Los Angeles County beaches showed marked improvement in water quality over the summer months compared with last summer, according to Heal the Bay’s 2011 End of Summer Beach Report Card.

This summer, 92 percent of beach sites statewide received A or B grades, the same total as in last year’s summer report. In L.A. County, approximately 85 percent of beaches received A or B grades, compared with 79 percent last year. Heal the Bay officials said the improvement was due in large part to historically troubled Long Beach scoring its best summer water quality grades to date.

The Santa Monica Pier beach continued its improvement from previous summers with an A grade during dry weather.

In its summer Beach Report Card, the Santa Monica-based environmental organization assigns the A-to-F letter grades to 447 beaches along the California coast, based on levels of bacterial pollution reported from Memorial Day through Labor Day.

“We continue to see water quality improvements at California beaches,” said Mark Gold, president of Heal the Bay. “A sustainable source of beach monitoring funding is critical to ensure that we continue to capitalize on these gains and safeguard the public health of millions of ocean users statewide.”

The Beach Report Card is based on the routine monitoring of beaches by local health agencies and dischargers. Water samples are analyzed for bacteria that indicate pollution from numerous sources. The better the grade a beach receives, the lower the risk of serious gastro-intestinal and respiratory illness to ocean users, according to Heal the Bay.