LOS ANGELES — Less winter runoff has allowed visitors to enjoy mostly clean water at California beaches, according to a report released Thursday.
An estimated 93 percent of the 445 beaches along the state's coast that were tested for bacterial pollution from Memorial Day through Labor Day had good to excellent water quality.
It was the fifth consecutive year that beachgoers have seen incremental improvement in beach water quality during summer months.
Three percent — or 14 beaches — that were monitored during the same period last year received poor marks.
The annual beach report card, issued by the Santa Monica-based environmental group Heal the Bay, studied bacteria levels found in water samples taken by local agencies.
Heal the Bay attributed the improved water quality to extremely low rainfall in Southern California and infrastructure upgrades. Lack of rainfall means less urban runoff into the ocean.
Most bacterial contamination occurs during winter, when heavy rains overload storm drains and sewage systems, washing pollutants into the sea. Swimming in polluted waters can cause ear infections and gastrointestinal problems.
The results bode well for the upcoming summer beach season after a drier-than-normal winter in Southern California.
Among the state's 10 beaches with the worst water quality, four were in Los Angeles County, the report found.
Testing showed the dirtiest beach was at the city of Avalon on Santa Catalina Island off Southern California. The environmental group said it expects water quality to improve once Avalon completes an upgrade of an aging sewer system that has been blamed for persistent high pollution levels.
The second-most polluted beach in the state was Cowell Beach in Santa Cruz County followed by Poche Beach in Orange County.
Heal the Bay has published its beach report card for the past 22 years. The latest report included water sampling that was done between April 2012 and March 2013. The environmental group said grades are updated weekly on its website.
It has been lobbying for the restoration of $10 million in federal funds used to monitor beach water quality. The group said many counties in the state depend on those funds to do testing.
Besides California beaches, the new report also includes beaches in the Pacific Northwest where the water quality was excellent in the vast majority of cases.