San Diego Board Backs Billion-Dollar Cleanup for Polluted Tijuana River

After decades of pollution and years of beach closures, San Diego County supervisors have backed a sweeping $1 billion initiative to divert and treat raw sewage flowing through the Tijuana River. The board voted Tuesday to begin designing a new treatment plant that will clean contaminated water before it reaches local communities, schools, and beaches.

Sweeping Plan for Contaminated Water

The supervisors approved a $1.8 million allocation to design a system capable of capturing and purifying river water as it crosses the border. Spearheaded by Supervisors Paloma Aguirre and Terra Lawson-Remer, the Tijuana River Capture and Cleanup Initiative will be carried out in three phases. Officials noted that while existing facilities on both sides of the border capture and convey sewage, they lack the capacity to treat all the polluted water flowing directly through the river itself. As part of a broader $5.8 million strategic plan, which Aguirre emphasized involves putting local county funds directly to work on U.S. soil, officials are also converting the board’s ad hoc wastewater subcommittee into a standing oversight committee and pursuing emergency declarations alongside potential state legislation to accelerate permitting. An additional $8 million has been directed to the Department of Public Works to supervise the initial implementation phase. In a 4-1 vote, the board committed to the project. Supervisor Jim Desmond supported the measure, stating he hopes Mexico meets certain milestones in a federal agreement but that the county must plan for the worst-case scenario. Supervisor Joel Anderson cast the lone no vote, stressing the need to build a coalition before embarking on any new facility. "I don't believe we should be going this alone," Anderson said, suggesting the purchase agreement between the Otay Water District and the city of Tijuana could serve as leverage given the city's water needs. He argued the project falls outside their jurisdiction, though Chair Lawson-Remer countered that the initiative is designed to build that coalition and emphasized that officials do not want to wait. Additionally, the board unanimously authorized $4 million for immediate repairs at a critical sewage hotspot on Saturn Boulevard, where polluted air becomes aerosolized and drifts into residential areas.

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, said Board Chair Terra Lawson-Remer.

Funding the Cleanup

To finance the massive infrastructure project, officials are pushing for a half-cent county sales tax titled the Protect San Diego County Health and Safety Act. Scheduled for the November ballot, this measure could generate approximately $360 million annually. About $80 million of that revenue would be earmarked yearly for Tijuana River improvements, allowing the county to issue $700 million to $1 billion in bonds for construction.

Advanced Purification Technologies

Natalie Mladenov, an engineering professor at San Diego State University, outlined potential solutions ranging from standard EPA-compliant discharge to state-of-the-art advanced water purification. This process utilizes ultrafiltration membranes, reverse osmosis, advanced oxidation, ultraviolet light, and disinfection to strip out industrial chemicals, pesticides, pharmaceuticals, and raw sewage.

The accompanying $4 million authorization specifically covers design, environmental review, and permitting for a project aimed at replacing deteriorated rectangular conduits beneath Saturn Boulevard to improve water flow and reduce hazardous gas release. Located near the river, the road became a focal point after foul odor complaints spiked among residents in 2024. While the state standard for hydrogen sulfide is 30 particles per billion, local readings have reached 4,500 per billion. Once completed, the culvert replacement will allow water to move more freely through the channel, reducing the turbulence that releases harmful gases. The upgrade will also enhance flood protection, minimize road overtopping, and provide more reliable access to the Tijuana River Valley Regional Park.

Local California Context

This initiative directly impacts coastal San Diego communities that have suffered repeated beach closures and foul odors due to cross-border pollution. By taking control of the cleanup on the U.S. side, local officials aim to restore public health and revitalize local tourism and recreation.

The proposals have drawn strong backing from the local Sierra Club chapter and the YMCA. María Ortiz, a graduate student at the University of San Diego specializing in conflict resolution, highlighted the urgency of swift intervention, drawing parallels to her family’s rapid relocation during a past water toxicity crisis abroad to emphasize that decisive action remains achievable. Meanwhile, the U.S. Environmental Protection Agency recently released an update outlining several progress milestones in addressing the toxic sewage crisis along the border.

Background

The Tijuana River has been plagued by untreated wastewater for decades, recently ranking as the nation's second most endangered river according to American Rivers. After sixty years of unfulfilled promises, community skepticism regarding the issue is widely considered earned. While billions in federal funds have repaired aging plants along the border, significant pollution continues to bypass these facilities and flow directly into the ecosystem. Researchers from the University of California, San Diego previously investigated the Saturn Boulevard area and documented hydrogen sulfide concentrations measuring 4,500 times higher than typical urban baselines. Although supervisors recently approved $2.5 million for immediate pipe repairs expected to conclude next year, officials stress this addresses only an urgent health concern with pre-existing funding, leaving the larger investment gap for a lasting fix. Aguirre credited recent bilateral agreements but faulted both the Biden and Trump administrations for insufficient action, reiterating that dedicated funding, real partnerships, and years of work remain necessary to secure a permanent solution.

Conclusion

Supervisors emphasized an aggressive timeline to secure a permanent solution, stating they are finished waiting for external timelines.

Board Vice President Aguirre noted that dedicated funding and genuine cross-border alliances will require years of effort, while also calling on Governor Gavin Newsom or his successor to formally declare a state emergency to unlock faster resources. She affirmed continued collaboration with Mexican and federal authorities to mitigate discharge threats.

Voters will ultimately decide the fate of this critical environmental and public health investment this November.