Nine percent of California's beaches were unsafe for swimming at some point last year, according to the Natural Resources Defense Council (NRDC)'s nationwide report "Testing the Waters 2014." That's one percent better than the rest of America's bacterial beaches, on average, so woo.

Nevertheless, there are still some beaches in the Bay Area that are, on occasion, not specifically too good (see list below).

According to the report, many local beaches, for example most of Ocean Beach, are generally bacteria-free, but other beaches frequently tested poorly, particularly on the Bay, where the waters are stiller. The NRDC report explains that stormwater pollution and "untreated sewage spills and overflows are also frequently to blame."

The report uses the EPA's Beach Action Value (BAV) safety threshold, which examines bacteria levels (a.k.a. raw sewage and fertilizer runoff) in beach water samples.

Each beach in the report was tested multiple times last year, and the percentage given to each represents the number of times the beach exceeded the EPA's BAV safety threshold last year.

Here's the list of the beaches that the EPA deemed most unsafe for swimming.

  • Parkside Aquatic Park (San Mateo County): 64 percent
  • Lakeshore Park (San Mateo County): 48 percent
  • Candlestick Point at Windsurfer Circle (San Francisco): 47 percent
  • Mitchells Cove Beach (Santa Cruz County): 42 percent
  • Capitola Beach west of jetty (Santa Cruz County): 33 percent
  • McNears Beach (Marin County): 32 percent
  • Baker Beach, Lobos Creek at lower parking lot (San Francisco): 28 percent
  • Pillar Point near West Point Avenue (San Mateo County): 28 percent
  • Kiteboard Beach (San Mateo County): 23 percent
  • Candlestick Point at Sunnydale Cove (San Francisco): 22 percent
Keep in mind that the number of tests performed varied from beach to beach. For that reason, the alarmingly high percentage cited for Ocean Beach at Vicente Street should be taken with a grain of sand—though it exceeded the EPA's safety threshold 75% of the time, only four samples were taken last year. Other beaches in the study were tested dozens of times.

"The overall trend is that there's a substantial pollution problem," Noah Garrison, staff attorney for the Natural Resources Defense Council's water program, tells SF Gate. You can click through all the test results on the NRDC's report here.