Joy Aoki/Heal the Bay
Heal the Bay's 22nd Annual Beach Report Card, issued Thursday, found nine of California's 10 dirtiest beaches -- the "Beach Bummers" -- are in Southern California. Avalon Beach on Catalina Island, pictured here, is the worst offender.
Urban runoff dumped into the ocean, corroded sewer and septic systems, and decomposing kelp and algae – these are things that make water quality on California's glorious coastline less than stellar.
A Santa Monica-based environmental nonprofit that annually monitors and rates the cleanliness of the state's beaches calls the dirty ones "beach bummers."
This year, seven of the 10 beaches on the California Beach Bummers list are in Los Angeles County, which typically has some of the dirtiest surf in the state. Two of the least clean beaches were in Orange County, and just one was in Northern California – in Santa Cruz. Many of them are repeat offenders.
"Unfortunately, some of them are still beach bummers after many years," said Kirsten James, director of water quality for Heal the Bay.
The group issued its 22nd Annual Beach Report Card on Thursday. The report assigns A-to-F letter grades to more than 400 beaches along the state's coastline based on water pollution levels during both dry and wet-weather months.
Overall, 407 of 441 California beaches received an A or B grade on the report -- and James said there are many success stories on the list.
Almost all of the worst performers were in densely population Southern California. Five of the 10 worst were in Malibu.
Here's Heal the Bay's Top 10 Beach Bummers list, starting with the most polluted:
Beaches with F grades often have problems with runoff from developed areas, or are near aging sewer or septic systems. Avalon Beach on Catalina Island, which has been on the Beach Bummers list 11 times since 1999, will likely see its corroded sewer system cleaned up in future, James said.
Dirty water is a concern for swimmers, surfers and general beachgoers because it can make those who play in it sick – with a gastrointestinal infection, ear infection or rash, for example.
Heal the Bay cautions beachgoers not to swim within 100 feet of a storm outlet or stream.
"A day at the beach shouldn't make anyone sick," James said.