Tijuana pipeline failure dumps raw sewage into California—officials sound alarm

San Diego, California – Millions of gallons of raw sewage spilled from a construction site in Tijuana and flowed into San Diego County early Sunday, exacerbating existing pollution issues in the Tijuana River Valley.

The spill occurred after several days of rain, which had already increased the flow of polluted water in the region. According to the International Boundary and Water Commission (IBWC), the spill resulted from unforeseen construction issues during the replacement of Tijuana’s International Collector, a major sewage pipeline.

“Every time it rains, we have insane amounts of volume and flow of the river,” said Imperial Beach Mayor Paloma Aguirre. “We can’t take more of this.”

The IBWC confirmed that multiple construction problems, including difficulties installing inflatable plugs and unexpected wastewater flows from previously unknown pipes, led to the release of wastewater mixed with rainwater into the Tijuana River and Stewart’s Drain. An estimated three million gallons, exceeding the International Collector’s capacity, were released.

This flow caused debris to block the South Bay International Wastewater Treatment Plant’s (SBIWTP) Junction Box #1, temporarily disrupting the plant’s operation. The IBWC, along with the EPA and State Department, engaged with Mexican officials to investigate the cause of the spill.

“I have made it very clear to Mexico the importance of avoiding future transboundary flows to the greatest extent possible during this very complicated construction project,” said Dr. Maria-Elena Giner, Commissioner of the U.S. Section of the IBWC.

U.S. Rep. Scott Peters highlighted concerns that a proposed Congressional budget could slash the IBWC’s budget in half, potentially impacting future upkeep of the wastewater treatment facilities. While repairs to the SBIWTP are expected to continue, ongoing maintenance could be affected.

The incident drew attention from EPA Administrator Lee Zeldin, who called on Mexico to honor its commitments to control pollution. Mexican officials have committed to daily meetings with U.S. representatives to address the ongoing construction and potential problems.

The new International Collector, designed to carry up to 60 million gallons of untreated sewage daily to the SBIWTP, is intended to improve sewage infrastructure and reduce transboundary flows, but has faced construction delays.