Water Quality

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 continually sampled and tested for contaminants to ensure that health standards are met and that taste, odor, and appearance are optimized.

Throughout the year, we shift water sources from one reservoir to another and change where water is treated to manage water supplies, adjust for customer water demands, and accommodate emergency or maintenance projects. These operational changes may occasionally result in customers noticing changes to the taste and smell of their tap water. Regardless of these seasonal changes, your tap water is safe to drink and currently meets all State and Federal standards.

SPECIAL NOTICE:  Annual Hydrant Flushing Program runs from December 2020 through April 2021. Visit the program's web page for current maps of areas being flushed.

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.

View the City’s 2020 Monthly Summaries of Water Quality Complaints (PDF).

Annual Drinking Water Quality Report

Our drinking water routinely meets or exceeds the stringent water quality standards set by the U.S. Environmental Protection Agency (EPA) and the State Water Resources Control Board. 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.

Find out more about water quality reporting and view current and past issues of our annual Drinking Water Quality Report.