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Hillsboro Water Department Pilots Unidirectional Flushing Program in Southeast Hillsboro

Post Date:05/06/2019

Unidirectional FlushingTo continue providing clean and safe drinking water, the City of Hillsboro Water Department will pilot a new Unidirectional Flushing (UDF) Program from May 8 through May 10, in southeast Hillsboro.

Water agencies regularly use unidirectional flushing to scour, clean, and improve the inside of water pipes responsible for delivering high-quality water straight to customers’ taps. 

Over time, small amounts of sediment from mineral deposits and organic matter can settle out of the water and accumulate in the bottom of water pipes. Sediments can discolor drinking water and affect chlorine residual, or the amount of chlorine remaining in the water after its initial application (chlorine kills bacteria in drinking water).

This test round of unidirectional flushing —­ on SE Francis Street south to SE Drake Street, and SE Century Boulevard west to SE Imlay Avenue — is Hillsboro Water Department’s first step in implementing an ongoing flushing program.

When performing unidirectional flushing, Water Department operations crews will: 

  • Open and close pre-determined water valves to isolate a specific section of water pipes
  • Open a specific fire hydrant to draw water through and flush the now-isolated section of water pipe
  • Drain flushed water into the City’s Sanitary Sewer and Stormwater systems once the chlorine has been removed from the flushed water

Flushing typically takes 20 minutes, but depends on the age, type, length, and diameter of the water pipes — and the amount of sediment buildup present. Residents in the immediate vicinity of the flushing may notice temporarily discolored water and lower than normal water pressure. If this does occur, please be aware that the Hillsboro Water Department is diligently working to minimize any inconvenience caused to customers during the flushing process. Residents in the immediate flushing area are asked to avoid running the washing machine or dishwasher until flushing is complete.

Travelers in the area are encouraged to stay alert, drive carefully, and give crews plenty of room as they flush water pipes through hydrants.

Funds from the Hillsboro Water Department’s water rates support the UDF program, as well as other Water Department maintenance programs.

Please call 503-615-6700, email, or visit 150 East Main Street, Third Floor with any questions or concerns about UDF flushing. 

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