(LOS ANGELES) -- Health officials are urging people to stay out of the water at several popular Southern California beaches due to high bacteria levels.
The Los Angeles County Department of Public Health issued an alert cautioning residents to avoid swimming and surfing in the waters at four beaches: Santa Monica Pier in Santa Monica; Mother's Beach in Marina Del Rey; Inner Cabrillo Beach in San Pedro; and Topanga Canyon Beach in Malibu.
"These warnings have been issued due to bacterial levels exceeding health standards when last tested," the health department said.
The four impacted beaches remain open, though the health department warns that ocean water bacteria levels that exceed state standards could cause illness.
The advisories come amid an excessive heat warning for parts of Los Angeles County and ahead of Labor Day weekend.
At least one surfer was not deterred by the health department's warning.
"I've been a surfer for nearly 40 years now and the bacteria levels come and go with storms and other things. And unless there's like a severe sewage spill or something like that, I'm pretty much out there regardless if the waves are good," Richard Evans told ABC Los Angeles station KABC at Topanga Canyon Beach on Tuesday.
Koji Funakoshi told the station his throat hurt "a little bit worse than normal" after surfing at the beach Tuesday morning.
"I think it's better not to be in the water. It's safer not to," Dr. Russ Kino told KABC, warning that you could experience gastrointestinal issues such as diarrhea and stomach cramps.
Most of the region's beaches are not under advisory.
The waters off the Santa Monica Pier and parts of Mother's Beach are among the most polluted in California based on levels of bacteria in the ocean, according to the environmental group Heal the Bay. Santa Monica Pier and a portion of Mother's Beach received Fs in the group's latest beach "report card," released in June.
Topanga Canyon Beach received an A, while portions of Cabrillo Beach received an A and D in the latest report card.