Water Main Flushing

Tacoma Water regularly flushes the pipes in our water system to remove rust and sediment, which helps ensure you receive clean, reliable water. Flushing forces high-velocity flows through the pipes and out through fire hydrants. Along with scouring the inside of water mains, this also helps us find and repair malfunctioning valves and hydrants before they cause problems.

Water main flushing events are shown in two locations: 

  1. Water Flushing Map – Tracks flushing crew progress as they work to maintain water quality.
  2. Water Event Map – Displays only active work that is scheduled or in progress. 

What to Expect During Flushing
  • A few weeks before systematic flushing begins in your neighborhood, we will mail a notice to alert you.
  • Several days in advance of flushing, crews will place high visibility signs at major intersections leading into your neighborhood as well as in the immediate flushing area. Crews will relocate these signs each day as work progresses.
  • During flushing, you might see utility crews working at hydrants and valves in intersections and at the end of cul-de-sacs.
  • Your water pressure may decrease during flushing.
  • Rust and sediment stirred up during flushing will likely discolor your water. This is temporary, not harmful and should clear up quickly.
  • Try to not run the tap or turn on appliances that use water, such as dishwashers and clothes washers, when flushing is going on in your area.
  • If you do get discolored water or find sediment in your water, remove any aerators from your faucets and run the cold tap for a few minutes.
  • Make sure your first load of laundry after flushing is dark clothes only.

If you have questions during normal business hours about our flushing programs, or if your water does not clear up within a short time after flushing is completed, please contact our Water Quality Section at (253) 502-8207 or waterquality@cityoftacoma.org.

After business hours, call the Water Emergency Control Center at (253) 502-8344.

How Flushing Works

We perform two types of flushing operations: systematic flushing (also known as unidirectional flushing) and dead-end flushing. Both are critical to ensuring you receive clean, safe and reliable water service. Flushing also complements our existing water testing and preventive maintenance programs.

Additionally, data is collected during the flushing process to confirm the condition of the water and capacity to meet fire flow requirements.

Systematic Flushing

During the systematic flushing process, crews will be opening and closing street isolation valves, working at fire hydrants, in street intersections and at the end of cul-de-sacs. Crews will isolate sections of the water system and open fire hydrants and blow-offs to create high velocity flows in the water mains to remove sediment and corrosion from the bottom of the water main.

Dead-End Flushing

During the dead-end flushing process, we flush water from a fire hydrant or a dead-end blow-off connection. The aim is to refresh the water in less-used portions of the system where water, while still safe, can become stale. You are unlikely to experience any adverse effects from dead-end flushing operations.