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 with your Drinking Water

Before reporting a problem, please note whether your concern is with the water's 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 Drinking Water Quality Report 

2015AQRAs 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 2015 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 2015, the City met all of the stringent State and Federal standards for finished drinking water.  In the distribution system however, select areas did not meet the recently adopted standard (based on annual average) for Stage II of the Disinfection Byproduct Rule (DBPR-II) at all times throughout the year.  Informational notices were sent directly to affected customers to reflect disinfection byproduct information for the affected monitoring periods.

If you have any specific questions after reading the Drinking Water Quality Report, please call the Water Treatment Manager at 707-253-0822 or This email address is being protected from spambots. You need JavaScript enabled to view it. them.  NOTE: This report is for calendar year 2015 only.  Since April 2016, all areas of the distribution system are meeting the DBPR-II standard. 


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 State Water Resources Control Board.  To see the current list of approved backflow prevention devices, stop by the Water Division's 1340 Clay Street office, or contact the State Board's Division of Drinking Water directly at 916-449-5577 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 email address is being protected from spambots. You need JavaScript enabled to view it. them.