Contaminated wastewater from Tijuana’s failing sewer system has drifted north to Coronado, one of San Diego County’s wealthiest beach communities, according to a Wall Street Journal report published this month. As much as 30 million gallons of sewage-tainted water may be flowing from the Tijuana area into U.S. coastal waters daily. The pollution, long confined to Imperial Beach near the border, now affects shoreline near the iconic Hotel del Coronado and U.S. Navy training areas. For anyone living or doing business along the Baja coast from Tijuana to Ensenada, the Tijuana sewage crisis carries consequences that extend well south of the border fence.
Tijuana’s Sewer System Has Been Failing for Over a Decade
The roots of this crisis stretch back years. Tijuana’s population has grown to roughly 2 million, but its wastewater infrastructure was largely designed for a much smaller city. CESPT, Tijuana’s municipal water and sewer utility, operates a network of aging pipes, pump stations, and treatment plants that regularly fail during heavy rains or mechanical breakdowns. When those systems go down, raw or partially treated sewage flows into the Tijuana River, which crosses the border into California’s Tijuana River Valley before emptying into the Pacific.
The problem accelerated after 2018, when a series of pipe collapses and pump station failures sent massive volumes of untreated wastewater across the border. In 2024, San Diego County officials declared a public health emergency related to cross-border sewage flows. Imperial Beach, the small coastal city closest to the border, has endured beach closures totaling hundreds of days per year since 2017.
On the Mexican side, environmental groups have documented sewage discharge into the ocean at Playas de Tijuana, where beachgoers sometimes encounter brown water and foul odors. Punta Bandera, the surf break and beach area south of Rosarito, has also been flagged for water quality problems tied to upstream sewage flows. CESPT has acknowledged equipment failures at the San Antonio de los Buenos wastewater treatment plant, which sits on the coast south of Tijuana and has operated well below its designed capacity.
Binational Repair Efforts Are Underway but Years From Completion
The U.S. Environmental Protection Agency and Mexican federal agencies, including CONAGUA (Mexico’s national water commission), have committed to a binational infrastructure plan. The centerpiece on the U.S. side is the expansion of the South Bay International Wastewater Treatment Plant in San Ysidro, which currently processes about 25 million gallons per day. The EPA’s proposed expansion would roughly double that capacity, but construction timelines extend into the late 2020s.
Congress allocated $300 million through the U.S.-Mexico-Canada Agreement (USMCA) implementation act specifically for border water infrastructure. The EPA has used portions of that funding for emergency repairs, including work on the canyon collectors that capture cross-border flows before they reach the Tijuana River estuary. Yet the agency has acknowledged that emergency measures alone cannot solve the underlying problem: Tijuana generates more wastewater than either country’s infrastructure can currently handle.
On the Mexican side, CONAGUA and CESPT have pursued repairs to key trunk lines and pump stations within Tijuana. The EPA has referenced Mexican projects involving river gates, collection pipes, and rehabilitation of wastewater lines in the Tijuana River channel. But Mexico’s federal budget for water infrastructure has faced repeated cuts, and CESPT has struggled with both funding shortfalls and staffing challenges. A full fix requires sustained investment on both sides of the border, and neither government has committed to a firm completion date.
Beach Closures and Headlines Hit Baja Tourism From Rosarito to Ensenada
The reputational cost to Baja’s coast is real and measurable. Visitors planning a weekend in Rosarito or a wine trip to the Valle de Guadalupe often scan headlines before booking. When U.S. media report “Tijuana sewage” and “beach closures” in the same sentence, the damage spreads far beyond Imperial Beach. Hotel operators in Rosarito have reported cancellations tied to water quality concerns, even when Rosarito’s own beaches are not under advisory.
Ensenada, roughly 80 miles south of the Tijuana River outfall, sits well outside the affected pollution zone. But the distinction is lost on many casual visitors who associate the entire Baja coast with a single set of headlines. Real estate agents marketing coastal properties from Playas de Tijuana to La Fonda have noted that buyer inquiries now routinely include questions about sewage.
For swimmers, surfers, and beachgoers on both sides of the border, the public health risk centers on pathogens carried in untreated wastewater. Environmental groups have warned of bacteria, viruses, and parasites that can cause gastrointestinal illness, skin infections, and respiratory problems. Risk increases after rainstorms, which overwhelm Tijuana’s sewer system and push larger volumes of contaminated water into the ocean.
Reliable water quality data for Baja beaches can be difficult to find in English. CESPT occasionally posts advisories in Spanish on its social media accounts. On the U.S. side, San Diego County’s “SD Beach Info” website (sdbeachinfo.com) provides daily water quality testing results for beaches from Coronado south to the border. Surfers and swimmers heading to Playas de Tijuana, Punta Bandera, or Rosarito should check for posted warning signs at beach access points and avoid the water for at least 72 hours after significant rainfall.
The EPA’s next public update on binational infrastructure progress is expected this summer. On the Mexican side, CESPT has indicated that repairs to the San Antonio de los Buenos plant are ongoing but has not provided a timeline for full operational capacity. The Wall Street Journal first reported the Coronado contamination findings earlier this month.