The San Diego County Board of Supervisors voted 4-1 on 2 September 2026 to launch a new, locally controlled sewage treatment system on the U.S. side of the border, and unanimously backed a separate $4 million package to plan a permanent replacement for failing box culverts beneath Saturn Boulevard NBC 7 San Diego San Diego Union-Tribune.
Key takeaways
- Supervisors approved the Tijuana River Capture and Cleanup Initiative 4-1, with Joel Anderson opposed, and passed the Saturn Boulevard package unanimously San Diego Union-Tribune.
- The capture and cleanup work begins with an 18-month project development and engineering analysis, funded by $1.8 million from the county's Unlocked Reserves Framework San Diego Union-Tribune.
- The Saturn Boulevard package puts $4 million toward design, environmental review and permitting for a permanent box culvert, running alongside a $2.5 million interim pipe extension expected to be built in 2027 San Diego Union-Tribune.
- Sponsors Aguirre and Lawson-Remer are requesting $5.8 million in local county funds to start work on U.S. soil, and pointed to recent U.S.–Mexico agreements while faulting federal administrations and Governor Newsom for inaction NBC 7 San Diego.
- Long-term financing could be backed by a November ballot sales tax measure that would raise the county rate from 7.75% to 8.25%, generating $360 million in its first year with 22.5% earmarked for Tijuana River Valley sewage mitigation, and Aguirre said it could bond up to $1 billion San Diego Union-Tribune.
What happened
The board acted on a package put forward by Supervisor Paloma Aguirre, board chair pro tem, and Board Chair Terra Lawson-Remer NBC 7 San Diego. Their Tijuana River Capture and Cleanup Initiative will be carried out in three phases and is intended to intercept and treat polluted water flowing through the Tijuana River itself, rather than relying solely on Mexico-side capture and the existing South Bay International Wastewater Treatment Plant NBC 7 San Diego San Diego Union-Tribune.
"Existing facilities on both sides of the border keep sewage out of the Tijuana River by capturing it in Mexico and conveying it to treatment," Aguirre and Lawson-Remer wrote, adding: "But those systems do not capture everything, and none of them have the capacity to treat all of the polluted water flowing through the river itself" NBC 7 San Diego. The measure also converts the board's ad hoc subcommittee on the crisis into a standing committee with permanent oversight San Diego Union-Tribune.
Anderson cast the lone no vote, saying the county should first build a coalition with affected cities and warning that high project costs make a solo effort risky: "I don't believe we should be going (this) alone," he said, adding, "My concern is this is not our lane" NBC 7 San Diego. He suggested leveraging the Otay Water District's water purchase agreement with Tijuana as negotiating leverage, and noted that the city of Tijuana cannot grow without more water San Diego Union-Tribune. Supervisor Jim Desmond supported both measures but said the underlying responsibility sits with Mexico NBC 7 San Diego.
The second item, a $4 million allocation for design, environmental review and permitting, targets a permanent box culvert project beneath Saturn Boulevard, near a "hot spot" where a UC San Diego team recorded hydrogen sulfide levels 4,500 times higher than typical urban background in 2024 NBC 7 San Diego. Union-Tribune reporting put the same readings at 16 times the state air quality standard San Diego Union-Tribune. According to the board letter, the replacement would "allow water to move more freely through the channel, reducing the turbulence that releases harmful gases into the air," while also improving flood protection and park access NBC 7 San Diego. A $2.5 million interim pipe-extension project, already approved, is expected to reach completion next year, with permanent culvert construction anticipated in 2027 San Diego Union-Tribune.
