More than 95% of Orange County beaches received A grades for their water quality this summer — except for Little Corona Beach in Corona del Mar.
The beach received a C in Heal the Bay's End of Summer Report Card, which resulted from the environmental group collecting water quality data at more than 640 locations on the West Coast between Memorial Day and Aug. 21.
Little Corona is an exception to the norm in California, specifically Orange County, which saw a 3% improvement this summer compared to the same period a year ago, according to Heal the Bay's website.
The beach was one of only six statewide, and only one in Orange County, that received a C, according to the website.
The C grade could reflect Little Corona's location near the Bulk Gully Reserve's outlet, said Newport Beach City Councilwoman Nancy Gardner, whose district covers CdM and Newport Coast.
"Unlike other beaches in Newport that are right on the ocean or [Balboa Peninsula], this is the only one near a coastal canyon, so you're going to have runoff," she said.
But the C rating doesn't necessarily mean the water is off-limits, said Amanda Griesbach, a Heal the Bay water quality scientist.
"A C grade means a swimmer might want to pick a beach with a higher score, but just because a beach has a C doesn't mean you will get sick if you go in the water," Griesbach said.
Ninety-eight of 102 county locations received an A or better, including beaches in Newport, Huntington Beach and Laguna Beach that earned A+ marks, according to the website and statistics provided by Griesbach.
Local beaches that received A+ ratings include Newport's The Wedge and Balboa Beach Pier area, Bolsa Chica State Beach in Huntington Beach, Sunset Beach to the north, and El Moro and Main beaches in Laguna, according to the statistics.
Little Corona dropped a grade from the 2012 End of Summer Report Card, while Garnet Avenue Beach in Newport Bay jumped two letter grades, from a C to an A+, statistics showed. In Laguna, Aliso Creek outlet, which runs into the ocean, received an A this year compared to an A+ for summer 2012.
The agency assigned grades A through F based on bacteria pollution data provided by more than 20 organizations. The report does not measure the amount of trash or toxins at beaches.
Heal the Bay also posts weekly water quality information, updated with the most recent available grades every Friday at http://www.beachreportcard.org.
Little Corona received an F for data submitted Aug. 7, collected from five samples in the previous 30 days, Griesbach said.