While still having some of the lowest summer water quality in the state, Los Angeles County beaches showed some improvement from the previous summer, according to the End of Summer Beach Report Card released by Santa Monica-based Heal the Bay.

Through its summer report card, the environmental organization assigns an A to F letter grade to 458 beaches along the California coast, based on levels of bacterial pollution reported from Memorial Day through Labor Day. This summer, 92 percent of sites received A or B grades during the high-traffic beachgoing season, a slight increase from last year, when 91 percent of beaches received high marks.

California’s persistent and ongoing low rainfall totals, which limited polluted urban runoff in storm drain systems, were a key factor in better water quality, Heal the Bay officials said. Enhanced infrastructure at several sites also led to rising grades.

Only 36 locations in the state received fair-to-poor water quality grades, roughly eight percent of all graded beaches. Some 21 beaches received failing grades statewide, including ten in Los Angeles County.

Water samples are analyzed for bacteria that indicate pollution from numerous sources. The better the grade a beach receives, the lower the risk of illness to ocean users.

“Record low rainfall has helped maintain great water quality at the vast majority of California’s beaches for the third summer in a row,” said Mark Gold, president of Heal the Bay. “But we can’t become complacent in our efforts to improve water quality in the summer season. We need long-term funding for beach monitoring and to ensure that problem beaches are safe for swimming every summer.”

In Los Angeles County, only 80 percent of the 81 beaches received A or B marks, according to the report. But the ten beaches in the county that earned F’s during the summer marks an improvement from last summer, when 19 percent of sites received failing grades.

Santa Monica Bay monitoring locations also fared notably better than last summer, exhibiting water quality of 91 percent A’s and B’s compared to last year’s 86 percent.

A few Santa Monica Bay beaches still regularly exceeded newly adopted bacteria standards from April 1st to September 3rd. Santa Monica Pier, Dockweiler State Beach at Ballona Creek, Surfrider Beach in Malibu, Topanga State Beach and Redondo Beach Pier were the worst offenders, the report shows.