Hydrant Flushing

UPDATED January 11, 2023

Annual Flushing Program

Hydrant FlushingThe City of Napa Water Division has completed our annual Hydrant Flushing Program for 2022-23. Stay tuned for updates on the 2023-24 program. 

Hydrant flushing is an important maintenance activity to clean and flush the City water mains. Fire hydrants are opened to move a large volume of water at a higher-than-normal velocity through the mains. This procedure mobilizes particles and minerals that have settled over time and flushes them out of the system. This activity assists the City in maintaining the highest quality of water in the public water system.

Current Flushing Area



Next Flushing Area



The flushing program may cause periods of discolored water and reduced water pressure in localized areas where flushing is being conducted. The discoloration is due to particles and minerals that have settled in the main being mobilized by the high velocity water before they are discharged through the fire hydrants. The water will remain safe to use and generally clears within a few hours after flushing has been completed. Residents should monitor their water prior to starting laundry, especially when washing white clothes.

Commercial customers, especially businesses that serve the public, should be aware of the water quality while flushing is taking place in their area. Due to the nature of the program, it is difficult to determine the exact day an area will be flushed; however, on average, each flushing set takes 1 to 3 days to complete, depending on the quantity of water mains to be flushed and the number of valves that are operated.

The City thanks Napa residents and businesses for their patience and apologizes for any inconvenience our program may cause. Please contact City of Napa Water at (707) 257-9521 with any questions or concerns, or consult our Frequently Asked Questions (FAQs) below: