Los Angeles officials gathered in North Hollywood this week to celebrate the completion of two groundwater treatment facilities designed to pull contamination out of a basin that has been polluted since World War II and turn it into drinking water for hundreds of thousands of homes. Mayor Karen Bass joined City Councilman Adrin Nazarian, Department of Water and Power officials, and state and federal regulators for a ribbon-cutting ceremony marking the finish of the North Hollywood Central and West facilities.
The two plants are part of the DWP's San Fernando Valley Groundwater Remediation Project, which as reported by MyNewsLA.com is one of Los Angeles's largest investments in local water infrastructure. Together, the two North Hollywood sites can treat up to 43 million gallons of contaminated groundwater daily, according to the outlet's reporting. Once the full project is running, the combined facilities are expected to process roughly 92 million gallons of water per day, enough to supply up to 400,000 Los Angeles homes a year.
A Contamination Problem Rooted in Wartime Industry
The pollution beneath the San Fernando Valley traces back to the 1940s, when commercial, defense, and manufacturing industries improperly disposed of industrial chemicals into local soil and aquifers, according to West Coast Aerial Photography. That unregulated disposal of toxic solvents left extensive underground chemical plumes across the basin. Large portions of the San Fernando Groundwater Basin were later designated a federal high-priority cleanup site, and the Environmental Protection Agency added the site to the federal Superfund National Priorities List in 1986 after widespread detection of volatile organic compounds across thousands of acres, per ToxicTargets.
The basin's cleanup has also drawn in corporate responsible parties. In 2018, the EPA issued administrative orders requiring Lockheed Martin and Honeywell International to execute and fund more than $21 million in groundwater extraction and treatment projects in the North Hollywood Operable Unit, targeting contaminants including 1,4-dioxane, hexavalent chromium, and trichloroethylene, according to Engineering News-Record.
Bold Climate Action, Officials Say
At the ceremony, Bass framed the milestone in broader terms. “Today is about bold climate action. It's about delivering results. It's about meeting the moment to protect our city, our people and our planet,” the mayor said, according to MyNewsLA.com's account of the event. Nazarian, who chairs the City Council's energy and environment committee, said Los Angeles will produce 70% of its water locally, the outlet reported.
The new facilities will pump, treat, and remove contaminants from groundwater so that it meets drinking water standards before entering DWP's water distribution system. The treated supply is expected to reduce the city's reliance on imported water and diversify its overall water portfolio, per the same reporting.
Funding Through State Grants and Local Investment
DWP received approximately $308 million in Proposition 1 grant funding, administered by the State Water Resources Control Board, to help pay for the project. That funding included $122 million for the North Hollywood Central facility, $46 million for the North Hollywood West facility, and $139 million for the still-unfinished Tujunga facility. The overall design and construction of all three treatment facilities carries an estimated total cost of $587 million, funded through a combination of municipal revenue, design-build contracts, and state water grants, according to the American Society of Civil Engineers.
The engineering behind the North Hollywood plants relies on advanced treatment trains that combine ultraviolet Advanced Oxidation Processes with Granular Activated Carbon filtration to destroy and absorb micro-pollutants. The North Hollywood Central facility alone features four UV reactors equipped with 384 lamps each, alongside 18 GAC vessels, the civil engineering group notes.
Why Los Angeles Is Betting on Its Own Aquifer
Los Angeles currently imports more than 70% of its water from sources including the Eastern Sierra, the Colorado River, and the Sacramento-San Joaquin Delta, leaving the city exposed to regional droughts and import cutbacks, according to CBS Los Angeles. Under California water law, the City of Los Angeles holds a historic pueblo right to the native groundwater and surface flows of the San Fernando Basin, a legal authority tracing back to Spanish and Mexican legal traditions recognized upon California's statehood, according to the Los Angeles Department of Water and Power. That right gives the city priority to store, extract, and manage water within the basin's underground reservoir.
A third facility is slated for completion in Tujunga in 2027, sitting directly adjacent to the 150-acre Tujunga Spreading Grounds, which capture local urban stormwater runoff to recharge the aquifer below. Once all three treatment facilities are operational, they will replenish Los Angeles groundwater that supplies drinking water to communities across the city.
The North Hollywood milestone also lands amid a leadership transition at DWP. Chief Executive Janisse Quiñones, who was confirmed in May 2024 to oversee the city's renewable energy and water infrastructure transition, announced earlier this year that she will step down in March 2026, as Hoodline previously reported.
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