San Mateo beaches make dreadful list

Heal the Bay rates beaches annually, and all three San Mateo County beaches have received the “Beach Bummer” designation multiple times Poor water circulation yields steady pollution

Three San Mateo County beaches are among California’s most polluted beaches, according to a list compiled by an environmental group.

Erckenbrack Park, Marlin Park and Lakeshore Park all struggle to clear pollution, as they are “enclosed in an engineered patchwork of channels that do not allow much water circulation so pollution is not easily flushed away from the beaches,” states the report from Heal the Bay.

Heal the Bay named all three as “Beach Bummers,” a designation shared with the Santa Monica Pier and parts of Marina del Rey Mother’s Beach (Los Angeles County); Moonstone County Park (Humboldt County); Newport Bay, Vaughn’s Launch (Orange County); and part of the Tijuana Slough (San Diego County). The group rates beaches on a scale of A to F and those with the highest levels of three types of fecal bacteria — including E. coli — make the “Beach Bummers” list.

The most polluted beach, Playa Blanca, is in Tijuana, Mexico. (It is unclear why the group included a beach in Mexico.)

Erckenbrack Park, with “a known record of poor water quality,” and Marlin Park, where the water quality also suffers, are the second and third on the list, respectively. Lakeshore Park is No. 8.

Heal the Bay rates beaches annually, and all three San Mateo County beaches have received the “Beach Bummer” designation multiple times. In recent years, the county has received more “Beach Bummer” designations than any other graded county.

Each of the three poorly rated beaches is located along canals in Foster City that feed into the bay — making it far more challenging to clear pollution than for an ocean beach.

In addition to residual problems clearing pollution, the county

experienced 38 sewage spills into various bodies of water over the course of a year (spring 2021 to spring 2022), with one 2.9 million-gallon spill closing Pacifica State Beach and additional spills in the county of about 400,000 gallons.

The report compiled information for 500 beaches. On the good side, 51 beaches made its “Honor Roll,” but all are in Southern California. That’s partly because many Northern California counties do not track water quality for their beaches year-round, the report said.

Northern California beaches typically were cleaner in the summer than during the rainy winter, the report said, as big storms can impact the presence of bacteria in the ocean.

Funders for Heal the Bay’s report card include the World Surf League and the Surf Industry Manufacturers Association.

Photos by Lea Suzuki / The Chronicle Lakeshore Park beach displays an advisory stating that water levels are tested weekly for bacteria.

A jellyfish floats next to garbage in the water at Marlin Park in Foster City. The beach is rated one of California’s dirtiest by Heal the Bay.

Lea Suzuki / The Chronicle A plastic bottle idles at Erckenbrack Park in Foster City. Erckenbrack Park joins Marlin Park and Lakeshore Park on Heal the Bay’s list of California’s dirtiest beaches.