We are proud to provide 100% locally sourced water to more than 191,000 community members in central and southern Marin County. About 75% of our water supply originates from rainfall on our protected Mt. Tamalpais watershed and in the grassy hills of west Marin - 22,000 acres in all - with the remaining supply coming from neighboring Sonoma County’s Russian River water system.  

Rainfall from the watershed flows into the district’s seven reservoirs. The water is treated at our treatment plants before traveling through our extensive distribution system, including 908 miles of pipes, 130 storage tanks and 97 pump stations before making its way to your home or business. It takes 24 hours for water to travel from a reservoir to a treatment plant and then through miles of underground mains into your faucet. Your cost for a gallon of water delivered is less than two cents. 

Follow your water's journey from source to tap

Marin Water takes many steps to ensure the water delivered to your tap continues to meet or exceed federal and state drinking water standards. These steps include carefully managing our watershed lands and reservoirs, treating the water, operating and monitoring a complex distribution system and maintaining and upgrading our facilities. 

Every year, the District conducts approximately 115,000 water quality and process control tests – from watershed to faucet – to ensure your water is safe to drink. This includes ongoing process control testing at our treatment plants as well as laboratory testing. Many of these samples undergo chemical, bacteriological and physical analyses in the District’s water quality laboratory, which is certified by the California State Water Resources Control Board’s Environmental Laboratory Accreditation Program. In addition, the District sends other samples to specialty labs.

Occasionally, during the warmer months, some customers experience a different taste or odor in their drinking water. Some describe the water as tasting and smelling earthy, musty, or moldy. This is caused by naturally occurring compounds produced by algae in our reservoirs. Algae are a natural phenomenon, particularly during the warm summer months, and are a reminder that our lakes are living water bodies. 

During certain times of the year, we may also shift water sources from one reservoir to another to manage our water supply. These operational changes can result in customers noticing changes to the taste and smell of their tap water. These slight changes, which are common in lake water, do not affect the safety of your water. Your water is treated and meets or exceeds all state and federal requirements. 

For those who are more sensitive to taste and odor changes, chilling the water during these periods will help reduce the temporary change in taste or smell of your water. For questions or for more information contact us at 415.945.1550 or at WaterQuality@marinwater.org.

Every year Marin Water cleans some of its water mains to remove built-up sediment so we can maintain the high-quality water you expect from us. 

To clean a water main, we turn on select hydrants along a section of the water main. Water comes out of the hydrants with enough velocity to clean the water main. We also collect water quality samples as part of the water main cleaning process to ensure our water meets the highest standards. 

During the cleaning process, you may notice water in the streets as well as slight drops in water pressure. After the cleaning, you may notice air in your water lines at first, or a brief discoloration of water in your own plumbing. If you notice these effects, we recommend running cold water for a short time to remove any loose sediment in the pipeline that runs from our water main to your home. 

For questions or additional information about water main cleaning in your area, email us at Info@marinwater.org.

Marin Water’s drinking water is clean and safe, meeting or exceeding all state and federal regulatory standards. Filtering is not necessary. For those interested in improving taste, carbon-based filters are recommended.

Please contact us at 415.945.1550 or at WaterQuality@marinwater.org. We are happy to provide assistance or additional information about your water quality.