Tijuana’s main wastewater pipeline collapsed late Friday night, marking the second break on the same line this month. The failure on the Parallel Gravity Line, which carries sewage through central Tijuana to a treatment plant near the U.S.-Mexico border, has forced Mexican authorities to shut down several pumps along the border while repair crews work to fix the damage.
The U.S. International Boundary and Water Commission (USIBWC) confirmed the collapse on May 30 after being notified by its Mexican counterpart, the Comisión Internacional de Límites y Aguas (CILA). The exact cause of the collapse remains unknown.
Stronger Odors and Increased Flows
Residents on both sides of the border can expect stronger odors and increased wastewater flows in the Tijuana River Channel while pumps remain offline. The USIBWC said it is monitoring flows, sediment, and trash in canyon collectors and coordinating with Mexican water authorities to bring all suspended pumps back online as quickly as possible.
The South Bay International Wastewater Treatment Plant (SBIWTP) in San Diego continues to operate normally, and no transboundary sewage flows have been reported so far. Beach closures, however, remain a possibility if conditions worsen.
Second Break in May
This is the second failure on the Parallel Gravity Line in less than three weeks. Emergency repairs on the same pipeline began on May 14, and officials from both countries said at the time that the work prevented additional sewage from entering U.S. waters. Those repairs took roughly 24 hours, during which Mexico diverted sewage flow to the SBIWTP.
The aging pipeline has a long history of leaks and emergency interventions. In January 2026, a major sewage pipe collapse in eastern Tijuana sent an estimated 11 million additional gallons of untreated wastewater per day into San Diego through the Tijuana River, according to the USIBWC. Residents near the Tijuana River Valley reported intense odors that penetrated homes for days.
Ongoing Infrastructure Concerns
The pattern of repeated failures on this critical line is a growing concern for coastal communities in both Baja California and San Diego County. Over the past five years, more than 100 billion gallons of untreated sewage and industrial waste have spilled into the Pacific Ocean from the Tijuana River, according to previous studies cited by NBC News. Environmental groups have called on Mexico to accelerate rehabilitation of decades-old sewage infrastructure.
For Tijuana and Playas de Tijuana residents, as well as beachgoers along the northern Baja coast, the immediate concern is air quality and potential water contamination during the repair period. The USIBWC has not provided a timeline for when pumps will return to full operation.
This story was first reported by NBC 7 San Diego and ABC 10 News San Diego.