California residents who endured flooding, mudslides and evacuations during a week of heavy rain have another problem: contaminated water and fouled beaches.


A firefighter helps a woman from her vehicle in a flooded street in Los Angeles. The tail end of a week-long storm in Southern California buried cars in mud and threatened dozens of homes. ((Mike Meadows/Associated Press))

The rain washed trash, pesticides and bacteria into waterways, prompting health warnings. Four beaches were closed in Northern California's San Mateo County and another 19 kilometres of beach from Laguna Beach to San Clemente in Southern California's Orange County were off-limits because of sewer overflows.

While the rain eased on Wednesday, the danger was not over for foothill residents living below wildfire-scarred hillsides.

"The ground is so saturated it could move at any time" and the threat will remain for several weeks, said Bob Spencer, spokesman for the Los Angeles County Department of Public Works. 

More than 200 homes were ordered evacuated for more than 24 hours in La Canada Flintridge and La Crescenta, suburbs of Los Angeles below steep hillsides that burned in 2009 and where mudslides inundated homes and backyards in February.

Warnings to stay away from beaches

After days of relentless rain, long-awaited sunshine was finally in the forecast for Thursday, but officials said Californians may want to resist the urge to head to the ocean.

"It can be very nice the next day and everyone says, 'This is great! This is a beach day,"' said Jonathan E. Fielding, director of the Los Angeles County Public Health Department. "It could well be, but we will be monitoring and testing water and we won't recommend people go back there until we're sure it's safe."


City of Redlands firefighter Engineer Chris Randolph and Redlands Quality of Life employee Jeff Standfield rescue a stranded woman from her truck after she was caught in a flash flood on Wednesday. ((Mark Zaleski/The Press-Enterprise/Associated Press))

Experts normally recommend waiting 72 hours after a storm before getting in the water, though in this case some are saying five days might be wiser. The contamination in some areas could last for weeks because of the especially heavy rains.

Mark Gold, president of Heal the Bay, a Santa Monica based group that monitors and grades beach water quality said more rain causes more pollution to get flushed into the region's water system.  

"Literally every beach gets an 'F' when we get a rain storm like this," he said. "It's big enough to pollute each and every beach in L.A. County. It's a pretty extraordinary event when we have rain like this."

Sixty people were rescued and more than 30 homes evacuated Wednesday when water surged through Dove Canyon, a gated Orange County community.

In Highland, about 105 kilometres east of Los Angeles, two creeks overflowed, swamping as many as 20 homes in up to 90 centimetres of mud. Up to 40 homes and around 100 residents were evacuated.

In San Diego, the first floor of the Premier Inn in the city's Mission Valley flooded, forcing guests to the second floor where lifeguards were sent to rescue them, police said.

The storm weakened as it moved eastward, but floods still washed away homes in Arizona and inundated parts of Nevada and Utah.

The low-pressure system could reach the Gulf Coast by Saturday with some rain, forecasters said.