(Image Credit: IMAGN) A sign along the Arroyo Simi in Moorpark warns of possible sewage contamination on Thursday, May 4, 2023. County officials recently detected a sewer line break that has sent millions of gallons of raw sewage into the channel.
San Diego, California – In a long-overdue step toward resolving one of the most persistent environmental and public health disasters along the U.S.–Mexico border, officials from the United States and Mexico signed a sweeping memorandum of understanding Thursday aimed at stopping the daily flow of untreated sewage from Tijuana into San Diego County.
Speaking from Mexico City, Environmental Protection Agency Administrator Lee Zeldin emphasized urgency above all else. “If any speed changes, that speed will have to be a speed to go faster,” he said during an online briefing. Zeldin, appointed by former President Donald Trump, has made the South Bay sewage crisis a personal priority since touring the Tijuana River Valley in April. “I smelled for myself that foul smell so many residents have complained about,” he said.
The new agreement lays out a binational roadmap to invest in, accelerate, and coordinate the long-stalled repairs and expansions to critical wastewater infrastructure in Tijuana. Among its key elements: Mexico has committed to spend at least $93 million to fulfill its obligations under previous accords, including Minute 328 of the International Boundary and Water Commission. It also outlines specific engineering and maintenance projects scheduled through 2027, with the goal of stemming the toxic outflow that has fouled San Diego’s beaches and sickened thousands.
On the U.S. side, the EPA pledged to expand capacity at the South Bay International Wastewater Treatment Plant from 25 to 50 million gallons per day by 2027, with an interim target of 35 million gallons by next August. The United States will also release additional funding from its Border Water Infrastructure Program to support pipe rehabilitation and other upgrades.
The memorandum goes beyond immediate fixes. It lays the groundwork for deeper binational cooperation, including real-time water quality monitoring, a jointly developed master plan for future water infrastructure, and mechanisms to ensure that funding for long-term maintenance is secured and managed. Officials plan to finalize a new Minute by the end of the year to formalize these efforts.
San Diego County Supervisor Paloma Aguirre, who has been outspoken on the issue since her time as mayor of Imperial Beach, welcomed the agreement but stressed the need for local action. “We are no longer going to talk about the problem—we are going to solve it,” she said, pledging that the county would expand illness tracking, issue new pollution warnings, and monitor for airborne contaminants within the next 30 days.
Some beaches in South County have now been closed for over 1,300 consecutive days, a symbol of the decades-long political inertia surrounding the crisis. That inaction may finally be giving way. “This is something that requires total follow-through,” said Zeldin. “The United States will hold Mexico’s feet to the fire.”
Local leaders echoed that sentiment. In a joint statement, San Diego Mayor Todd Gloria and County Supervisor Jim Desmond called the deal “a major step forward” and praised the federal government for treating the crisis with the seriousness it deserves.
Still, the work is only beginning. The timeline laid out in the agreement stretches through 2027, and past promises have gone unfulfilled. But this time, both governments say, accountability and urgency are non-negotiable.
