Bolinas Surfacing Wastewater

How and when was this issue discovered?

County staff observed moisture and liquid seeping from the cliff face while doing site visits for permit applications during the week of September 3, 2024. The seepages showed evidence of being from wastewater, and further testing is consistent with that initial conclusion.  

What is the cause of this issue?

The cause of the surfacing wastewater is not fully known at this time. What happens underground is complicated and it is difficult to pinpoint a single cause of the issues. We know that the sampled water tests are indicative of wastewater. While most of the homes on Bolinas Mesa are dependent on septic systems, testing has been inconclusive that this might be a source.  Additional factors may be contributing to the surfacing wastewater. Determining the cause may require consultation from outside experts.  

How extensive is the seepage problem? Are there specific areas of Bolinas that are more affected than others?

Wastewater is visibly seeping from the Bolinas Mesa bluffs in multiple locations as observed from accessible portions of beach, affecting an area over a mile long between Rosewood Road and Canyon Road, southwest of Brighton to south of Agate Beach. The volume of seepage varies by location.

What agencies are involved in investigating the matter?  

The County consulted several departments on this issue: Health and Human Services, Community Development, Fire, Parks, Emergency Management, and the County Executive’s office.  Local partners at the Regional Water Quality Control Board, Bolinas Community PUD and Bolinas Fire are also involved.   

Which parts of Bolinas Beach are open? 

All of Bolinas Beach is now open, though an advisory has been issued to warn visitors of potential contamination and possible rockfalls from bluffs, especially in the areas southwest of Brighton to south of Agate Beach.

What factors influence the beach access?

There are two different factors that determine which part(s) of the beach may be accessible:   

• Presence of wastewater on beach: While there is no active closure, visitors should be aware of wastewater seepage from the Big Mesa bluffs in some areas. Testing indicates high bacteria levels, including coliform, E. coli, and enterococcus, which could pose health risks if contact occurs. 
• Ocean water quality: Open areas, including Agate Beach and the beach between Brighton and Wharf (toward downtown), may occasionally be subject to water quality advisories. These advisories are issued if weekly water quality testing shows bacterial levels exceeding health standards. Beaches remain accessible during an advisory, but water contact is strongly discouraged due to potential health risks. 

Under what authority can a health officer close a beach?

In California, the authority for beach closures by a Health Officer generally falls under the California Health and Safety Code. Specifically, Health Officers can use the following provisions:

• California Health and Safety Code Section 101040 gives local health officers the power to take action to protect public health and safety, including closing public areas if there is a health risk.  
• California Health and Safety Code Section 120175 allows health officers to take measures to prevent the spread of communicable diseases, which could include closing public areas like beaches during health emergencies. Further, California Code of Regulations (CCR) Section 7957 “Physical Standard” states that “No sewage, sludge, grease, or other physical evidence of sewage discharge shall be visible at any time on any public beaches or water-contact sports areas,” which means that the County is obligated to address the condition of wastewater discharge on the cliffs and beach.  

The County is coordinating with the California Coastal Commission on the beach closure and will follow all applicable requirements.   

Is it safe to walk down the beach at the tide line, if I stay away from the bluffs?

Visitors should exercise caution. Even if visible wastewater is avoided, contamination can occur from runoff or unseen sources. Beachgoers, including pets, may face health risks if they come into contact with potentially contaminated areas. Be sure to wash hands after coming into contact with water or soils.  

How often is the seawater tested at Bolinas Beach?

We test the water at Bolinas Beach every week from April to the end of October each year.  

Why is the seawater tested? 

The seawater was tested for bacteriological quality, specifically three fecal indicators: Total Coliform, E. coli, and enterococcus. Coming into contact with or accidentally swallowing water with high levels of bacteria while swimming or doing other water activities can be harmful to both people and animals.

Marin County Environmental Health Services has monitored ocean, bay and freshwater sites in Marin County since 2003. Samples are collected from 31 locations once a week between April and October. This long standing service ensures our local beaches meets the California water quality standards for recreational water contact and helps safeguard public health.

Is the water quality of the ocean seawater at Bolinas Beach safe to swim in?

This may vary week-to-week. Recent tests show that water meets State standards for recreational use. However, In 2024, Bolinas Beach's ocean water quality has not met State standards on two occasions:  

• For the October 15 test, the single-day sample result for enterococcus was 265 MPN/100 mL, exceeding the recreational water contact limit for marine water, which is 104 MPN/100 mL.  
• For that September 17 test, the single-day sample result for enterococcus was 262 MPN/100 mL. However, the results for total coliform and e.coli were under the recommended recreational water limits.  

In those cases, advisories were issued, and water contact was discouraged. Visitors should always use caution and check for any active advisories before entering the water.

What happens if water samples do not meet State standards?  

If the water samples ever go above the safe limits set by the State of California for recreation, Environmental Health Services will issue an advisory (warning) and signs will be posted at the beach. This advisory will stay in place until new tests show that bacteria levels are safe again.  

When an advisory is in effect, water contact is discouraged. People should avoid activities where they might swallow water, such as swimming, surfing, diving, and kayaking. Pet owners are also advised to keep their pets out of the water during an advisory to prevent them from drinking contaminated water. 

Where is the seawater tested at Bolinas Beach? How can I view the results? 

Water samples are obtained at Bolinas Beach near the channel (specifically, Latitude 37.90835046, Longitude –122.682137).  You can view ongoing testing results on the Beach Water Quality Information webpage.  In addition, you can contact us to be added to a listserv to receive weekly test results by email. 

What exactly was found in the wastewater discharge along the Bolinas mesa?  Were there any specific contaminants identified?

Seepage was observed in the bluffs and near the beach edge below Canyon/Ocean Parkway/Terrace. Water quality tests were performed on September 5th at several locations on the bluffs below Ocean Parkway/Terrace and Canyon Road. Results were positive for ammonia, coliform, E. coli, and enterococcus. These results indicate the liquid is likely wastewater and could pose health concerns. Additional visual observations were made between Agate Beach and the sampled locations that appear to be wastewater. More testing would need to be conducted to confirm.

Is my tap water safe to drink?

The majority of Bolinas residents receive drinking water from Bolinas Community Public Utility District (BCPUD). BCPUD has confirmed that their water is tested weekly and comes from a source outside the mesa. Anyone who receives BCPUD drinking water may continue use tap water as usual. 

What can residents who rely on drinking water wells do to stay safe?

If you’re unsure about the quality of your well water, you should rely on bottled or boiled water for drinking. You can test your water independently; if drinking water wells have elevated levels of coliform or E. coli, you should consult Marin Environmental Health Services.

What potential health risks could this pose to residents, either those visiting the beach or those using well water?

Contaminated water can have harmful effects on both humans and animals. Drinking or coming into contact with contaminated water can cause infections such as gastrointestinal illnesses, including diarrhea, nausea, and vomiting. Besides pathogens, contaminated water can introduce chemicals or toxins into well water, potentially leading to long-term health problems if consumed over time. 

Have there been any reports of illness among residents or recent visitors to the Bolinas area?

At this time Public Health has not confirmed any illnesses specifically linked to exposure to contaminated water. Illnesses caused by contaminated water can be due to a wide range of pathogens (bacteria, viruses, parasites) and can present with symptoms similar to many other illnesses. Symptoms of contamination-related illnesses can appear days or even weeks after exposure. This delay makes it difficult to directly link the illness to a specific exposure event. 

What should I do if I believe I have been exposed to wastewater?

Talk to your doctor or nurse about any symptoms of being sick from contaminated water. In addition, you can report your illness via Marin County Public Health’s Waterborne Illness Report Form. 

Should people who live along the ridge of Bolinas Mesa -- aligning with the beach closure -- refrain from certain activities? 

Mainly stay away from the bluffs: It is advised not to climb or walk on the cliff areas; cliff sides are unstable. 

How can I stay informed of updates on this subject? 

Follow this webpage or subscribe for periodic email or text updates from the County.