Beach Water Quality Monitoring Program
You may be surprised to learn that Tomales Bay is an impaired water body, from pollution that generally comes from agriculture, septic systems, and road runoff, causing our watersheds at times to be unsafe for recreation and shellfish consumption. Every year, the County of Marin samples the Tomales Bay watershed April through October as part of a Beach and Ocean Monitoring Program, to check for high levels of harmful pathogens that may cause people to get sick. The results of these samples are published in the annual Beach Report Card by our friends at Heal the Bay, and we started sharing this data through our social media to advise the public when water contact in some of our favorite beaches should be avoided. In 2020, we restarted the sampling program at Drakes Estero and Drakes Beach—in partnership with the County of Marin and the Point Reyes National Seashore—to ensure recreational water quality samples are being collected to create a long-term dataset so we can advocate to ensure healthy and clean watersheds.
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Marin County Environmental Health Services has monitored 27 ocean, bay and freshwater sites in Marin County since 2003. Samples are collected once a week from April 1 through October 31 to determine if a beach meets the California water quality standards for recreational water contact.
If the water quality results exceed California standards for public health exposures, the County and partners will post a warning notification to inform the public. The California Department of Public Health advises beach users to avoid contact with the recreational waters where warning signs are posted. People in contact with the elevated bacteria levels in recreational waters may become ill. Advisories are provided for informational purposes only and are based on one sample per week therefore they do not provide current conditions. Water sample processing requires 24 hours so the information is at least one day old when posted.
The water samples are processed by the Napa-Solano-Yolo-Marin County Public Health Lab. The tests utilized, quantify the most-probable number of Total Coliform, E. coli, and Enterococcus bacteria present in the water sample. The water samples represent a "snap shot" in time. The bacteria themselves are generally not pathogenic, but are used as indicators of the potential presence of other pathogenic bacteria that are linked to human illness.
Check out the County of Marin Environmental Health Services webpage for more information.
Sampling Schedules
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We collect weekly samples at Drakes Beach and Drakes Estero and the Seashore collects a monthly sample at Abbott’s Lagoon measuring fecal indicator bacteria. EAC’s office is the pick up location for samples that are processed at the Napa-Solano-Yolo-Marin-Mendocino County Public Health Laboratory.
Weekly samples results are posted to the County website and we share social media alerts on water bodies in coastal West Marin that exceed public health limits in order to raise public awareness of the health impacts of water contaminated by fecal indicator bacteria.
If a weekly sample exceeds public health limits, the County and the Seashore will post warning signs to avoid recreational water contact.
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We collect monthly samples at Drakes Beach and Drakes Estero and the Seashore collects samples at Abbotts Lagoon measuring fecal indicator bacteria. Additional samples are collected following a projected 1 inch of rainfall (dependent upon laboratory access). We partner with NPS in couriering the “off season” samples to the Marin County Public Health Lab for processing at the Napa-Solano-Yolo-Marin-Mendocino County Public Health Laboratory.
If an “off-season” sample exceeds public health limits, the County and the Seashore will post warning signs to avoid recreational water contact until a new sample is collected and the results are within public health limits.
Water Quality Results
County of Marin posts the weekly sampling results to their website. We have embedded the County’s data for quick reference of the weekly results below.
Heal the Bay Beach report cards: Beach Report Card Year 2022-2023
Interested in our Advocacy?
To protect water quality, it’s critical to have long-term data sets to understand where and when pollution may be impacting beneficial uses. In 2017, we were surprised to learn that the water quality sampling at public beaches within the Point Reyes National Seashore stopped in 2013. At that time, the Seashore was undertaking the controversial plan to updated their General Management Plan in a public process that to considered whether beef and dairy ranching operations could continue to operate on public lands. For EAC, the lack of recent water quality data to inform the plan was concerning. At a minimum, recreational water body sampling should be happening.
As a local grassroots nonprofit, we were able to organize a partnership between the County of Marin Environmental Health Services and the Point Reyes National Seashore to restart the sampling program. In the first two years of the program, EAC provided the funding, staff, and volunteers to collect weekly water samples at Drakes Beach and Drakes Estero. In 2024, the Point Reyes National Seashore financially supports the lab fees and EAC continues to help with collection of samples throughout the year with our staff and volunteers.
At the same time, EAC effectively advocated to the California Coastal Commission to include to require a comprehensive water quality sampling program and annual report as a requirement of the Commission’s approval of the General Management Plan Amendment in 2020. This helps to ensure long-term monitoring data at multiple sites throughout the Seashore are being sampled year-round that will inform beef and dairy ranch operational management strategies.
Read the below blog articles dedicated to the Point Reyes National Seashore’s General Management Plan Amendment and its implementation to ensure water quality protections of California’s coastal resources and water quality:
California Coastal Commission's Federal Consistency Determination, December 2020
Coastal Commission Consistency Determination, April 2021
Coastal Commission Approves Seashore’s Plan on a Slim (5-4) Margin, April 2021
Seashore Finalizes Plan for Future Ranching Leases, October 2021
Coastal Commission Rejects Seashore's Request to Delay Water Quality Strategy, March 2022
Coastal Commission Rejects Seashore’s Water Quality and Climate Action Strategies, April 2022
Seashore's Water Quality Plan Under Review, September 2022
Coastal Commission Narrowly Approves Park’s Water Quality Plan, October 2022
Gifts to our public lands fund help to support programs like our recreational water quality program.
Costs for this program include mileage and personnel costs for staffing to collect samples. Samples are collected by our interns and trained EAC team members.
In 2022, program costs = $1,500.00
