Water Quality and Backflow Prevention
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.
Constantly delivering tap water to all of our customers requires constant vigilance of our system of treatment plants, pipelines, storage tanks, and reservoirs. We are always balancing our water supplies, operations, and facilities to keep water flowing to you.
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 can result in customers noticing changes to the taste and smell of their tap water.
- Regardless of the unpleasant odor, your tap water is safe to drink and currently meets or exceeds all State and Federal standards.
- We are aware of the unpleasant odor and have made the following operational changes:
- We have completed major rehabilitation of our filters and brought our Milliken Water Treatment Plant online to supplement additional water system demands.
- We are performing additional algaecide treatments to Lake Hennessey.
- We have switched as much production as possible to the EIB Jamieson Canyon Water Treatment Plant.
- The warmer weather has increased algal growth in Lake Hennessey. Although algae is removed by the water treatment process, it can leave behind musty or earthy taste and/or odor.
- We constantly work to optimize the use of our available treatment capabilities at the Hennessey Treatment Plant but must continue using water from all three of our sources to meet system demands.
- To alleviate any temporary adverse taste and/or odor, you can chill your tap water, add citrus (lemons, limes, oranges, etc.) or cucumbers, or aerate your water by swirling it in a large pitcher.
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
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 2016 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. Beginning April 1, 2016, all water systems were required to comply with the Federal Revised Total Coliform Rule, monitoring the presence of indicator bacteria naturally present in the environment. Under this rule, the City was required to conduct a Level I assessment, but no problems were found nor corrective actions required. In addition, the City met all of the other stringent State and Federal standards for finished drinking water.
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.