Source Information
Volunteers from Surfrider San Diego’s Blue Water Task Force sample 10 different local coastal water sites every Thursday for Enterococcus, a coliform bacteria indicative of fecal levels in the surface water. This includes beaches, bays, and river outlets. Testing occurs throughout the entire year for all ten sampling sites and samples are processed at one of three labs using IDEXX’s Enterolert, the same test kit used by the EPA to analyze water samples under the Clean Water Act. Within 24 hours, samples are analyzed and shared via the BWTF website, Swim Guide, our social media channels, and our weekly community science and water quality email newsletter, The Weekend Beach Report.
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Results will be displayed on the Swim Guide as one of three colors: green (0-35MPN/100mL), red (104 MPN/100mL-maximum detectable threshold), or gray if there is no current results or no available information. Green signifies that it is safe to recreate in waters at the sampling site due to low bacterial levels. Red means bacteria levels are unsafe. If a sampling site is displayed as red, Surfrider Foundation recommends you do not swim in the area for at least 72 hours. To view results please visit https://bwtf.surfrider.org/report/31 or theswimguide.org.
Although BWTF does not publish beach closures or advisories, our results are regularly consistent with our local Department of Environmental Health’s testing and results. A special status on our sampling sites in San Diego (most likely IB Pier, Seacoast Drive) is typically due to the consistent spilling of sewage near the U.S.-Mexico border. The Tijuana River Estuary is the outlet for overflow from sewage and manufacturing plants that are not able to process excessive amounts of discharge. This frequently happens immediately after a rainstorm. Since the end of 2019, when a rainstorm broke a sewage plant’s system located near the Tijuana River, there has been a constant flow of ~20 million gallons of raw sewage spilling directly into the ocean every day. Due to ocean currents, this sewage moves North and frequently pollutes beaches in San Diego county (Imperial Beach and sometimes Coronado beach).
*MPN/100mL- Most probable number of Enterococcus colony forming units per 100 milliliters
