Untreated Wastewater From Tijuana Continues to Pollute Southern California Beaches

Millions of gallons of sewage-tainted water from Mexico continue to reach some of Southern California’s most popular beaches, resulting in repeated closures. The contamination flows from the Tijuana River, which carries untreated wastewater across the border into U.S. waters.

Ocean currents then push the pollution northward along the coast. As much as 30 million gallons of sewage-tainted water can enter the Pacific Ocean daily from Tijuana. In Coronado, county officials have urged visitors to avoid the water as polluted runoff reaches the shoreline.

Warning signs have been posted to alert beachgoers that exposure could lead to illness. The pollution has affected waters near the historic Hotel del Coronado. Health authorities state that contact with the contaminated water can cause gastrointestinal illness.

Airborne toxins linked to the sewage, including hydrogen sulfide, may trigger headaches, eye irritation, respiratory issues and other health effects. Children in nearby communities have reported worsening asthma symptoms, skin rashes and additional issues associated with the pollution.

The situation has affected local tourism and disrupted military activities, including Navy SEAL training at the Naval Amphibious Base Coronado.

Mexico signed an agreement in July 2025 that outlines specific steps and a revised timetable to reduce the flow of untreated wastewater. The pact includes reduced timelines for Mexico-side projects at no additional cost to U.S. taxpayers. Projects are scheduled for completion in 2026, 2027 and one in 2028.