Water Quality
North Coast County Water District provides high quality drinking water to the residents of Pacifica. The San Francisco Public Utilities Commission supplies the water to NCCWD from isolated watersheds in Yosemite National Park and from protected local watersheds. From the source, through treatment and distribution, and finally to the tap, the quality is maintained and protected every step of the way.
The California Department of Public Health and the United States 
Environmental Protection Agency set standards for drinking water quality. To ensure that the water delivered to NCCWD and other customers consistently meets these standards, San Francisco monitors the water at the source and at the treatment plant for a variety of constituents including turbidity (clarity), organic and inorganic chemicals, microbiological quality, mineral content, and radiological quality.
NCCWD monitors the water supply as it enters the system from San Francisco for turbidity and adequate chlorine residual concentration. To ensure that the water remains safe, NCCWD collects numerous samples each week from various locations in the distribution system to be analyzed for coliform bacteria, chlorine residual, pH, turbidity, and temperature. NCCWD employs a trained and experienced analyst who performs these tests at the District's State-certified laboratory.
Every three months, NCCWD monitors the distribution system for trihalomethanes, or THMs, compounds formed when the chlorine used for disinfection reacts with naturally occurring organic compounds found in the source water. This monitoring indicates that THMs in the water are consistently at safe levels throughout the year.
The bottom line: North Coast County Water District consistently provides to consumers high quality drinking water that is safe to drink and meets all standards set by the California Department of Public Health and the United States Environmental Protection Agency.
View the District's Consumer Confidence Report
Blend Change Notice Update - Updated 3/18/2024
Please be advised that there will be a temporary source water blend change on March 21, 2024.
The Harry Tracy Water Treatment Plant (HTWTP) will be going out of service on March 21, 2024 for maintenance and construction projects. At that time, the Hetch Hetchy Aqueduct will return to service.
Typically, we receive our water from the HTWTP located in San Bruno, which is owned by San Francisco Public Utilities Commission (SFPUC). The plant treats and delivers water stored in Crystal Springs and San Andreas reservoirs to customers throughout the Northern Peninsula. On March 21, 2024, we will be receiving water mostly from the Hetch Hetchy Aqueduct with some flow also coming from Sunol Valley Water Treatment Plant (SVWTP). This arrangement is expected to continue until May 1, 2024.
We are monitoring these conditions and will provide updates should significant changes occur. Be assured that in spite of occasional variations in taste or odor, your water meets the highest standards for drinking water. Please call the North Coast County Water District at 650-355-3462 for more information about your water quality or send an email to This email address is being protected from spambots. You need JavaScript enabled to view it. if you have additional questions.
Flushing FAQs
Periodic fire hydrant flushing is necessary to ensure proper functioning of the fire hydrants and to purge the water distribution system of sediment. Residents may experience some decrease in water pressure, as well as possible degradation of water clarity during or shortly after this maintenance program. Questions regarding this important maintenance program should be directed to the Water Quality Department at (650) 355-3462 Monday-Friday 8:00 a.m. – 4:30 p.m.
Q. What can I expect during flushing?
A. If tap water is used during flushing, it could be rust colored and include fine sediment. If your water does become discolored, turn on an outside faucet to clear the water line before doing any cooking, laundry or cleaning. Check the clarity by running cold water for a few minutes, allowing new water to work its way into your pipes. In some cases, you may experience slight discoloration for a few hours. This discoloration only affects the appearance of the water; it does not affect water quality.
Q. What should I do if my water pressure or volume seems low after flushing?
A. Low water pressure is expected during flushing. However, if you still have low pressure or low water volume after flushing, check your faucet and washer screens for trapped debris. If your faucets are clear, and you still experience low pressure, please contact the District to report the issue.
Q. Why does the water look different after hydrant flushing?
A. When a hydrant is opened, there will always be temporary incidences of discolored water containing fine sediment particles. There is no health hazard associated with discolored water. Allow a few hours for discoloration to dissipate. To verify the water has settled, allow your cold water tap to run until clear.
