Ocean, Harbor And Baywater Rain Advisories

During and after a significant rainstorm event, storm drains, creeks and rivers carry floodwaters with urban runoff into local ocean, harbor and bay waters. Urban runoff may include fertilizers, road oils, litter and large amounts of bacteria from a variety of sources, such as animal waste and decomposing vegetation. The levels of bacteria can rise significantly in ocean and bay waters close to discharging storm drains and outlets of creeks, rivers, and streams during and after rainstorms. To ensure that public health and safety is protected, WQ staff advise against body-contact recreational use of ocean, harbor or bay waters where there may be contamination due to storm water carrying urban runoff. The elevated bacterial levels in ocean, harbor and bay waters may continue for a period of at least three days, depending on the intensity of the rain and the volume of runoff.

should avoid contact with any storm drain or creek runoff on the beach during dry or wet weather conditions.

WQ issues a Rain Advisory during or immediately after a rainstorm event that results in measured rainfall greater than or equal to two-tenths of an inch (0.20”). If multiple rainstorm events occur during the 72-hour window of the previous rainstorm, the existing Rain Advisory continues for an additional 72 hours. Rain Advisory information is provided by issuing a Rain Advisory Press Release to media outlets and on the Ocean, Harbor and Bay Water Closure and Posting Hotline at (714) 4336400, Webpage at www.ocbeachinfo.com, and on Twitter http://twitter.com/ochealth.

Upon implementation of the AB 411 Ocean Water-Contact Sports Standards in July of 1999, the WQ Team began issuing Rain Advisories for all coastal ocean, harbor or bay waters in Orange County. The annual report uses data beginning in 2000 when the first full year of the Rain Advisories were issued. Appendix G provides the total number of Rain Advisory Days for each year and the dates the advisories were in effect (2000 – 2020).

Swimmers, surfers and divers should avoid body-contact recreation with Orange County’s ocean, harbor and bay waters during and after a rainstorm event and all beach users