San Diego Congress members are calling on the U.S. State Department to press Mexico to address unprecedented levels of sewage pollution spilling over from Tijuana, causing unbearable rotten-egg odors for residents in the region.
In a letter Wednesday, officials asked the State Department to explain its steps to pressure the Mexican government or say why it has not done more to help stop thousands of tons of sediment and trash from crossing the border.
Reps. Juan Vargas, Sara Jacobs, Scott Peters and Mike Levin and U.S. Sens. Laphonza Butler and Alex Padilla addressed the joint correspondence to Secretary of State Antony Blinken, Assistant Secretary of State for Western Hemisphere Affairs Brian A. Nichols and U.S. Ambassador to Mexico Ken Salazar.
Mexico and the U.S. have boundary and water treaties, including a treaty known as Minute 328 that outlines a comprehensive plan to fix the cross-border sewage crisis via numerous infrastructure projects on both sides of the border. The U.S. International Boundary and Water Commission (USIBWC), which is responsible for the San Ysidro-based South Bay International Wastewater Treatment Plant, operates under the foreign policy guidance of the State Department. That means the USIBWC’s budget is submitted through that department and appropriated by Congress.
Specifically, Congress members inquired about the following:
• What is the State Department doing to convey to Mexican officials “the harm that the sediment and the ongoing smells are having on residents of San Diego?” Does it need support from Congress to do so?
• Has the department considered giving Mexico an official diplomatic reprimand, known as a démarche, over the excess volumes of dry-weather sewage flows? And if not, what factors have led the agency to conclude the move is not appropriate?
• What is the department doing to ensure SEDENA, the Mexican defense ministry, has a plan to mitigate sediment?
“Because this is a dire situation, we look forward to receiving a timely response to the questions listed above,” officials wrote, issuing a deadline of Sept. 6.
On Thursday, a State Department spokesperson said via email that the department does not comment on congressional correspondence but is “coordinating closely with the Government of Mexico on projects on the Mexican side of the border that will reduce transboundary flows.”
U.S. Deputy Secretary of State Richard R. Verma backed up that statement after taking a tour Thursday of the South Bay plant, where he got a first-hand account of the lingering sewage odors residents have been complaining about.
“We are in regular contact with the (Mexican) government on this issue. We exchange a set of diplomatic notes,” he said when asked at a news conference if the executive department had considered issuing a démarche.
Verma’s visit, accompanied by other officials from state and federal agencies, marked the first high-level visit from an executive department of the federal government to the facility in recent history, following a 2023 request from the San Diego congressional delegation to have Secretary of State Blinken witness firsthand the dire need to fund repairs and expansion of the South Bay plant.
Verma said efforts continue to bring in more money for the USIBWC to invest in the facility, as well as other projects it’s juggling across the border.
Wednesday’s letter comes as the USIBWC has struggled to comply with federal water-quality standards because the South Bay plant repeatedly fails to treat wastewater. The agency recently approved a contract to begin work to repair and expand the plant. But it will take several years before all is completed. Officials say unprecedented amounts of sedimentation from Mexico are compromising repair efforts.
The federal agency has recorded peak levels of partially treated wastewater and sediment. According to its data, wastewater flows reached a record high of 44 billion gallons last year — the highest amount recorded in the last quarter-century. So far this year, its figures showed, the federal agency has hauled 8,294 tons of sediment and trash from its treatment plant, nearly 10 times more than the previous year.
Commissioner Maria-Elena Giner, who heads the USIBWC, said Mexico has not explained where the sediment comes from and why it has not implemented control measures. The federal agency believes some of the sedimentation buildup is due to an ongoing highway construction project in Tijuana.
Rainstorms in recent years have brought staggering amounts of pollution over the border into the southern San Diego area, flooding some South Bay roads where people have had to be rescued, extending beach closures, and bringing sedimentation and trash to the Tijuana River Valley.
But flows have not stopped during dry weather seasons. Much of that pollution clogs treatment infrastructure that is already in poor shape and underfunded.
“Residents of Imperial Beach and South San Diego County have shared that the sewage odors linger all day and night, frequently causing them to wake throughout the night from the smell,” Congress members said in their letter. “These increased flows affect the lives and livelihoods of the residents living near the Tijuana River and endanger the health and safety of our communities.”