Tijuana River Valley

Understanding the Tijuana River Sewage Crisis

For more than half a century, untreated sewage, trash, and industrial waste have flowed through the Tijuana River into San Diego County. This persistent cross-border pollution has contaminated our waterways, fouled our coastline, and forced beach closures stretching from Imperial Beach to Coronado. The root causes include aging infrastructure, overwhelming urban growth, and underinvestment in wastewater treatment on both sides of the border.

The Crisis Today

The Tijuana River sewage crisis is more than an environmental disaster—it’s a public health emergency. When toxic waste and bacteria-laden water cross our border, families lose access to safe beaches, lifeguards and Navy SEALs are exposed to hazardous contaminants, and local businesses that rely on clean water suffer. Studies by the Center for Disease Control and academic institutions show that these flows contain high levels of pathogens, heavy metals, and chemicals that pose serious health risks, and families that live in the South Bay are falling in.

A newly published, peer-reviewed study in Science, led by researchers from UC San Diego, UC Riverside, SDSU, and the National Center for Atmospheric Research, reveals an alarming new dimension: polluted waters from the Tijuana River are also degrading air quality. The team detected hydrogen sulfide—commonly known as “sewer gas”—at concentrations up to 4,500 parts per billion (ppb) in the Nestor neighborhood, far exceeding safe exposure levels.

Beyond hydrogen sulfide, researchers identified hundreds of other airborne toxins—including chemicals from industrial waste, personal care products, and even drug residues—suggesting widespread exposure across South Bay communities. This is the first study to establish a direct link between waterborne sewage pollution and airborne health hazards in our region.

Research, Accountability, and Community Validation

Years of studies have mapped pollution sources, measured impacts, and outlined specific infrastructure fixes. Federal and state agencies have completed engineering assessments and environmental reviews identifying the projects needed to stop raw sewage before it reaches U.S. waters. The science is clear: this crisis is solvable, but only with sustained investment, oversight, and urgency.

For years, residents in neighborhoods like Nestor have reported foul odors, headaches, and respiratory problems—yet lacked definitive proof of the cause. This new study validates their concerns, providing hard data that repeated exposure to sewer gases at these levels can trigger nausea, irritation, and even long-term health effects.

How Supervisor Aguirre is leading this fight

1. Eliminate Toxic Hot Spots – Supervisor Aguirre wants to target and clean up the most dangerous areas where sewage and sewer gases are most concentrated.
   
   
2. Protect Kids and Schools – Provide air purifiers for schools and homes to keep children safe from toxic exposures.
   
   
3. Comprehensive Health Study – Partner with medical and academic institutions to fully understand the long-term health impacts on South Bay residents.
   
   
4. Economic Impact Data – Gather and share data on the costs of pollution—from closed beaches to lost business—to strengthen the push for federal resources.
   
   
5. Sewage Crisis Commissioner – Create a dedicated federal role to coordinate binational efforts, cut through red tape, and keep the response on track.

Ready to Act

Supervisor Aguirre remains steadfast: protecting public health, restoring environmental quality, and securing a safe future for South Bay residents. The new research provides compelling urgency, but real progress requires continued political will, binational collaboration, and investment.