Water Main Flushing

The City of Gig Harbor regularly flushes the pipes in our water system to remove rust and sediment and provide you with clean, reliable water.

Water Main Flushing Quick Facts

• Flushing forces water to move through the lines and out through fire hydrants. This also helps us find and repair malfunctioning valves and hydrants before they cause problems.
• During flushing, you might see utility crews working at hydrants and valves in intersections and at the end of cul-de-sacs. They are trying to create high-velocity flows in the system to scour the inside of water mains.
• Your water pressure may decrease during flushing.
• Rust and sediments stirred up during flushing could temporarily discolor your water.
• If you do get discolored water or find sediment in your water, run the cold water for a few minutes - the bathtub faucet works best.
• Your first load of laundry after flushing should be dark clothes.

How Flushing Works

The city 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.

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. It is not uncommon to experience discolored water during this process.

What to Expect

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.