The San Diego County Board of Supervisors unlocked approximately $6 million in reserves and is planning to spend a portion of that money on evaluating the first phase of a project to build a new treatment plant, separate from the existing South Bay plant, to capture and treat Tijuana River sewage flows.
On Sept. 1, the board established the Tijuana River Capture and Cleanup Initiative with three phases to build a new treatment plant near the U.S.-Mexico border, at a starting cost of $1.8 million to evaluate options including past proposals.
A county board letter about the initiative does not include a total price estimate nor where that money would come from or the treatment capacity for the plant and where it would be built. However, the letter says the first phase will consider a 2021 river diversion study by the U.S. Environmental Protection Agency (EPA).
“Phase 1 would build on that work and prepare the county to act by evaluating project pathway options, identifying the site and land rights, mapping permits, estimating costs, developing financing options,” the letter says. “… Phase 1 is expected to return to the board within 18 months with an analysis of top options for board consideration and selection.”
Under the board’s direction, the Ad Hoc Subcommittee on the Tijuana River Sewage crisis is dissolved, emerging as the Standing Committee on the Tijuana River pollution crisis, which the letter says gives permanent oversight on the initiative through every phase of delivery.
The board also agreed to fund the design, engineering, and environmental review for a proposed Saturn Boulevard box culvert project at a cost of $4 million, enabling the county to pursue state and federal construction funding.
The project’s total construction is estimated at $23 million and the county is currently working on an interim solution by 2027. A county feasibility study identified replacement of culverts beneath Saturn Boulevard with a larger box culvert for water to move more freely through the channel, reducing the turbulence that releases harmful gases into the air, says the board letter calling for the permanent solution.
According to the county, more than 200 billion gallons of untreated waters – carrying sewage, industrial chemicals, pesticides, heavy metals, and “forever chemicals” – have entered the United States through the Tijuana River since 2018, polluting the valley and ocean shoreline. Some of the contamination becomes aerosolized as hydrogen sulfide at a river hot spot near Saturn Boulevard, exceeding a state standard of 30 parts per billion (ppb) at 500 ppb.
Terra Lawson-Remer, the board chair, said Tijuana is projected to grow by 40% in the next 25 years.
“We need solutions that are forward looking so that our kids and our grandkids are not feeling the same crisis that we’ve been dealing with for a generation,” she added.
Lawson-Remer, who represents District 3 (including Coronado), and Chair Pro Tempore Paloma Aguirre, who represents District 1, submitted letters urging the board’s support on the projects.
The EPA study estimates a $63 million cost to divert 163 million gallons per day (MGD) of Tijuana River flows to an advanced primary treatment plant where that capacity’s treatment process is estimated to cost $640 million during a 40-year life cycle.
In late June, the board authorized a measure (“Protect San Diego County’s Health and Safety Act”) on the ballot, which if approved by voters in the Nov. 3 general election, would increase the sales tax by a half-cent in San Diego County for health and safety priorities, including the Tijuana River sewage crisis.
Soon after, Aguirre published the Tijuana River Sewage Crisis Funding Allocation Analysis which estimates up to $520 million annually from the measure for treatment infrastructure.
According to Aguirre, the Biden and Trump administrations have refrained from diverting and treating the river because it was too costly.
“There is the current Trump administration talking about the 100% solution, that is a 100% upgrade and fix to the International Wastewater Treatment Plant, which treats sewage from Mexico and treats zero flows coming through the river. … They’re talking about waiting for Mexico to fix it,” said Aguirre on Sept. 1.
‘We’re not going to slow down’
For decades, the crisis has caused environmental, economic, and public health hardships on Coronado and other South Bay communities in and surrounding the Tijuana River Valley.
Full expansion of the South Bay International Wastewater Treatment Plant, expanded to treat 35 MGD in 2025, is scheduled for December 2027, as agreed between the U.S. and Mexico. At a cost of $300 million, that federally funded project is designed to increase the existing facility’s wastewater treatment capacity to 50 MGD.
“We can no longer let our environment and public health depend on another government’s timeline,” said Vice Chair Monica Montgomery Steppe. “… I support the local capture and clean up along with the Saturn Boulevard project.”
Supervisor Jim Desmond agreed that constructing a new treatment plant to capture the untreated river flows would be a good use of the county’s reserves.
“I’ll be supportive, but hopefully we won’t have to build this plant and Mexico does it ahead of us,” said Desmond.
Desmond noted binational projects slated for completion in the next 18 months, as outlined in agreements between the Trump administration and Mexico.
“However we’ve seen a track record of that not happening,” said Desmond. “…We’ve got to be able to come up with pressure on Mexico, and be willing to enforce it to stop the flow of sewage into the United States.”
Supervisor Joel Anderson, who requested the board vote separately on the two items, expressed support for the hotspot fix, but called for regional support of the treatment plant. He also proposed water restrictions by the Otay Water District to Tijuana, describing it as “leverage.”
Anderson said he would rather spend $1.8 million buying water from the district so it is not sold to Tijuana.
“Force TJ’s hand because I don’t think they can survive if we cut off their water,” Anderson said “… That would really change the level of participation.”
Lawson-Remer said the county’s treatment initiative brings leadership to the issue and allows for options to build the kind of coalition Anderson suggested.
According to Lawson-Remer, a pre-construction analysis will produce three to five options for discussion with state and federal governments as well as area cities.
“I personally pledge to put the work in to try to make that happen,” said Lawson-Remer. “But I also pledge that we’re not going to slow down and we’re not going to stop if people don’t want to work on this, because it’s too important for our community.”
The treatment initiative passed in a 4-1 vote, with Anderson voting no. The board unanimously approved preparatory work on a permanent box culvert at Saturn Boulevard.
