U.S., Mexico sign new agreement on Tijuana River sewage crisis

The United States and Mexico signed a new agreement Monday aimed at addressing the decades-long Tijuana River sewage crisis, but U.S. Environmental Protection Agency officials who announced the accord were not clear about penalties for Mexico if their side of the agreement was not held up, nor did it address a critical pollution hotspot on U.S. soil.

Minute 333 outlines infrastructure projects, enhanced monitoring and planning for operation and maintenance of wastewater systems to account for future population growth in Tijuana — a component missing from previous agreements. The U.S.-Mexico accord does not obligate any additional taxpayer funding, including for Mexican-side projects.

“This strategic legal contract between the governments of Mexico and the United States contains measurable progress of necessary infrastructure projects — on both sides of the border — moving us closer toward a final 100% Solution for our region’s long-standing Transboundary Sewage Crisis,” Imperial Beach Mayor Mitch McKay said in a statement.

The agreement follows a memorandum of understanding signed in July by EPA Administrator Lee Zeldin and Mexico’s Secretary of the Environment and Natural Resources Alicia Bárcena Ibarra.

“The San Diego congressional delegation has worked to fix the very serious health danger of toxic wastewater flowing across the U.S.-Mexico border for years and we have secured hundreds of millions of dollars to fix and expand the aging plant,” Representative Scott Peters said in a statement. “But Congress cannot do this alone.”

Key Provisions

Mexico will construct a sediment basin in Matadero Canyon, known as Smuggler’s Gulch, near the international boundary before the 2026-27 rainy season. The basin is expected to significantly reduce sediment entering the United States.

The State of Baja California will construct the Tecolote-La Gloria Wastewater Treatment Plant with a capacity of 3 million gallons per day by December 2028 to address untreated wastewater being discharged into the Pacific Ocean.

A binational working group will assess the feasibility of constructing an ocean outfall for the San Antonio de los Buenos Wastewater Treatment Plant and evaluate expanding the plant’s capacity from 18.26 million gallons per day to 43.37 million gallons per day. The working group has three months to make recommendations to the EPA.

The agreement also calls for developing a Tijuana water infrastructure master plan within six months and creating an operations and maintenance account at the North American Development Bank to set aside funds for future maintenance costs.

Funding Questions

During a press briefing Monday, EPA Deputy Administrator David Fotouhi acknowledged that funding remains central to addressing the crisis.

When asked about potential cost increases due to reduced construction timelines, Fotouhi said the EPA has been “very focused on making sure that we are being good stewards of taxpayer dollars.”

The EPA reported in October that a 100-day review eliminated nine additional months from construction timelines. Combined with earlier reductions, approximately 12 years of construction time has been cut across all projects since the July memorandum of understanding, according to the EPA.

Thomas Corlett, senior advisor to EPA Administrator Zeldin, said during the briefing that most projects with accelerated timelines are on Mexico’s side of the border and Mexico is responsible for 100% of their funding.

The EPA did not respond to follow-up questions about higher costs associated with reduced construction timelines or consequences if Mexico fails to meet its obligations.

The Good and the Bad

Ramon Chairez, director of education and environmental advocacy at Un Mar de Colores and a member of the Tijuana River Coalition, said the agreement has encouraging elements.

“I think when you look at how the federal government has worked with Mexico … to really outline where some of the infrastructure gaps are in Mexico and what they are, I think that’s a step in the right direction,” Chairez said.

He pointed to the acknowledgment of the San Antonio de los Buenos plant’s capacity issues as particularly significant. The plant was recently repaired but has a capacity of 18 million gallons per day while an equal or greater amount bypasses the facility and flows untreated into the ocean.

Chairez expressed concern that of the 13 resolutions in the agreement, only two focus on construction projects while the rest primarily concern studies and planning.

“What’s outlined are just a long list of studies, whether they’re engineering or technical or financial feasibility studies,” he said. “So it kind of puts us all in a waiting game. And that’s kind of where we’ve all been for a while, for years.”

Saturn Boulevard Hotspot Omission

Chairez’s strongest criticism centered on the complete absence of any mention of the Saturn Boulevard hotspot, a location on U.S. territory where toxic gases like hydrogen sulfide are aerosolized during high flows and carried by the wind into surrounding communities.

“We don’t have to ask permission from Mexico to do anything there,” Chairez said. “We just have to go and do it.”

The foam produced by the aerosolization is visible from space via satellite imagery, and eleven schools sit within 1.5 miles of the hot spot, exposing thousands of children to toxic pollutants on a regular basis.

He called addressing the hotspot “low hanging fruit” and questioned why the county, Navy, IBWC and city of San Diego cannot coordinate to resolve the issue with the same urgency being applied to other aspects of the crisis.

“Whenever there’s high flows, there’s going to be toxic gases flowing from there,” Chairez said.

The EPA did not respond to follow-up questions about the hotspot or why it wasn’t mentioned in the agreement.