MWD targets spring vote on $7.5B Sites Reservoir as state eases permit terms
West Basin Municipal Water District, California · Meeting date: September 9, 2026 · Published: September 10, 2026
A revised draft water rights permit has removed restrictive outflow mandates, clearing a path for the Metropolitan Water District to weigh final participation in the 1.5 million acre-foot Northern California storage project.
Key points
- The estimated cost of the Sites Reservoir has increased, with the Sites Authority asking participants to agree to an escalated cap of up to $7.5 billion.
- California's State Water Board recently removed a proposed 55% unimpaired delta outflow standard from the draft permit, protecting the project's yield.
- MWD expects a final water rights permit by early November, setting the stage for a board vote in the spring on whether to proceed.
- The district's planned 312,000 acre-foot share of the reservoir would yield an average of 30,000 to 40,000 acre-feet annually, accounting for a 20% to 30% loss moving through the Delta.
Full report
The Metropolitan Water District (MWD) is preparing for a pivotal spring vote on its participation in the Sites Reservoir project, following a major regulatory breakthrough that protects the proposed facility's water yield.
Speaking at a September 9, 2026, West Basin Municipal Water District meeting, MWD Manager of Bay Delta Programs Randall Nudek outlined recent changes to the project's draft water right permit. A revised draft issued by the State Water Resources Control Board removed a mandate that would have required the project to meet a 55% unimpaired delta outflow standard. Instead, the reservoir will operate according to the existing water rights standards of the State Water Project and Central Valley Project at the time operations begin. Nudek noted this change avoids significant impacts to the yield. The state board is scheduled to adopt the final water rights permit in early November.
MWD is considering a 312,000 acre-foot share of the 1.5 million acre-foot reservoir, representing 22% of its total capacity. While the district could draw down its entire share during a three-year drought, the average annual yield is projected at 30,000 to 40,000 acre-feet, factoring in a 20% to 30% conveyance loss as the water moves through the Delta to state pumping plants.
The regulatory progress comes as the project's price tag climbs. Nudek confirmed the current estimate stands between $6.2 billion and $6.8 billion in 2024 dollars. However, the Sites Authority will ask participants to agree to a funding cap of up to $7.5 billion to account for construction cost escalators.
Early procurement is already underway. Barnard Construction was selected for a $1 million preconstruction construction-manager-at-risk (CMAR) contract for the reservoir and roads, having negotiated a project labor agreement with the State Building and Trades Union. A separate CMAR contract for conveyance is targeted for release in early 2027.
MWD staff will present updated operations and modeling data this fall, followed by a review of funding agreements in the winter. The MWD board is expected to vote on an action letter to move forward with the project in the spring. If approved and kept to an ideal schedule, the estimated eight-to-ten-year construction process would conclude around 2034.
This summary was generated by AI based on the source document and may contain errors.
Source: Metropolitan Water District Representatives Caucus, West Basin Municipal Water District