Q&A: Understanding the Tijuana Sewage Crisis

For decades, residents of the South Bay have lived with a devastating reality: millions of gallons of untreated sewage from Mexico impacting their communities.

The scope of this crisis is staggering. While Tijuana’s population has surged and its borders sprawled, it has failed to build sufficient sewage infrastructure while existing infrastructure has crumbled. The result? A daily deluge of raw sewage from Mexico that flows directly into the Tijuana River and the Pacific Ocean.

The crisis is a direct result of Mexico’s failing and insufficient sewage infrastructure. Tijuana's population has doubled since 1997, but critical sewage infrastructure investments never materialized. While the United States federal government opened the South Bay plant in 1997 to handle cross-border flows of domestic-grade wastewater (i.e. not industrial effluent), Mexico failed to expand or maintain its own treatment capacity to match Tijuana’s explosive growth.

Four main causes are behind the daily flow of raw sewage from Mexico:

• Broken infrastructure: Old, crumbling pipes and systems in Tijuana regularly break, releasing raw sewage.
• Failed treatment plants: Mexico’s main treatment plant, San Antonio de los Buenos, has been offline for long periods, dumping untreated sewage directly into the ocean.
• Unconnected neighborhoods: Entire neighborhoods in Tijuana discharge their waste directly into waterways because they are not connected to any sewage system.
• Construction debris: A massive highway project in Tijuana has filled drainage channels with dirt and debris, which flow into the U.S. treatment plant and destroys equipment.

The numbers are staggering:

• Tijuana is estimated to generate around 100 million gallons of sewage per day, including wastewater and industrial effluent.
• The South Bay treatment plant, operated by Veolia, was designed to handle 25 million gallons per day and was recently upgraded to handle 35 million gallons per day. The plant can only treat what Mexico sends through a dedicated collection system.
• This means the overwhelming majority of Tijuana’s sewage never even reaches the plant. It flows directly from Mexico into the Tijuana River and the Pacific Ocean.

The Tijuana sewage crisis affects people on both sides of the border. Residents of Tijuana and its area endure untreated sewage contaminating their neighborhoods because of failing infrastructure in Mexico. While the crisis has gained a lot of media attention in the US, many Tijuana residents deal firsthandedly with consequences of raw sewage flowing from Mexican infrastructure in disrepair.

The solution for this cross-border issue is close cooperation between Governments and significant investment in Mexican wastewater infrastructure.

Veolia is a contractor hired by the U.S. government to operate and maintain the South Bay International Wastewater Treatment Plant.

Our dedicated team works 24/7 under extremely difficult conditions to treat the fraction of Tijuana’s wastewater that Mexico sends. Every gallon we treat is one less gallon polluting San Diego’s environment. We operate the plant, but we do not have any control or authority over Mexico’s infrastructure, policies, or the massive volume of sewage it generates and discharges into the Tijuana River and Pacific Ocean.

The South Bay International Wastewater Treatment Plant (SBIWTP) is a U.S. federal facility built on the U.S. side of the border to address and treat some of the cross-border sewage flows coming from Mexico. Veolia operates this plant as a contractor for the U.S. government.

Its primary job is to treat a fraction of wastewater sent by Mexico through a dedicated system called the “international collector”. Thanks to its most recent upgrade in 2025, the plant can process up to 35 million gallons of wastewater every single day. The vast majority of Tijuana’s sewage does not reach the plant and is discharged by Mexico in the Tijuana River or the Pacific Ocean.

The plant’s operation is often disrupted by a flow of rocks, mud, and debris from Mexico (much of it from construction sites) that can destroy critical equipment and harm the plant’s operational performance. Despite these challenges, the SBIWTP functions as a critical line of defense, treating every gallon of wastewater it possibly can to protect San Diego’s communities and environment.

The plant operated by Veolia treats only a small fraction of Tijuana’s wastewater sent across by Mexico.

1. Most Sewage Does Not Reach the Plant: The vast majority of Tijuana’s sewage flows directly into the river and ocean, never entering the plant Veolia operates. We can’t treat sewage that never gets to us.
2. Excessive Volume: The amount of sewage that Mexico does send often exceeds the plant's maximum capacity.
3. Damaging Contents: The wastewater that does arrive is often mixed with industrial effluent, rocks, mud, trash and construction debris from Mexico that clogs systems and destroys critical equipment.

The lawsuits targeting Veolia are misguided and distract from the real problem. Lawyers are targeting Veolia because they see our company as a “deep pocket” and a convenient corporate scapegoat. Veolia employs 12,000 people in the United States, operating in 40 states and serving 20 million Americans and their communities. Veolia pays millions of dollars in taxes in the U.S.

Mexico's government and infrastructure operators are much harder to sue, even though they're the actual source of the pollution. Lawyers choose what they think is a quick and easy way to maximize their fees, regardless of the truth. In reality, these lawsuits create false hope for residents and provide political cover for Mexican authorities, diverting attention from their responsibility to fix their broken infrastructure.

Unscrupulous lawyers claim that suing the South Bay plant’s operator and the Federal Government will help resolve the crisis. This is untrue and misleading. Lawsuits target the wrong parties and drain time and resources away from fixing the problem. Well before lawyers appeared, Veolia had been working very hard to keep the plant running and help fix the crisis, although most of the sewage never reaches the plant. Suing Veolia is in nobody’s interest, except a few lawyers looking to make a quick dollar. The real solutions lie in raising awareness for U.S. and Mexican Governments to respond to the crisis.

Thankfully, real progress is finally being made thanks to strong leadership from the U.S. government.

• A historic agreement: In July 2025, the U.S. and Mexico signed a landmark agreement to “permanently and urgently end” the crisis. For the first time in years, this includes significant funding from Mexico and an accelerated timeline for new projects.
• Massive U.S. investment: The U.S. Congress has fully funded a $600 million project to expand and upgrade the South Bay plant, which will double its treatment capacity.
• EPA demands accountability: In April 2025, EPA Administrator Lee Zeldin visited San Diego and demanded “100% solutions” from Mexico, presenting a clear action plan to fix the problem at its source.

Yes. The combination of U.S. investment, strong federal leadership demanding accountability, and a new binational agreement marks a hopeful new chapter. The solutions exist, the funding is secured, and there is an unprecedented will to finally solve this crisis. Veolia has worked very hard to upgrade the plant’s treatment capacity to 35 million gallons per day. The key now is holding Mexico accountable for its commitments and completing the critical infrastructure projects on both sides of the border.