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The original item was published from 6/30/2023 1:13:14 PM to 7/7/2023 3:20:59 PM.

News Flash


Posted on: June 30, 2023

[ARCHIVED] Annual Drinking Water Quality Report

Annual Drinking Water Quality Report

English and Spanish versions of the annual Drinking Water Quality Report are posted online in the Water Quality section at A message on recent water bills alerted customers of the report’s direct web address. Along with summarizing regulated substances, the report describes our source waters, the importance of protecting our watersheds, and water conservation tips. For ongoing monthly test results and more details about the regulatory standards that ensure public health, visit our Sampling & Testing page at

In calendar year 2022, City of Napa tap water met all stringent U.S. EPA and State health standards except for trihalomethanes (THMs) in a limited area of our distribution network. 

A single sample location on Darms Lane that serves eleven customers exceeded the limit for total THMs in April 2022 as a result of increased organic loading in source water and reduced customer demands. Flushing improved the water quality and returned the location to compliance in subsequent sample collections. 

Printed copies of this Drinking Water Quality Report will be mailed upon request by calling 707-257-9521. Printed copies may also be picked up at the Utilities Department, 1700 Second Street, Suite 100, or at the Finance-Collection windows in City Hall, 955 School Street.

The City continues to primarily use the electronic distribution method for this report, saving resources and ratepayer funds while still communicating to customers about the health and safety of their tap water.

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