An emergency repair job on a leaking Tijuana wastewater pipeline kicked off yesterday, and South Bay residents are already catching the fallout in their noses. San Diego officials are warning that stronger sewage odors and potential beach closures are on the table while crews tackle the fix, a project expected to run at least 24 hours and take two Mexican pump stations offline as flows are rerouted. Neighbors in Imperial Beach, Nestor and the Tijuana River Valley have reported rotten-egg smells and irritation to eyes or throats, while county and federal teams say they have equipment staged at Smuggler's Gulch to limit any polluted water from crossing into U.S. territory.
USIBWC: Emergency Repairs To The Parallel Gravity Line
In yesterday's press release, the U.S. International Boundary and Water Commission said crews began overnight emergency work to repair a leak on the Parallel Gravity Line, a major conduit that carries wastewater in Tijuana. The agency warned that people in nearby communities could notice more wastewater in the system and stronger odors while the line is being fixed. Staff and equipment are already in place at Smuggler's Gulch, and the commission repeated its stance that "transboundary flows are unacceptable and the United States expects Mexico to take all necessary actions to stop any flows."
Pumps, Plant And Why The Smell Spikes
The repair work affects PBCILA and PB1, lift and pump stations that move dry-weather flows from Tijuana across the border. Officials say both facilities will be taken offline during the operation, sending more influent to the South Bay treatment plant and putting extra strain on a system that has faltered before. As KPBS reported, PB1 has failed in recent months, and earlier pump outages sent tens of thousands of gallons of sewage into the Tijuana River, fueling the region's persistent odor problems and repeat beach closures.
Air Monitoring And Short-Term Relief
County and air-district officials are closely watching hydrogen sulfide levels, the rotten-egg gas released as sewage breaks down. The San Diego County Air Pollution Control District runs an active H₂S monitoring program and an Air Improvement Relief Effort (AIRE) that supplies free air purifiers to households hit hardest by the stink. The district posts hydrogen sulfide advisories and information on how to report problems online, and regional agencies are trying to secure short-term relief even as longer-term infrastructure projects move forward. Both the San Diego County Air Pollution Control District and the San Diego Water Board post details on monitoring, advisories and available assistance.
What Residents Are Urged To Do
Local news outlets sounded the alarm early Friday, and officials are keeping their advice simple: stay out of the river, shut your windows when the smell gets intense and call a doctor if irritation or other symptoms do not let up. CBS8 reported the public notice, and the U.S. International Boundary and Water Commission again stressed that it expects Mexico to take every possible step to stop any cross-border flows while repairs are underway.
Big Picture: Upgrades Still In Progress
This emergency fix is unfolding in the middle of a broader, binational push to overhaul Tijuana's aging collectors and pump stations. That work includes planned rehabilitation of the same Parallel Gravity Line, now receiving emergency attention, as well as system expansions intended to increase treatment capacity and reduce future spills. Regulators say the long-term upgrades are designed to prevent repeat outages and ease the chronic odors and beach closures that have hammered South Bay communities for years. The San Diego Water Board maintains a public timeline of planned improvements and funding tied to the binational agreement.
