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The City of Portland, Oregon

Portland Water Bureau

From forest to faucet, we deliver the best drinking water in the world.

Customer Service: 503-823-7770


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Hydrant Flushing

1 image on the left of an orange hydrant with water spilling out the side onto the street with a sign that says "Flushing Our System to Maintain Water Quality"; an image in the middle of two PWB staff conducting flushing, one is turning a valve attached to a hydrant and one is watching the water flowing out giving a thumbs up; and a 3rd image of an orange hydrant with a red automatic flushing device that looks like a box attached. Water is flowing out of the box onto the concrete and street below.

Hydrant flushing is a technique used across the country to maintain water quality and clean the pipes that deliver water to homes and businesses. In unfiltered water systems, such as Portland’s, sediment and other organic material accumulate at the bottom of the water mains. This material can impact water quality and cause customers to see discolored water at the tap when it is stirred up by construction, firefighting, main breaks, or other activities or events. The Portland Water Bureau uses hydrant flushing to maintain water quality by refreshing water in the mains and to clean the water mains by flushing the material out.

Water used during flushing is doing important work. While it may appear wasteful, the flushing technique the Water Bureau uses is an efficient and necessary use of water to maintain the integrity of the pipes and ensure excellent water quality. Similar to how we brush our teeth every day, cleaning the inside of our water mains on a routine basis is an essential part and a planned investment in maintaining the health of our water system.

Using hydrant flushing, the Portland Water Bureau is currently on track to clean all 2,200 miles of water main before the new filtration plant is online by 2027. This is to help prepare the system for a change in water quality and chemistry once the filtration plant is running. After the filtration plant is online, flushing will be conducted on a continual basis to maintain water quality and the drinking water infrastructure.


Flushing in Your Neighborhood

Where is flushing happening in the City? Find out on WaterWorks.

Flushing will have minimal impacts to customers. If you see flushing crews working in the area, please drive carefully and treat them like any other road construction crew.

Flushing crews usually work Monday through Friday, between 8 a.m. and 4 p.m. There may be circumstances where crews will have to conduct work outside of these hours. 


During Flushing

There may be rare instances when customers notice discolored water or lower water pressure. Customers can report this to the Water Quality Line: 503-823-7525 or

Discolored water is not consistent with the quality of water that the Portland Water Bureau intends to serve to its customers. While discolored water is present, customers may choose to drink bottled water or water from their stored emergency water supplies.

To prevent the discolored water from getting pulled into plumbing throughout the whole house or building, customers should also avoid using tap water or running appliances, such as the washing machine, dishwasher, or ice maker, until flushing is complete.


After Flushing

If you experience some discoloration in your water from nearby flushing, run the water at one tap for 2-3 minutes to see if it clears.  If it does not clear wait an hour and try again.  When the water runs clear, flush any taps where discolored water was present.


Need Assistance?

The Water Quality Line is available 8:30 am – 4:30 pm Monday-Friday at 503-823-7525 or If you have a discolored water-related emergency after these hours, please call 503-823-4874 option 1 to speak with a Water Bureau Emergency Dispatcher. To learn more about home water quality, visit the Water Bureau’s Drinking Water Quality at Home page.