News Details

SFPUC Water Supply Blend Change

Source Water Change from the City's Water Supplier 

From January through early March, the City's water supplier, the San Francisco Public Utilities Commission (SFPUC), will be delivering water from local surface reservoirs instead of our typical supply from the Hetch Hetchy Reservoir.
This is necessary to accommodate inspections and repairs of the Mountain Tunnel pipeline that delivers water from the Hetch Hetchy Reservoir.

During this period, SFPUC will provide its wholesale customers (cities including Palo Alto, counties and water districts on the Peninsula) with treated water from the Sunol Valley and Harry Tracy Water Treatment Plants.

Visit our water resources page at for details on the water quality parameters anticipated as a result of this blend change.


Potential Change in Taste, Color or Odor

A 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 (not hot) for a few minutes to clear out water in pipes or consider using a filter to alleviate taste or odor issues.

SFPUC has told its wholesale customers that the agency will do all it can to mitigate taste and odor issues with this current blend change. The City of Palo Alto Utilities (CPAU) will also take action as necessary to try to alleviate any local issues in the City's distribution system. Curious about the blend event from early December that caused some concern about a more significant change in taste and odor? Read an update from SFPUC here:

CPAU and SFPUC test your water daily to ensure it meets drinking water quality standards. We recognize that changes in water aesthetics can be worrisome and will continue to monitor conditions very closely. Please contact our Water Transmission staff at (650) 496-6967 if you have any questions or concerns. You can also email us at

Highly Sensitive Customers

Since occasional minor fluctuations in water quality can occur, we encourage people who may be vulnerable to drinking water contaminants to seek advice from their health care provider, who may recommend taking precautionary measures such as adding filtration devices.

Palo Alto Water Quality
CPAU and SFPUC are required by law to adhere to strict health and safety standards for potable drinking water. Every year we publish a Consumer Confidence (water quality) Report, which informs customers about the City's water quality. General questions or concerns? Call us at (650) 329-2161 to report issues or request information.

Annual Consumer Confidence Report
Your water has a variety of physical, chemical and biological elements that are described in more detail in our Consumer Confidence (water quality) Report. This report is updated every year and made available to our utility customers.

Visit our water resources page at for more information on Palo Alto's water quality.

Last Updated January 10, 2017