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Water Main Flushing

Tacoma Water performs two types of flushing operations: systematic flushing (also known as unidirectional flushing) and dead-end flushing. Both are very important to ensuring clean, safe and reliable water is delivered to our customers.

Both systematic and dead end flushing complement our existing water testing and preventive maintenance programs. The benefits and impacts of water main flushing are water quality and reliability.

Flushing forces water to move through water lines and out through fire hydrants, removing rust and sediments that can collect in the water system.

While flushing, we can easily find and repair malfunctioning valves or other water system components before they cause problems. Additionally, data is collected during the flushing process to confirm the condition of the water and capacity to meet fire flow requirements.


How Flushing Works

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. These higher velocities allow sediments and corrosion products to be lifted from the bottom of the water main and discharged out of the fire hydrant, helping to ensure clean, safe and reliable water for our customers.

Dead-End Flushing
During the dead end flushing process, we flush water from a fire hydrant or a dead-end blow-off connection. The primary intent is to “freshen up” the water in dead-end portions of the system where water - while still safe - can become stale. Most customers will not experience any adverse effects from dead-end flushing operations.

What to Expect
A few weeks before systematic flushing begins in your neighborhood, we will mail a notice to all affected customers. 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.

It is possible that the sediments stirred up during flushing will discolor the water. You can easily keep this water out of your home or business by not using water while flushing is underway. That includes not running appliances that use water, such as clothes washers and dishwashers.

Any discolored water that gets into your home or business water lines is temporary, not harmful and should clear up quickly. If you experience discoloration or sediment in your water following flushing, remove aerators from your faucets and run cold water for a few minutes. We also recommend that your first load of laundry after flushing be dark clothes.



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