When we need to clean inside the city’s pipes, we flush water through hydrants. It’s one way we maintain excellent water quality.
About hydrant flushing
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 discolored water at the tap if it is stirred up. (Events that could stir up that material include construction, firefighting, and main breaks.) When we flush hydrants, we flush the material out and bring fresh water into the mains.
Water used during flushing is doing important work. While it may look wasteful, the flushing technique the we use 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, the Water Bureau cleans the inside of our water mains on a routine basis. It’s an essential part of, and a planned investment in, maintaining the health of our water system.
Using hydrant flushing, we are currently on track to clean the city’s 2,200 miles of water mains before the new water filtration plant is online in 2027. We want to flush all the mains before then 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, we’ll keep flushing on a continual basis to maintain water quality and drinking water infrastructure.
Our flushing team uses three types of flushing to clean the water main or maintain water quality in an area: autoflushing, spot flushing, and unidirectional flushing.
Flushing in your neighborhood
Flushing usually doesn’t affect Portlanders as they’re going about their day. If you see flushing crews working in your area, please drive carefully and treat them like any other road construction crew.
Flushing crews usually work Monday through Friday, between 8:00 am and 4:00 pm. Every once in a while, circumstances call for crews to work outside these hours.
If there is an autoflusher installed in your neighborhood, they typically run during the night. If you see an autoflusher running during the day, report it by calling 503-823-7525. If you leave a message, please include the intersection where the hydrant and autoflusher are located.
Discolored water is not consistent with the quality of water we intend to serve. If you have discolored water, you may choose to drink bottled water or water from your emergency supplies.
If you have discolored water, you can avoid pulling that water into your whole house’s plumbing. Avoid using tap water or running your washing machine, dishwasher, or ice maker until flushing is complete.
If you have discoloration in your water from nearby flushing, run the water at one tap for two to three minutes to see if it clears. If it does not clear, wait an hour and try again. When the water runs clear, run the water at any taps where you had discolored water.
Questions about flushing or want to report discolored water or low pressure? You can report these to the Water Quality Line.