From Paradise to Pollution: Imperial Beach's Ongoing Sewage Crisis

Imperial Beach, California, faces one of the nation's most severe environmental disasters, with 50 million gallons of untreated sewage, industrial chemicals, and trash flowing daily from Tijuana, Mexico, into southern San Diego County waters. The crisis has forced the closure of Imperial Beach's shoreline for more than 1,200 consecutive days due to public health concerns.

The cross-border pollution problem dates back at least a century but has worsened dramatically in recent years as Tijuana's population exploded to roughly 2.3 million people. Sewage treatment plants in both countries have fallen into disrepair, unable to handle the increased volume.

The Environmental Protection Agency now monitors this crisis as American officials work with Mexican authorities to address infrastructure failures on both sides of the border. What was once an idyllic beach community has transformed into an environmental disaster zone. The sea breeze now carries the stench of rotten eggs, forcing Mayor Paloma Aguirre to permanently seal the windows of her home.

The toxic air contains hydrogen sulfide at levels that can cause headaches, skin infections, neurological disorders, respiratory problems, and—in high concentrations—death, according to San Diego State University public health researcher Paula Stigler Granados. 

The health impacts extend far beyond unpleasant odors. More than 1,100 Navy recruits have contracted gastrointestinal illnesses after training in southern San Diego waters, the Office of the Naval Inspector General determined.

A Centers for Disease Control and Prevention survey of 189 households conducted in October 2024 found that nearly 70% of South Bay households reported that one or more family members had health symptoms from the sewage crisis like nausea, upset stomach, irritated throat, and shortness of breath.

Additionally, 80% believed their quality of life was negatively impacted, 67% believed their health had gotten worse since the problem rapidly worsened in recent years and 18% had sought medical care as a result of the sewage crisis.

Federal authorities are implementing multiple measures to address the crisis. EPA Administrator Lee Zeldin announced in April 2025 that his agency would fast-track expansion of the South Bay International Wastewater Treatment Plant, aiming to complete improvements within 100 days rather than the originally planned two years.

The U.S. International Boundary and Water Commission has secured $600 million to double treatment capacity to 50 million gallons per day, though the full expansion will take five years to complete. 

Imperial Beach officials have petitioned the EPA to designate the Tijuana River Valley as a Superfund site, which would unlock additional federal resources for cleanup efforts. However, the EPA rejected this request in January 2025, citing past data rather than conducting new site assessments. Mayor Aguirre has renewed calls for Superfund designation under President Donald Trump's administration, arguing that the crisis would have been resolved quickly if it affected more affluent communities. 

The long-term health implications for residents exposed to untreated sewage remain concerning. Medical experts warn prolonged exposure to sewage-contaminated water and airborne particles can lead to serious bacterial infections, including campylobacteriosis and E. coli, which can develop into life-threatening complications such as kidney failure. Parasitic diseases like cryptosporidiosis and giardiasis are also common risks associated with sewage exposure. Children, elderly individuals, pregnant women, and immunocompromised persons face the greatest health risks from waterborne pathogens. 

Research published in environmental health journals indicates untreated sewage elevates concentrations of nutrients, pathogens, endocrine disruptors, heavy metals, and pharmaceuticals in natural ecosystems. Studies have linked direct contact with contaminated water to elevated risks of asthma, gastrointestinal illnesses, and skin infections, particularly among children residing near sewage overflow sites. 

Public health officials recommend several protective measures for residents and tourists. San Diego County's Air Pollution Control District advises residents to stay indoors, close windows and doors, and run air purifiers during extreme odor events. People with chronic conditions such as asthma or chronic obstructive pulmonary disease should keep rescue medications readily available and seek medical care if experiencing persistent symptoms caused by strong odors. 

The county's Beach and Bay Water Quality Monitoring Program provides daily water testing results at sdbeachinfo.com, allowing the public to check current conditions before visiting beaches. San Diego County became the first coastal community to implement rapid digital droplet polymerase chain reaction testing, providing same-day water quality results rather than waiting 24 hours for traditional test results. When bacterial levels exceed state health standards, the county issues advisories, warnings, or closures to protect public health. 

Lifeguards working in contaminated areas now use protective equipment, including leak-proof dry suits, face shields, and decontamination showers after water contact. Volunteers from the Surfrider Foundation's Blue Water Task Force who monitor water quality wear protective gear and rinse off immediately after collecting samples. The organization recommends that recreational users avoid all water contact at Imperial Beach until infrastructure improvements are completed. 

The economic impact extends beyond Imperial Beach to nearby Coronado, where the historic Hotel del Coronado has seen reduced bookings due to intermittent beach closures. Mayor John Duncan expressed concern that the region's reputation as "the toilet of Mexico" could permanently damage tourism. Four San Diego County beaches adjacent to the Tijuana River made Heal the Bay's 2024 "Beach Bummer" list for worst water quality in California.