Board certifies environmental report for Pure Water Southern California water reuse program

A major wastewater reuse initiative in Southern California reached a key milestone Feb. 10.

The Metropolitan Water District of Southern California unanimously certified the Final Environmental Impact Report (EIR) for Pure Water Southern California, a program that would purify and reuse treated wastewater currently discharged to the ocean from the Los Angeles County Sanitation Districts’ A.K. Warren Water Resource Facility in Carson.

This certification concludes more than five years of environmental review, technical analysis, and public input, advancing what could become one of the world’s largest water recycling programs. In 2023, California issued $80 million to Pure Water Southern California to advance the initiative, and around that same time, Brown and Caldwell and AECOM signed on in a joint venture for project and program management.

The approval completes extensive environmental analysis and clears the way for the board to consider future decisions on project phasing, funding, design, and construction, including regional infrastructure such as 60 miles of conveyance to support purification facilities and distribution pipelines in the region.

At full scale, the project is designed to produce up to 150 million gallons of purified water per day, which is enough to meet the needs of 1.5 million people, offering wastewater utility professionals and engineers a large‑scale example of indirect potable reuse and regional supply resilience.

“Recognizing that climate change presents serious challenges to our imported water supply, Metropolitan began development of Pure Water Southern California more than a decade ago as a drought-resistant sustainable local supply of water,” said Vice Chair Nancy Sutley. “Completion of the environmental review is a major milestone that will allow our board to evaluate next steps to advance the program.”

During the environmental review process, the project team identified potential construction and operational impacts tied to the proposed purification facilities and regional distribution pipelines. The Final EIR includes responses to all public comments and proposes mitigation measures where feasible.

“Under the leadership of Metropolitan Board Chair Adán Ortega, Pure Water Southern California has been grounded in strong partnerships and consensus. From the Los Angeles County Sanitation Districts, groundwater basin managers and our member agencies to the Central Arizona Project and Southern Nevada Water Authority, this project has been sustained by the support of partners who see the promise in a resilient local supply of recycled water,” said General Manager Shivaji Deshmukh.

Deshmukh also highlighted the importance of advancing Pure Water California through an inclusive and transparent process, and took pride in the relationships that have been fostered through the process thus far. 

“That commitment will continue as the project develops," Deshmukh said.

The board will evaluate next steps for implementing the project within its Climate Adaptation Master Plan for Water and upcoming biennial budget deliberations, determining how this new wastewater‑derived supply will fit into the region’s long‑term drought and climate resilience strategy.