The board heard from 18 speakers and reviewed more than 200 written comments on the two items combined San Diego Union-Tribune. Supporters included the local Sierra Club chapter, the YMCA, the Surfrider Foundation's Clean Border Water Now program and the San Diego Regional Chamber of Commerce, with Sarah Davidson of Surfrider noting the southernmost county beach had been closed 1,728 consecutive days San Diego Union-Tribune NBC 7 San Diego. One District 5 resident pushed back, arguing that $600 million in EPA funding has already been proposed and that the Trump administration had secured Mexican diversion actions, telling supervisors "the county's asking the poisoned to pay for this" NBC 7 San Diego. Aguirre said the new system is "a long-term solution that gives us control of our own future," and Lawson-Remer added, "The time has come to end this environmental injustice" NBC 7 San Diego.
Specification read
The two items together move the county from planning into project development on a river-pollution interception scheme and a culvert replacement. No daily flow, BOD or population-equivalent figure for the new U.S.-side treatment plant was disclosed in either source; the first 18 months are an engineering and siting study, not a procurement San Diego Union-Tribune. For a river-water interception duty of the size Aguirre has linked to a possible $1 billion bonding envelope, a typical train would run screening and grit removal, primary clarification, a biological stage suited to variable-strength sewage (commonly A2O, MBR, MBBR, SBR or UASB depending on footprint and effluent targets), followed by tertiary filtration, disinfection, and, where discharge limits demand it, DAF thickening and a ZLD or high-recovery reverse osmosis polishing step (general industry range, not from the sources). The Saturn Boulevard package, by contrast, is conveyance work, not treatment: replacing a failing box culvert so water passes through the channel with less turbulence and lower hydrogen sulfide off-gassing, with design and permitting funded at $4 million and a separate $2.5 million interim pipe extension in construction San Diego Union-Tribune NBC 7 San Diego.
If your facility receives a comparable river-water or wet-weather feed of a few tens of MLD, with high and variable BOD/COD, a tidal-clogging and sulfide-prone outfall, and a regulator pressing you for a local, controllable solution, this is the stage you will be pricing first: the project development and engineering study, not the bioreactor. Plant managers and procurement leads tracking Municipal interceptor and Integrated Sewage Treatment opportunities should treat the 18-month analysis as the gateway to design packages, siting decisions, and ultimately a build that could be financed through a sales-tax-backed bond of up to $1 billion San Diego Union-Tribune. The county's broader project portfolio, including the kind of conveyance and treatment infrastructure described here, sits within the wider Industries We Serve landscape where packaged and integrated systems are typically evaluated. For a buyer's view of how similar effluent trains are scoped and procured, see this Effluent Treatment Plant in Melbourne: 2026 Buyer's Engineering Guide and this How to Choose a Packaged MBR STP for a Hotel in Kuala Lumpur (2026 Buyer's Guide).
FAQ
What exactly did the San Diego County Board of Supervisors approve on 2 September 2026? A 4-1 vote to launch the Tijuana River Capture and Cleanup Initiative, starting with an 18-month project development and engineering analysis funded by $1.8 million from the county's Unlocked Reserves Framework, and a unanimous vote to put $4 million into design, environmental review and permitting for a permanent Saturn Boulevard box culvert San Diego Union-Tribune.
How big could this treatment plant be, and is there a flow or capacity number? Neither outlet reported a flow rate, BOD/COD load, or population equivalent for the new U.S.-side plant. Aguirre has tied long-term financing to a possible sales-tax-backed bond of up to $1 billion, but no MLD figure was disclosed in the sources San Diego Union-Tribune. As a class reference, river-water interception projects at this scale are typically scoped in the tens of m³/day range (general industry range, not from the sources).
When will the Saturn Boulevard permanent culvert actually be built? Construction is anticipated in 2027, after the $4 million design, environmental review and permitting phase, and it will run in parallel with a $2.5 million interim pipe-extension project already underway San Diego Union-Tribune.
How is the long-term build expected to be funded? A countywide sales tax measure headed for the November ballot would raise the rate from 7.75% to 8.25%, generate $360 million in its first year, and dedicate 22.5% to Tijuana River Valley sewage mitigation; Aguirre has said that revenue, if approved, could bond up to $1 billion in infrastructure San Diego Union-Tribune.
