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The original item was published from 11/26/2018 3:41:03 PM to 11/27/2018 9:08:03 AM.

News Flash


Posted on: November 26, 2018

[ARCHIVED] Annual Hydrant Flushing Begins Soon

Hydrant Flushing

The City of Napa Water Division will begin our annual Hydrant Flushing Program during the week of December 3. This year’s program is expected to continue through April 2019 and will include Browns Valley, Alta Heights and downtown regions of the City of Napa water service area.

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.  

This program may cause periods of discolored water and reduced water pressure in localized areas where flushing is being conducted. The discoloration of water is due to mobilization of particles and minerals that have settled in the water main by the high velocity water before being 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.

Although customers will continue to have water service during this program, flushing operations may activate low-pressure alarms on automatic fire sprinkler systems due to temporary reductions in water pressure.

Commercial customers, especially businesses that serve the public, should be aware of the water quality while flushing is taking place in their area.  

The hydrant flushing staff will be using dechlorination tablets to remove chlorine in the water before the water goes into the storm drain system and eventually into the Napa River. Due to the high volume of water flowing from the hydrants, the dechlorination tablets may cause some bubbling of the water, giving it a soapy appearance. The tablets are environmentally safe and are being used to protect the river.  

This year’s program will start with Zone 4 (Browns Valley, then Alta Heights), then Zone 1—the central downtown area from Lincoln Ave in the north to the Marina south of Imola Ave. 

Due to the nature of the flushing program, it is difficult to determine the exact day we will flush in a given area. For that reason, the Water Division will update the City’s website regularly to provide a map of the region being flushed each day and a map of the region that will be flushed next, to help keep the public up-to-date on our progress. The flushing program maps and updates can be found at:

The City thanks Napa residents and businesses for their patience and apologizes for any inconvenience our program may cause. Please contact the City of Napa Water Division at (707) 257-9521 with any questions or concerns.

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