Santa Monica’s City Council unanimously endorsed an updated water strategy that combines expanded conservation and local water recycling with potential regional partnerships. The vote authorizes city staff to begin formal talks with Los Angeles and the Metropolitan Water District of Southern California, as Santa Monica reassesses how much of its supply it can provide locally.
The updated plan steps away from a long-standing goal of meeting 99% of the city’s water needs from local sources, according to the Santa Monica Daily Press. The city now plans to maximize local recycling and expand conservation over the next five to 10 years, while relying on outside partners for the rest.
Water Resources Manager Sunny Wang told the Daily Press that the city should begin discussing partnerships now. The plan update was found exempt from state environmental review and sets the stage for Santa Monica to explore participation in two regional recycling programs that are still years from completion.
A Goal That Slipped Further Than Planned
Santa Monica's ambitions for water independence go back further than this year's vote. The city has long sought to reduce its reliance on imported water, according to the Santa Monica Daily Press.
The gap traces partly back to the COVID-19 pandemic, which cut conservation staffing in half and forced the city to defer recycled water and recharge well projects, per the outlet's reporting. A 2022 groundwater sustainability plan also clarified that the local basin's sustainable yield is only about 9,000 to 10,000 acre-feet a year, well below the roughly 15,000 acre-feet a year previously assumed. Without new conservation measures, the city faces a water-supply gap of up to 4,500 acre-feet by 2045 if new housing increases demand, the paper reported.
Local sources currently supply an estimated 80% to 85% of Santa Monica's demand, but that figure depends on two replacement wells at the Charnock Well Field becoming operational. The stakes of that dependence trace back three decades: Santa Monica shut down all five production wells at Charnock in 1996 after severe contamination from the gasoline additive MTBE, forcing the city to purchase up to 85% of its domestic water from the Metropolitan Water District, according to WesTech Engineering.
Purified Wastewater Headed for the Tap
Under the endorsed strategy, Santa Monica would send purified water through two additional treatment plants and blend it into the drinking supply at up to 10%, according to the Daily Press. The water would come from the city’s Sustainable Water Infrastructure Project, completed beneath the Civic Center parking lot in December 2022. City of Santa Monica project records say SWIP recycles up to 1 million gallons of municipal wastewater per day for permitted reuse, including future indirect potable reuse through aquifer recharge—a different pathway from the newly discussed proposal to blend water into the drinking supply. Separately, the same facility also treats stormwater and urban runoff, reducing pollution flowing into Santa Monica Bay.
Environmental advocate Mark Gold urged the city to pursue full direct potable reuse, which California regulations allow. The regulations were adopted by the State Water Resources Control Board in December 2023, approved by the Office of Administrative Law in August 2024 and took effect on October 1, 2024, according to California Water Views. Under the rules, a water system operating a direct potable reuse project must be designated a Direct Potable Reuse Responsible Agency; either the chief operator or a shift operator must be on site at all times, subject to a possible future alternative. The chief operator overseeing the treatment train must hold Grade T5 certification, and the chief operator at the advanced treatment facility must hold Grade AWT5 certification, according to guidance published by the California Water Environment Association.
How Santa Monica’s Reuse Plan Fits California’s Experience
California already has a large potable-reuse project with a different delivery route: the Orange County Sanitation District says its Groundwater Replenishment System, a collaboration with the Orange County Water District, began with a facility constructed in 2008 that supplied up to 70 million gallons per day. Its purified water is pumped to a groundwater basin, rather than blended directly into the drinking supply, according to OC San. The California State Water Resources Control Board says the state’s direct potable reuse regulations took effect on October 1, 2024. That statewide effective date does not itself authorize a Santa Monica project; any direct potable reuse proposal would also have to meet the operating and oversight requirements described above, according to the State Water Resources Control Board.
Betting on Regional Megaprojects, Years Away
Santa Monica's longer-term plan hinges on linking up with two of the largest water recycling efforts ever proposed in Southern California, both of which are expected to begin operating after 2035, per the Daily Press. The Metropolitan Water District's planned Pure Water Southern California facility could eventually produce up to 150 million gallons a day, and MWD currently runs a much smaller 500,000-gallon-per-day demonstration plant, according to Engineering News-Record.
Los Angeles's own Pure Water Los Angeles program is another regional water-recycling effort in Santa Monica's longer-term plans.
Desalination Shelved, For Now
Santa Monica also studied seawater desalination and treatment of contaminated groundwater beneath Santa Monica Airport, but placed both options on a wait-and-see list rather than active pursuit, per the Daily Press reporting. The cost comparison helps explain why: local groundwater currently costs about $900 per acre-foot and imported water runs about $1,500 per acre-foot, while desalination costs roughly $3,500 to $6,500 per acre-foot, according to the same account.
One emerging desalination technology did get a namecheck in the city's deliberations. Technology firm OceanWell's proposed “Water Farm 1” is a subsea reverse osmosis project targeting up to 60 million gallons per day by 2030, with a potential site a few miles off Malibu, according to a release carried by PR Newswire. The subsea pods operate 1,300 feet underwater, using natural hydrostatic pressure to cut energy consumption by 40% compared to onshore plants. A pilot of the OceanWell system is planned for February in Santa Monica Bay, but the Daily Press reported the technology is not ready for prime time. Design and construction contracts will return to the Santa Monica City Council, and a regional water-recycling deal is not expected anytime soon.
Conservation Savings Are Modest by Comparison
Against the scale of the megaprojects and supply gaps under discussion, the conservation measures the city is banking on look comparatively small: they are projected to save about 200 acre-feet a year over 20 years, per the Daily Press reporting. That is a fraction of the up-to-4,500-acre-foot gap the city could face by 2045.
The strategy also lands within a broader statewide push. Governor Gavin Newsom's California Water Supply Strategy sets targets to recycle 800,000 acre-feet of water per year statewide by 2030 and 1.8 million acre-feet by 2040, addressing roughly 1.5 million acre-feet of treated wastewater discharged into the ocean annually across California, according to Allen Matkins. Recycled water currently fulfills roughly nine percent of the state's total water demand.
The Daily Press report also noted broader strain on imported supplies feeding into the calculus: inflows into Lake Powell declined to 10.2 million acre-feet a year between 2020 and 2026, against 1922 Colorado River Compact water rights totaling more than 16 million acre-feet, and Hoover Dam's turbines are expected to shut down within the next year. For now, Santa Monica's bridge to the 2035 regional projects rests on the same local pillars it has leaned on for years — its existing groundwater wells and whatever conservation gains it can wring out along the way.
