Water Line Flushing

As part of Skagit PUD’s ongoing maintenance and water quality efforts, the PUD conducts a water line flushing program throughout its 650-mile water system. Flushing is a process that rapidly removes sediment from the PUD’s water piping system, similar to the process of flushing a car’s radiator.

Flushing -Crew


Flushing uses water force to scour out materials that accumulate in pipes. Water pipes are usually flushed by opening fire hydrants, where the discharged water flows off the streets the same as rainwater. The water flow is measured, and the chlorine in the water is neutralized.

Imagine driving down the road at less than 1½ miles per hour. That’s about the rate that water moves through underground pipes. This slow movement causes sediment, such as rust and mineral particles, to build up over time and accumulate along the pipe’s bottom. A buildup of harmless microorganisms can also coat the pipe’s inner surface. If left unchecked, the materials can restrict water flow in the pipes and contribute to the pipe corroding.

Rapid water pressure changes, such as water main breaks and the use of fire hydrants, can stir up the sediment and dislodge deposits lining the pipe, resulting in a “dirty water” appearance.

Periodically flushing water pipes removes the material buildup, maintains infrastructure, and assures consistent, good quality water.


Although it may appear to waste water, this process is part of routine maintenance necessary to maintain the water system's integrity and continue to deliver the highest quality water possible to our customers.

Skagit PUD is committed to water use efficiency and good resource management practices. The flushing program is monitored to ensure that the least amount of water is used. The PUD continually analyzes system-wide performance standards to minimize water use, including on-going efforts to identify and repair leaks.

How Will This Affect Me?

In advance of crews being in your area, Skagit PUD will alert customers by placing high-visibility signboards throughout your neighborhood.

Residential flushing is generally conducted between 9 a.m. and 1 p.m., Monday through Friday. For businesses and medical services, crews will attempt to coordinate times to ensure the least degree of impact.

Customers may notice low water pressure, discolored water, or no water for short periods of time when flushing is taking place. We recommend customers limit their water use. You should avoid using hot water to prevent sediment accumulation in your hot water tank.

Water discoloration primarily consists of harmless silt and precipitates, which do not affect the water's safety. However, we strongly recommend not washing a laundry load, especially white items, to prevent potential staining.

If you experience discoloration in your water after crews have been flushing, clear the pipes in your own home by running all water faucets on cold, starting with faucets outside first, for a minute or two. 

For flushing questions, call Distribution Superintendent Ryan Anderson at (360) 840-7709.