Why it keeps happening

The beach doesn't close because of one broken pipe. It closes because of problems stacked on top of each other, and the deepest ones are the hardest to fix. This page works back from the equipment to the causes underneath.

A city that outgrew its system

Tijuana has grown to a metro area of more than two million people (about 1.9 million in the city itself, per the 2020 census) and its sewers and treatment plants haven't kept pace. Many neighborhoods, especially informal settlements on steep canyon slopes, were built without sewer connections or regular trash service. The coastal treatment plant at Punta Bandera receives about twice what it can treat.

Mexico has committed to a new 3 MGD plant, Tecolote–La Gloria, by December 2028, and a U.S.–Mexico working group created under an agreement called Minute 333 is studying how to plan for future growth. Much of that work is still at the study stage.

Old pipes and too little upkeep

Much of Tijuana's sewer network is decades old. A March 2026 report found that about 75% of Tijuana's sewer network and half its pump stations need urgent repair. When pipes aren't inspected, cleaned, and relined on schedule, they run until they break. The main line carrying sewage to the coast collapsed twice in May 2026. Pump stations were shut down for repairs, flows surged in the river channel, and the U.S. treatment plant absorbed most of it by running above 40 million gallons a day.

Money for construction has come more easily than money for maintenance. A 2021 EPA assessment noted that rising electricity costs and high operation and maintenance costs strain the Tijuana utility's limited budget. Minute 333 proposes a dedicated maintenance account at the North American Development Bank, with recommendations due by December 2026. Until that exists, new equipment risks the same fate as the old.

Industrial waste

Factories in Tijuana, most of them U.S.-owned export assembly plants, discharge into the same sewers as homes. Enforcement of the rules on industrial waste appears weak: a September 2026 San Diego Coastkeeper report found a steady stream of industrial chemicals, heavy metals and pesticides in the river, and standard biological treatment cannot remove some of them. Researchers have also found that large factories often outsource their dirtiest work to small, unregulated shops, whose scrap is dumped into canyons along with household trash.

Trash that breaks the equipment

More than 1,000 illegal dumpsites in Tijuana's canyons feed trash into the river and the border canyons. Irregular or pay-per-pickup trash collection in some neighborhoods drives the dumping. That trash clogs pumps, collectors, and culverts on both sides of the border, and it wrecked at least one technology trial. See Technology trials.

Storms bigger than any system

Even a well-maintained system would struggle with the rainy season. Storm flows averaging about 109 million gallons a day of sewage-contaminated water (EPA average, 2015–2019) overwhelm the river diversion, which shuts off above about 23 MGD. Nothing built or funded today is sized for that. San Diego County is designing a U.S.-side diversion and treatment system, but construction depends on a November 2026 ballot measure.

Agreements that depend on money

The Tijuana River watershed is about three-quarters in Mexico. The U.S. can't order repairs there; it can only negotiate, share costs, and tie its funding to Mexico meeting milestones. The two countries have signed a series of agreements through the International Boundary and Water Commission, most recently a 2025 memorandum of understanding and Minute 333 in December 2025. Minute 333 doesn't commit any new U.S. funding, and its actions depend on money being found.

That's why progress tends to come in bursts: a spill makes headlines, money is found, a project moves forward, and then the next gap appears somewhere else in the system.

What this means for fixes

The projects underway mostly address capacity at the border and specific failing pipes and pumps. The root causes on this page, from maintenance funding and industrial waste to trash collection and storm flows, mostly still lack funded solutions. The Problems to solve view on the map shows each one and where it stands.