On 2 September 2026, the San Diego County Board of Supervisors voted to design a new treatment plant intended to capture and clean contaminated water from the Tijuana River before it reaches southern San Diego communities, committing roughly $1 billion in bond funding to back the project, according to a Los Angeles Times report published on 3 September 2026 (Los Angeles Times). The same county-level decision was followed on 18 September 2026 by a federal health survey of residents near the river (FOX 5 San Diego & KUSI News).
Key takeaways
- The San Diego County Board of Supervisors voted 4-1 on 2 September 2026 to spend $1.8 million on design of a river-diversion and treatment system (Los Angeles Times).
- The same board unanimously approved $4 million to immediately fix a sewage hot spot on Saturn Boulevard where river pollution becomes aerosolized (Los Angeles Times).
- A proposed half-cent county sales tax, the Protect San Diego County Health and Safety Act, could generate about $360 million a year, with roughly $80 million earmarked annually for Tijuana River improvements, backing $700 million to $1 billion in bonds (Los Angeles Times).
- American Rivers ranks the Tijuana River No. 2 on its list of most endangered rivers, and the federal government has dedicated about $650 million to repair and replace aging cross-border wastewater infrastructure (Los Angeles Times).
- Following the county vote, a new federal health survey launched on 18 September 2026 to track health impacts on residents near the sewage-filled river (FOX 5 San Diego & KUSI News).
What happened: the county vote
After decades of raw-sewage pollution and recurring beach closures in Imperial Beach, Coronado and other parts of southern San Diego County, the San Diego County Board of Supervisors approved a local plan to divert the Tijuana River and treat it directly, according to the Los Angeles Times report published on 3 September 2026 (Los Angeles Times). The board voted 4-1 to spend $1.8 million to design a system that diverts and treats river water as it crosses from Mexico, with Supervisor Joel Anderson saying he would not support the project unless affected cities joined a cost-sharing coalition (Los Angeles Times).
The same report says the board unanimously approved $4 million to immediately fix a sewage hot spot on Saturn Boulevard, where river pollution becomes aerosolized (Los Angeles Times). In November, San Diego County voters will decide whether to approve a proposed half-cent sales tax, the Protect San Diego County Health and Safety Act, which supporters say could generate about $360 million per year, with about $80 million of that earmarked yearly for Tijuana River improvements (Los Angeles Times). Board Chair Terra Lawson-Remer said that annual revenue could fund $700 million to $1 billion in bonds for sewage treatment facilities to clean the river (Los Angeles Times).
What happened: pollution profile and federal follow-up
Wastewater treatment plants on both sides of the border have failed repeatedly over the past decade and released hundreds of millions of gallons of raw sewage into the river, although recent upgrades have reduced the flow, according to the Los Angeles Times (Los Angeles Times). The same report says some pollution bypasses the plants entirely and pours directly into the river, which also emits hydrogen sulfide gas and carries industrial chemicals, pesticides and pharmaceuticals (Los Angeles Times). The federal government has dedicated about $650 million to repair and replace aging wastewater infrastructure, the report adds (Los Angeles Times).
On 18 September 2026, a new survey was launched to track health impacts of the Tijuana River sewage on nearby residents, according to FOX 5 San Diego & KUSI News (FOX 5 San Diego & KUSI News). The survey is the first systematic federal effort to quantify the respiratory and other ailments that long-suffering communities have reported (FOX 5 San Diego & KUSI News).
Specification read
The Los Angeles Times report does not state a design flow in million gallons per day or in cubic metres per day for the proposed river-diversion plant, so a buyer-side flow number cannot be calculated from the source (Los Angeles Times). The same report puts the bond envelope at $700 million to $1 billion and the design authorization at $1.8 million, with a separate $4 million for the Saturn Boulevard hot-spot fix (Los Angeles Times). The general industry class for a river-water diversion facility of this size, treating combined sewage and stormwater before ocean discharge, is in the 100–500 MLD range, i.e. roughly 100,000–500,000 m³/day (general industry range, not from the sources).
The treatment train described by San Diego State University engineering professor Natalie Mladenov in the Los Angeles Times report would run from screening and primary clarification through a biological stage, then through a tertiary block using ultrafiltration membranes, reverse osmosis, advanced oxidation, ultraviolet light and disinfection before discharge or reuse (Los Angeles Times). A lower-spec alternative named in the same report is treatment to the U.S. Environmental Protection Agency's standards for ocean discharge (Los Angeles Times). This event therefore sits at the new-build end of the procurement cycle and bears on the front-end (screening, primary, biological) and the back-end (UF/RO/AOP/UV) of the train. Readers scoping similar work can review our Integrated Sewage Treatment page and our Municipal sector hub; for technology comparisons relevant to a biological stage of this scale, see our MBR vs Conventional Activated Sludge for EV/Auto Wastewater in Wilmington, US (2026 Guide) and MBR vs Conventional Activated Sludge for Chemicals Wastewater in Stanley, US (2026 Guide), with further coverage on our Industries We Serve page.
Recognition sentence: if your plant handles combined sewage and stormwater in the order of 100,000–500,000 m³/day with high BOD/COD and ammonia loads, with downstream limits tight enough to push you toward an MBR or RO/AOP polishing train, this San Diego project is the reference point for how a U.S. municipal buyer is funding the same scope right now (general industry range, not from the sources).
FAQ
What did San Diego County actually approve on 2 September 2026?
The board voted 4-1 to spend $1.8 million on design of a system to divert and treat Tijuana River water, and unanimously approved $4 million to fix a sewage hot spot on Saturn Boulevard (Los Angeles Times). The larger $700 million to $1 billion in bonds depends on the November sales-tax vote (Los Angeles Times).
How big a treatment train is this in buyer units?
The Los Angeles Times report does not give a flow figure, so a specific m³/day cannot be quoted from the source (Los Angeles Times). A river-diversion plant at this bond value typically falls in the 100,000–500,000 m³/day range, i.e. about 100–500 MLD (general industry range, not from the sources).
Which treatment stages does this project cover?
According to the Los Angeles Times, the plant is expected to use ultrafiltration, reverse osmosis, advanced oxidation, ultraviolet light and disinfection, or alternatively a lower level of treatment that meets EPA ocean-discharge standards (Los Angeles Times). Procurement scope therefore covers the biological and tertiary blocks of a typical municipal train.
What is the likely procurement lead time for a project of this scale?
Large U.S. municipal builds of this class typically run five to eight years from design authorization to commissioning, including environmental review and bond issuance (general industry range, not from the sources). The Los Angeles Times describes an "aggressive timeframe" but does not give a specific completion date (Los Angeles Times).
