximately 56% of IRWD’s total water supplies were from local sources; today, local supplies make up about 80% of IRWD’s supplies. IRWD has developed a comprehensive plan for stages of actions it would undertake to address frequent and severe periods of droughts. Its Water Shortage Contingency Plan includes six standard water shortage levels corresponding to progressive ranges of up to 10, 20, 30, 40, and 50 percent shortages and greater than 50 percent shortage. IRWD continues to invest in water use efficiency measures and sustainable water supplies that helped IRWD reduce its 2020 daily per capita use to 95 GPCD, well below its 2020 reduction target of 171 GPCD. IRWD continues to plan for emergency and catastrophic scenarios including the development of a regional Water System Risk and Resilience Assessment (2025), preparation of an Emergency Operations Plan (2025) and adoption of the regional Orange County Water and Wastewater Multi-Jurisdictional Hazard Mitigation Plan (MJHMP) in 2025. IRWD has invested in emergency storage in Kern County where excess water is stored during wet years for use in extended droughts, supply interruptions or other water shortage emergencies. IRWD has and will continue to regard water quality with paramount importance in protecting its water supply. IRWD owns and operates a state-of-the-art Water Quality Laboratory that is state certified and one of the best equipped water laboratories in southern California. IRWD’s water quality staff continuously monitors the water supply, conducting over a quarter of a million laboratory tests each year from water taken from over 100 sample points throughout the IRWD service area. IRWDs Water Quality Laboratory analyzes these samples to ensure that IRWD’s delivered water meets or exceeds all state and federal drinking water standards.
Future Challenges and Strategies to Manage Reliability Risk
Future challenges to water supply reliability may include drought, natural disasters, water quality concerns, and long-term effects of climate change. Although these challenges primarily present a risk to imported water supply reliability, IRWD has numerous strategies in place to manage reliability risk including:
ES - 3 IRWD – 2025 Urban Water Management Plan – Executive Summary and Lay Description
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