Public health officials in Los Angeles and Orange counties are asking surfers and swimmers to stay out of the ocean because of the bacteria, debris and trash that washed into the water from this week's storms.
The advisory remains in effect until 7 a.m. Sunday for all Los Angeles County beaches, but it may be extended depending on the rainfall. In Orange County, health officials advised beach-goers to stay out of the water for three days after the latest storm.
As a rule, bacteria can lurk in local waters for at least three days after a significant rainstorm.
Rain intensity and the volume of runoff from storm drains, creeks and rivers can elevate bacteria levels in the ocean.
The elevated levels of bacteria can cause sickness among children and the elderly.
San Diego County officials issued a similar warning Wednesday.
The dock areas at Balboa Bay Club in Newport Bay are closed because of a sewage spill.
The Tijuana Slough National Wildlife Refuge and Border Field Park were closed in southern San Diego because of polluted runoff from the Tijuana River.