County Moves to Treat Tijuana River Pollution
The San Diego County Board of Supervisors voted Tuesday to launch the Tijuana River Capture and Cleanup Initiative, approving $1.8 million to begin designing a treatment system that would capture and clean sewage from the river before it enters U.S. communities. The vote was 4-1, with Supervisor Joel Anderson opposed.
The initiative directs the county's chief administrative officer to begin an 18-month project development and engineering analysis, funded through the county's Unlocked Reserves Framework, according to a county staff report. It also converts the board's ad hoc subcommittee on the crisis into a standing committee with permanent oversight.
"We need to capture all of this waste, all this pollution, and we need to treat it before it gets into our rivers, before it gets near our schools, before it gets to our beaches," Board Chair Terra Lawson-Remer said.
The proposed treatment system would be separate from the existing South Bay International Wastewater Treatment Plant, operated by the U.S. section of the International Boundary and Water Commission. That plant treats wastewater that Mexico captures and conveys to it, but does not treat polluted flows that enter the Tijuana River itself and cross the border untreated, according to Chair Pro Tem Paloma Aguirre.
"When they talk about the 100% solution, they're talking about waiting for Mexico to fix it," Aguirre told the board, referring to a federal upgrade plan for the existing plant. "I have never in my entire life heard of a body of government depending on a different country to bring health, safety and welfare (to its own people), which is our responsibility to our constituents."
Funding and Next Steps
The initiative's long-term funding could come from a proposed countywide sales tax measure headed for the November ballot. The measure, titled "Protect San Diego County Health and Safety Act," would raise the countywide sales tax rate from 7.75% to 8.25%. It is projected to generate $360 million in new revenue in its first year, with 22.5% dedicated to Tijuana River Valley sewage mitigation.
Aguirre said that if approved by voters, the measure would generate about $80 million annually for Tijuana River solutions, which the county could use to bond for up to $1 billion in infrastructure funding. Lawson-Remer said the annual tax revenue could fund $700 million to $1 billion in bonds needed to build sewage treatment facilities.
The initiative requires that every step return to the Board of Supervisors for public review before advancing, Aguirre said.
Saturn Boulevard Hot Spot
The board also unanimously approved a separate measure allocating $4 million to advance design, environmental review and permitting for a permanent box culvert project at Saturn Boulevard, where hydrogen sulfide levels have reached 16 times the state air quality standard. Preliminary estimates put the permanent project's construction cost at roughly $23 million.
The work will proceed alongside a $2.5 million interim pipe-extension project already underway, with construction of the permanent project anticipated in 2027.
Perspectives on the Problem
Supervisors offered differing views on the source of the pollution and the best path forward.
Supervisor Jim Desmond said, "I would like to see Mexico stand up and finally fix the source of this issue... This is Mexico's fault."
Anderson said he wanted to see a formal coalition of affected cities before the county moved forward, and suggested leveraging water sales to Tijuana through the Otay Water District as negotiating leverage. Lawson-Remer countered, "We can't wait for all our little cities and all our counties and everybody to agree before we act."
Vice Chair Monica Montgomery Steppe said the action "lays the groundwork to build a locally controlled treatment system on the San Diego side of the border."
The board heard public comment from 18 speakers, along with more than 200 written comments on the two items. Sarah Davidson of the Surfrider Foundation's Clean Border Water Now program said the county's southernmost beach at Imperial Beach had been closed 1,728 consecutive days.
Background of the Crisis
Sewage from Tijuana flows into Imperial Beach, Coronado and other parts of southern San Diego County, sickening swimmers and surfers, forcing beach closures and threatening Navy SEALs training in Coronado. The river emits airborne toxins including noxious hydrogen sulfide gas, which causes asthma, headaches and other ailments in neighboring communities.
Wastewater treatment plants in the U.S. and Mexico have failed over the past decade, releasing hundreds of millions of gallons of raw sewage into the river. The federal government has dedicated about $650 million to repair and replace aging wastewater infrastructure, and Lawson-Remer noted the existing South Bay plant received more than $650 million in congressional funding for capacity upgrades.
According to a county staff report, more than 200 billion gallons of polluted water crossed into the U.S. through the Tijuana River between 2018 and 2026. Researchers at UCSD Scripps Institution of Oceanography estimate water pollution causes roughly 34,000 illnesses annually in Imperial Beach alone. Aguirre said the county has distributed 13,000 air purifiers, with 17,000 more planned, and has expanded air and water monitoring.
The treatment process could involve advanced water purification, which removes nearly all contaminants using techniques such as ultrafiltration membranes, reverse osmosis, advanced oxidation, ultraviolet light and disinfection, said Natalie Mladenov, an engineering professor at San Diego State University.
"We can't control what happens across the border, but we can control what we do on our side of it," Aguirre said. "We will continue to pressure Washington and Mexico, but we will set the pace. We're done waiting for someone else's timeline."
Lawson-Remer said the initiative reflects years of unmet promises to South Bay communities. "Managing this crisis is not the same as solving it," she said. Addressing legal concerns about the county's liability, she said, "It would be a really sad day if you don't do the right thing because you're scared of doing the right thing."
Supervisors described the effort as a chance for a permanent solution in an "aggressive timeframe."