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Water Flushing Program

The Department of Utilities recently started a program to maintain high quality drinking water by “flushing” water pipes to restore fresh water and remove sediment and deposits from the City’s water distribution system.

City staff flush pipes by releasing water from fire hydrants to:

  • Remove sediment and unwanted minerals from the water distribution system
  • Replace old water with fresh water
  • Remove organic matter that can build up over time inside pipes

The City uses a method of flushing where the water origin, direction, and speed of flow is carefully engineered to ensure proper cleaning of the pipe.

This process helps reduce taste and odor issues, and helps maintain valves and hydrants.


Why is flushing important?

Most of the City’s drinking water comes from the Sacramento and American rivers.

Although drinking water is fully treated, sediment and other deposits slowly build up inside the water pipes over time.

Flushing helps remove deposits and will help improve the taste, odor, and color of drinking water.

It also reduces biofilm, which is a thin layer of microorganisms that can grow on the inside of the pipes.

Flushing also helps to identify broken or inoperable valves and hydrants, which is important to ensure they work properly in an emergency.

What does flushing look like?

Flushing requires the opening and closing of hydrants and valves to ensure that water moves through pipe segments for effective cleaning.

Customers may notice water coming out of fire hydrants for several minutes while City staff flush them.

Often, a Utilities vehicle will be nearby. Drivers should use caution when crews are in the area or you see water in the road.

Is flushing a waste of water?

No. Flushing is part of overall maintenance of a distribution water system to maintain high quality drinking water, improve capacity of pipes, and ensure hydrants and valves work properly.

Will I notice water changes to my drinking water?

Some people may notice temporary discolorations or taste and odor changes during and up to a day following flushing.

You should not see any changes to your water supplies, including changes to water pressure.

Can I use my water during flushing?

Customers may avoid running appliances, like washing machines, until flushing is completed in your neighborhood.

This will prevent discolored water from entering a household. If you notice discolored water, run cold water from one faucet for two to three minutes to see if it clears.

If it does not clear, wait an hour and try again. 


Questions can be emailed to If you experience issues during a flushing event, please contact 3-1-1