Big Rock

Source Information

Beach water is tested either once a week or 5 days a week by the City of Los Angeles Environmental Monitoring Division (EMD), County of Los Angeles Department of Health Services (LACDHS), and Sanitation Districts of Los Angeles County (LACSD). Freshwater swimming holes, falls and creeks are tested by Council for Watershed Health (CWH) approximately once a week in the summer. Sample results are emailed from EMD and CWH to LA Waterkeeper, who updates the swim status and information in Swim Guide. In California, maximum levels for bacteria are established for recreational open beach waters. Single sample maximum levels are 104 Enterococcus /100 ml; and 400 fecal coliform/100 ml; and 10,000 total coliform /100 ml. In waters designated for contact recreation, the median fecal coliform density based on the five most recent samples for any 30-day period shall not exceed 200/100 ml, Fecal and Enterococci density shall not exceed 35/100 ml. Monitoring frequency varies across jurisdictions, most popular beaches are often monitored 5 days a week. In Los Angeles County bacteriological objectives for freshwater recreation are based on e.coli density. The 30 day geometric mean e.coli density shall not exceed 126/100ml and a single sample limit not to exceed 235/100ml. Swimmers are advised not to swim within 100 feet of a flowing storm drain. Swimmers are also advised to stay out of the water for 72 hours following a rain event in the area.