Did You Know San Mateo County Tests 43 Beaches and Creeks Every Week? Register!

Water samples from natural recreational waters in San Mateo County are sampled each week for concentrations of indicator bacteria.

If concentrations of indicator bacteria exceed State or County standards, the area is posted to warn users that they may become ill if they engage in water contact activities in the posted area.

As a reminder, we advise against swimming in ocean waters during and 3 days after a storm. When swimming in ocean waters, always stay at least 300 feet from a flowing storm drain or creek mouth.

Join the Monday morning San Mateo County Volunteer Sampling Team and help protect beach users.  For more information, see the Volunteer Opportunities in the FAQ section below.

To view current data and posted sites, please view the map here: San Mateo County Interactive Beach Map 

The State Water Resources Control Board has statewide recreational water sampling locations and historical data available to the public: Safe to Swim Map

IMPORTANT NOTICE: 

The following list was last updated Wednesday, July 28, 2021 based on samples collected Monday, July 26, 2021.

Certain beaches and creeks may not have been sampled this week due to closures or inaccessibility. Sites that were not sampled are shown in gray on the San Mateo County Interactive Beach Map (We are currently experiencing technical difficulties with the beach map. We are working to resolve this issue as soon as possible).

The following locations have elevated levels of indicator bacteria and are posted with warning signs.

OCEAN BEACHES

• Linda Mar Beach at San Pedro Creek
• Pillar Point #8 (Maverick’s Parking)
• Pillar Point #7 (Surf-West Point Ave)
• Pillar Point #9 (Outer Harbor)
• Francis Beach (Kelly Ave)

CREEKS (WHERE THEY MEET OR CROSS THE BEACH)​

• Pilarcitos Creek
• San Gregorio Creek
• Pomponio Creek*
  • *This creek was not sampled due to it not breaching to the ocean. It will remain posted as a cautionary measure

BAY BEACHES

• Erckenbrack Park

Signs limiting the recreational use of these waters have been posted and will remain in place until the level of indicator bacteria drop below State thresholds.  You can also check for closures and postings on San Mateo County’s Beach/Creek Posting Hotline announcement at (650) 599-1266.  Read on for more information on the County’s Recreational Water Quality Monitoring Program, including:

• Description of the County’s Monitoring Program
• Posting Criteria
• Explanation of Signs
• What Waters to Avoid
• Description of Exposure Symptoms
• Volunteer Opportunities

Recreational Water Quality Monitoring in San Mateo County

Thousands of people use San Mateo County swimming areas annually. On any one day, people can be found swimming, surfing, body-surfing, diving, or just walking through the water’s edge at any of the Ocean or Bay water beaches in San Mateo County.

Generally, these waters are clean and safe for swimming. However, to ensure public health and safety,  San Mateo County Environmental Health Services, with the help of volunteer samplers, regularly test these waters for contamination. If problems are found the public is notified and steps are taken to control the source of contamination.

FAQ

How often does the County test the water?

What criteria are used to evaluate the sample results?

What do the posted signs mean?

What waters should I avoid?

Can I get sick from swimming in the ocean or streams?

What should I do if I think I have gotten sick from the water?

Volunteer Opportunities