The San Diego County Department of Environmental Health and Quality issued a general rain advisory Tuesday to avoid water contact at all coastal beaches and bays due to last night's rainfall.
The DEHQ reminded swimmers, surfers and other water users that rain brings urban runoff, which can cause bacteria levels to rise significantly in ocean and bay waters, especially near storm drains, creeks, rivers and lagoon outlets.
Urban runoff may contain large amounts of bacteria from a variety of sources such as animal waste, soil and decomposing vegetation. Bacteria levels can remain elevated after a rainstorm depending upon the intensity of the storm, volume of runoff and ocean conditions.
While many coastal storm drains have permanent warning signs, additional warning signs are not posted for general rain advisories. Water contact such as swimming, surfing and diving should be avoided during rain and for 72 hours following the rain event.
Additionally, a county-mandated beach closure will remain in place for the Tijuana Slough and Imperial Beach shorelines due to sewage-contaminated flows entering the United States. The water contact closure area includes all beaches from the International Border to 500 feet north of Carnation Avenue. Beach closure signs will remain in place until ocean water sampling results meet state health standards.
Some access roads and trails within the Tijuana River valley may also be affected by sewage-impacted runoff and should be avoided if flooded.