Six beaches in San Mateo County rank among the 10 most polluted in California in an annual water quality survey by an environmental advocacy group.

Heal the Bay’s Beach Report Card, released Saturday, graded the San Mateo County beaches as the third through eighth poorest based on bacteria levels during summer dry weather. 

The so-called Beach Bummers are:

3. Erckenbrack Park, Foster City

4. Linda Mar Beach at San Pedro Creek, Pacifica

5. Parkside Aquatic Park, San Mateo 

6. Pillar Point Harbor, Capistrano Road Beach, Half Moon Bay

7. Pillar Point Harbor, Harbor Beach, Half Moon Bay

8. Marlin Park, Foster City 

San Mateo County Health regularly samples and tests the water for safety. A spokesman, Faizus Amin, declined to comment on Heal the Bay’s report, deferring to officials in the individual cities.

Ranking worst and second-worst are Playa Blanca in Tijuana and Santa Monica Pier in Los Angeles, both impacted by storm drains.

The ninth and 10th worst beaches are San Diego’s Tijuana Slough at Tijuana River Mouth and Humboldt County’s Clam Beach County Park at Strawberry Creek.

The 21 best beaches on the organization’s Honor Roll are in Los Angeles, Orange, San Diego and Santa Barbara counties. No Bay Area beaches made the list.

“For more than 36 years, Heal the Bay’s Beach Report Card has helped translate bacterial monitoring data into accessible public health information across the West Coast,” the Santa Monica-based organization said in a press release.

Heal the Bay recommends these precautions before entering recreational waters:

  • Avoid swimming within 72 hours after rainfall
  • Stay away from storm drains, river outlets, and enclosed stagnant waters
  • Always check current water quality conditions before entering the water