Tijuana River Sewage Reaches 22 Miles up Coast
Researchers from UC Riverside and Scripps Institution of Oceanography tracked sewage-tainted water flowing north along San Diego County's shoreline.
Updated on Nov. 7, 2026 in Geography
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A study by researchers from the University of California, Riverside and UC San Diego's Scripps Institution of Oceanography found that polluted water from the Tijuana River travels roughly 22 miles up the San Diego County coast. Pollutants are also released into the air near the Scripps pier in La Jolla.
Why it matters
The findings show that sewage from the U.S.-Mexico border reaches well beyond the immediate border area, extending the geographic reach of the contamination. Understanding how far the pollution travels helps identify which coastal communities may be exposed.
The study measured sewage-tainted water traveling about 22 miles north from the U.S.-Mexico border along the San Diego County coast. The extraction does not provide a comparison baseline, and the health effects of the airborne pollutants remain unquantified.
The players
University of California, Riverside
A public research university in Riverside, California, known for its environmental and water-quality research programs.
Scripps Institution of Oceanography
A marine science research institute at UC San Diego in La Jolla, widely recognized for its ocean and coastal studies.
The details
Sewage-tainted water moves underwater from the Tijuana River northward along the coast, and after reaching La Jolla, pollutants are released into the air near the Scripps pier. Researchers from UC Riverside and Scripps Institution of Oceanography conducted the study.
Timeline
Study findings on Tijuana River sewage travel were published on November 7, 2026.
Geographic Context
The study builds on Scripps Institution of Oceanography's long-running coastal ocean research by tracing how Tijuana River pollution moves along the San Diego County shoreline. It documents a transport pathway that extends well north of the border.
Residents of coastal San Diego County communities, including areas up to 22 miles north of the border, may face exposure to sewage-tainted water and airborne pollutants. The extraction does not specify safety advisories or protective measures.
The takeaway
Tijuana River sewage is not confined to the border area, so beach visitors and residents along the San Diego County coast should stay informed about water-quality conditions. Monitoring data from local agencies can help guide decisions about recreation near the water.
Further reading
Explore more on Geography to see how coastal pollution patterns shape California's shorelines.
Source note: This article includes information reported by Lodinews.
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