In a significant bilateral effort, the governments of Mexico and the United States signed a memorandum of understanding on Thursday, pledging to jointly fund and accelerate wastewater treatment initiatives within the Tijuana River basin.
The Tijuana River, which flows from Mexico into southern San Diego neighbourhoods, has long been a source of public health concern due to the ongoing discharge of untreated sewage.
Communities along its path have endured persistent health issues, which researchers attribute to toxic pollutants in the water.
A research team from the University of California San Diego recently highlighted that contaminants such as chemicals from tires, personal care items, and illicit drugs are not only present in the river but are also becoming airborne, worsening the health risks for tens of thousands of residents nearby.
At the signing ceremony held in Mexico City, U.S. Environmental Protection Agency Secretary Lee Zeldin and Mexico’s Secretary of the Environment and Natural Resources Alicia Bárcena laid out a joint roadmap for action through 2027 to tackle the worsening wastewater crisis.
“What we are doing, in reality, is trying to resolve once and for all the problem of wastewater from the Tijuana River,” Bárcena stated during the event.
Zeldin echoed her remarks, calling the agreement “a huge win for millions of Americans and Mexicans.” He credited the breakthrough to former President Trump’s focused attention on the issue and emphasized that the initiative would benefit both local communities and military training operations. “Addressing the water contamination crisis will ensure a safer environment for residents and Navy SEALS training on nearby beaches,” he said.
Former Commissioner of the International Boundary and Water Commission, Maria-Elena Giner, praised the development as “excellent news,” noting it strengthens commitments established under Minute 328.
That document outlines the shared responsibility between both countries to maintain and operate wastewater treatment infrastructure along the border.
The agreement introduces a new sense of urgency, setting the stage for previously delayed or unfunded projects to move forward.
It also calls for increased transparency, sustained diplomatic engagement, and clearly defined actions to ensure long-term progress.
A key focus of the pact is the renovation of the San Antonio de los Buenos treatment plant, located just southwest of Tijuana.
Bárcena announced during Mexico’s presidential daily press conference on Friday that she is working to finalize an arrangement for both countries to split the cost of the $67 million (1.2 billion pesos) upgrade.
With the ruling Morena party, led by Mexican President Claudia Sheinbaum, holding sway over the nation’s legislature, there’s optimism that funding allocations will be secured in the upcoming 2026 and 2027 budgets.
