The City of Napa is committed to providing a safe and reliable supply of drinking water that meets all State and Federal health standards.  The Water Division's three treatment plants transform raw source water into clean and safe drinking water using three basic steps - sedimentation, filtration, and disinfection.  The water supply is continuously sampled and tested for contaminants to ensure that health standards are met and that taste, odor, and appearance are optimized.

Reporting a Problem

Before reporting a problem, please note whether your concern is with color, taste, odor, or something other, and be prepared to answer the following questions:

• Is the problem in the hot water, cold water, or both?
• Is the problem observed at all faucets?
• Do neighbors see a similar problem?
• Is there construction activity nearby?

Call Water Division staff at 707-257-9521.

Annual Quality Report 

As required by law, by July 1 each year the City provides its water customers with a summary of any contaminants detected for the previous calendar year.  The 2012 Drinking Water Quality Report is currently available.  Click on the image to view an electronic version (printable PDF).  Alternatively, hard copies are available at the Water Division, 1340 Clay Street and at the Public Works Department, 1600 First Street.  A primary purpose of the report is to provide detailed information regarding contaminants, related potential adverse health effects, and possible sources of contamination.  For 2012, the City met all of the stringent State and Federal standards for finished drinking water and distribution system water.  If you have any specific questions after reading the report, please call the Water Quality Analyst at 707-253-0822 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it them.

Backflow Prevention

To protect the public water mains from potential contamination by non-potable "used water" that could be drawn in during a sudden pressure drop, the City requires installation of a backflow prevention device on new services.  The device must be approved by the California Department of Public Health (CDPH).  To see the current list of approved backflow prevention devices, stop by the Water Division's 1340 Clay Street office, or call the CDPH Drinking Water Program directly at 916-449-5600 to request a copy.  To minimize the visual impact of these devices, consult City of Napa Backflow Screening Guidelines.

All installed devices must be tested annually and immediately repaired if necessary.

        List of Certified Backflow Prevention Testers

For more information, call the Cross Connection Control Program Coordinator at 707-257-9523 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it  them.