Untreated sewage from Tijuana River closes Southern California beaches daily.

Southern California's most popular beaches are closing repeatedly as sewage continues to pollute coastal waters. In Coronado, a community near San Diego, county officials have issued advisories telling visitors to stay out of the water. Warning signs posted along the shore indicate that contact with the polluted runoff entering the Pacific Ocean can cause illness.

The primary source of this contamination is the Tijuana River, which transports untreated wastewater from Mexico into U.S. waters. Ocean currents then carry the pollution northward along the coastline, spreading the hazard across multiple locations.

The scale of the problem is substantial. As much as 30 million gallons of sewage-contaminated water can flow into the Pacific Ocean daily from the river, according to The Wall Street Journal. This volume is polluting beaches throughout the Southern California coast. The issue is so severe that even high-end beachfront properties have been affected. Waters near the historic Hotel del Coronado have faced closures due to unsafe conditions.

Health risks associated with the pollution are significant. Sewage contamination has been linked to respiratory problems and other illnesses in nearby communities. Hydrogen sulfide, a gas commonly found in sewage, can irritate the eyes and respiratory system. In higher concentrations, it may cause serious health effects, according to the Centers for Disease Control and Prevention.

Exposure to contaminated water can lead to gastrointestinal illness, while airborne toxins have been linked to headaches and breathing difficulties. Medical professionals and community advocates report that children have been especially impacted. Some residents have observed increased asthma symptoms, skin rashes, and other health issues tied to the pollution.

Residents have also expressed concern over persistent odors along the coastline. One individual noted on Reddit that a really unpleasant sewage odor drifts into their apartment, stating it has been happening for months with no improvement. Another user described the situation as nasty and remarked that it has been going on too long.

The sewage issue has drawn attention at the federal level, with officials warning of broader impacts on public health and national security. President Donald Trump has called on Mexico to address the flow of untreated wastewater entering the United States, describing it as a threat to nearby communities.

Local leaders state that the contamination has negatively affected tourism and military operations. This includes disruptions to Navy SEAL training at Naval Amphibious Base Coronado. The situation highlights a critical environmental and public health challenge that requires immediate attention and cooperation between nations.