The Environmental Health Division of the OC Health Care Agency advised swimmers to stay out of the ocean and nearby bays for the next few days because of possible urban runoff from this week's rainstorms.
"Levels of bacteria can rise significantly in ocean and bay waters, close to storm drains and the outlets of creeks and rivers during and after rainstorms," according to an advisory from the agency.
Elevated bacteria levels along Laguna Beach, Huntington Beach and Newport Beach may continue, depending on the volume of runoff, the agency said.
Rain pelted Orange County on Monday and into Tuesday.
As of 3:30 p.m. Tuesday, Huntington Beach had amassed 2.01 inches since the storms began, the
Newport Beach's total was estimated at 1.06 inches, while Laguna Beach had 0.94 inches, the weather service said.
Derek Schroeter of the National Weather Service said: "Coastal Orange County has received the most rainfall out of our forecast area. It's been more active than usual. We are on a record-setting pace for the amount of precipitation. It's been a much-needed wet year."
Kevin Onuma, deputy director of OC Public Works, said the heavy rainfall in January was "the type of rain you only expect to see every 50 to 100 years."
However, the county is expected to dry out Wednesday and Thursday, with skies generally clear, the National Weather Service said.
Temperatures are expected to be in the 60s on Wednesday and climb into the mid-70s inland on Thursday.
Another storm will make its way to Southern California starting Friday, causing a drop in temperatures, said National Weather Service meteorologist Brett Albright.
Friday's highs will be in the mid-50s across Orange County, with "heavy clouds and rain rolling in through the afternoon and early evening," Albright said. The rain should dissipate through the night, he said.
There is a slight chance of showers Saturday morning, with temperatures in the 60s, the weather service said.
Skies are expected to be clear Sunday, with highs in the mid-60s to low 70s.
"Once next week begins, we're looking at more Santa Ana wind conditions in the southern part of the county," Albright said.