Reports & Plans

The Water Policy and Resources Development Department is responsible for developing viable plans and initiatives to ensure reliability of the region’s water supplies. It plays an important role in reducing the region’s dependence on imported water by expanding the local water supply portfolio in an economically feasible manner. Through effective partnerships and innovative planning, the staff continues to demonstrate a proactive approach to water resource management.

West Basin develops three planning documents: The Urban Water Management Plan, the Drought Rationing Plan, and the Annual Water Use Report.

Urban Water Management Plan

The State of California, through the amended California Water Management Planning Act of 1983, requires all urban water suppliers to develop an Urban Water Management Plan (UWMP) every five years to demonstrate in detail how their agency manages its water supplies and demands under all hydrology conditions. The UWMP provides water supply planning projections for a 25-year period and identifies water supplies needed to meet existing and future demands.

2020 Urban Water Management Plan

Following a public hearing and meeting, the West Basin Board of Directors adopted the 2020 UWMP, effective July 1, 2021. The Board also adopted a 2021 Water Shortage Contingency Plan, which can be found in the 2020 UWMP link.

View West Basin’s 2020 Urban Water Management Plan
View 2020 UWMP Fact Sheet
View 2020 UWMP Executive Summary

Archived UWMP

Annual Water Supply and Demand Assessment

All California urban water suppliers that either provide more than 3,000 acre-feet of water annually or that serve more than 3,000 urban connections are required to conduct an Annual Water Supply and Demand Assessment (AWSDA) and to submit an Annual Shortage Report to the Department of Water Resources (DWR) on or before July 1 of each year.

Most recently, West Basin coordinated its 2022-2023 AWSDA development efforts with the Metropolitan Water District of Southern California (Metropolitan) and West Basin’s retail water suppliers. Since West Basin is exclusively dependent on Metropolitan for its imported water supplies, the data provided by Metropolitan’s preliminary AWSDA was used to help inform West Basin’s AWSDA. In turn, West Basin provided data from its preliminary AWSDA to its retail agencies to support retailer AWSDA assessment and shortage report efforts.

For this year’s AWSDA process, West Basin submitted preliminary and final versions of its 2022-2023 AWDSA to DWR by the required statutory deadlines of June 1, 2022, and July 1, 2022, respectively.

The results of the district’s 2022-2023 AWSDA demonstrate there are no expected shortages in the West Basin service area for the period of July 1, 2022-June 30, 2023.

View West Basin’s 2022-2023 Annual Shortage Report.

2022-2023 Annual Shortage Report

West Basin will continue to closely monitor key statewide and local water conditions, while coordinating with its retail agencies and Metropolitan to evaluate critical water supply reliability metrics for the upcoming evaluation period.

More information regarding AWSDAs be found on the California DWR website.

Drought Rationing Plan

The West Basin Drought Rationing Plan (DRP) was in effect from 2009-2011 (under the name Water Shortage Allocation Plan) and again in 2014-2015.

The methodology used to implement the DRP:

Metropolitan Water District’s (MWD) Board of Directors approved the amended Water Supply Allocation Plan in March 2015, which is based on a guiding principle developed almost 15 years prior as part of their Water Surplus and Drought Management Plan.

According to the principle, “Metropolitan will encourage storage of water during periods of surplus and work jointly with its member agencies to minimize the impacts of water shortages on the region’s retail consumers and economy during periods of shortage.”

Fairness in allocation and minimizing regional hardship to retail water consumers remained central themes in the development of a specific formula for allocating shortages across Southern California. The formula uses different adjustments and credits to balance impacts of shortage at the retail level, where local supplies can vary dramatically, and provide equity on the wholesale level among member agencies. It also attempts to account for the growth in demand, local investments, changes in local supply conditions, the reduction in potable water demand from recycled water, and the implementation of water conservation programs.

Based closely on MWD’s methodology, West Basin’s Drought Rationing Plan model, adopted by the Board of Directors in April 2009 and amended in March 2015, determines each customer agency’s share of West Basin’s allocation from MWD.

West Basin Drought Rationing Plan

Water Use Report

Every year West Basin develops the Water Use Report to inform its customer agencies, Board of Directors and key stakeholders of the service area’s annual water usage as well as its customer agency’s retail usage. It is designed to be a water resource reference tool summarizing the following information:

    • 10-year historical water use (imported, recycled, and groundwater)
    • Water use by month over the most recent fiscal year
    • Tier 1 and commitment amount
    • Potable meter connection data
    • Imported & recycled water rates & charges
    • Contact information
    • Recycled water connections

Water Use Report 2022-2023

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