Water Quality
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Water Quality

The Estero Municipal Improvement District purchases treated water from the San Francisco Water Department and distributes it to Foster City and parts of San Mateo. The District monitors water quality to ensure that it meets state and federal drinking water quality standards.

The San Francisco Water Department also maintains web pages that contain information on cryptosporidium, lead and copper, water quality fact sheets, Annual Water Quality Reports, other reports and links to other web sites.

Click on the following link to view the Water Quality Report for the current year: Know What's in Your Water!

If you have any questions or need additional information regarding water service or water quality, such as reporting a water leak, broken hydrant, or any type of water issue, please contact the Public Works Maintenance Division.


The San Francisco Public Utilities Commission (SFPUC), the City's water supplier, is aware that their customers throughout the Regional Water System, such as The City of Foster City, have recently experienced taste and odor issues with tap water. As part of normal operations, they reduced supply from one part of their system and increased supply from another. This operation can disturb naturally occurring sediment in the reservoirs and pipelines, which can affect taste and odor. The source of the problem appears to have been the compound, Geosmin, that is present in the water from the San Antonio Reservoir. The SFPUC alleviated the problem by taking the Sunol Valley Water Treatment Plant off-line. 

However, due to the inspections and repairs of the Mountain Tunnel pipeline facility, the Hetch Hetchy supply was shut down on January 3, 2017. The Hetch Hetchy supply is estimated to reopen on March 12, 2017. The SFPUC has temporarily discontinued intake from the reservoir, and as a result, the Sunol Valley Water Treatment Plant has been brought back on-line and is being relied on for the duration of the shutdown. The Sunol Valley Water Treatment Plant and the Harry Tracy Water Treatment Plant each provide about 80 million gallons per day as supply to the Regional Water System. The SFPUC started conducting this source water blend change on December 29, 2016.

The change in water blend can alter the water aesthetics (taste, color, or odor), as it is being mixed with water from another source location. It can stir up sediment or algae in the water distribution system. Some people may notice a more earthy or musty taste or odor in the water. This typically subsides after a few days. Customers can try running the cold water for a few minutes to clear out water in the pipes or consider using a filter to alleviate taste or odor issues. The SFPUC is taking actions to mitigate any possible taste and odor issues that might occur with this current blend change. As a precaution, highly sensitive customers are encouraged to seek advice from their health care provider, who may recommend adding filtration devices.

Please note that the water is safe to drink and continues to meet all drinking water standards.

For more information, please click on one of the following links:

 For questions about the water or to report any water quality issues, please call 311.

Last Updated: March 8, 2017

City Hall - 610 Foster City Blvd.
Foster City, CA 94404
(650) 286-3200