Water Line Flushing

Unidirectional Flushing (UDF) Program

Project Overview

The City of Kennewick Public Works Department will be conducting a Unidirectional Flushing (UDF) program on the City’s water system. The UDF program will help to ensure that water customers continue receiving high-quality drinking water.

What is Unidirectional Flushing (UDF)

Unidirectional flushing, or UDF, is a relatively new method of routine maintenance that consists of flushing the City’s water mains at specific zones. Flushing the system at increased velocities cleans the water pipe’s inner walls and removes a variety of naturally accumulated sediment.

Benefits of Unidirectional Flushing

While flushing by the City in the past has been effective in maintaining water quality, UDF has been refined over the course of many years and provides a variety of benefits. Most importantly, the process ensures the City’s residents will continue receiving high quality potable water. In addition to producing high quality water, UDF uses less water than the old flushing methods. This means lower costs by reducing staff hours, vehicle use, fuel and wasted water supplies.

What to Expect During the Program

The pilot program is anticipated to begin in April 2018 and will be performed by City of Kennewick Public Works personnel. Flushing activities will be coordinated and communicated in advance via news media outlets.  The hours for which flushing will occur will vary depending on location.

  • UDF involves closing specific valves followed by opening fire hydrants under controlled conditions to clean the inner surface of water pipes.
  • Every effort will be taken to minimize water service disruption during the process. In some cases, however, customers may experience a temporary drop in water pressure and/or discolored water. The discolored water does not pose a health hazard. If the discolored water does not clear up after running your tap for a few minutes (minimum of 10 minutes), please call the phone number provided below.
  • Maintaining access and water services to homes and businesses will be a top priority.
  • You may see valve and fire hydrant maintenance equipment in your area.


  • Safety of personnel
  • Improve water quality.
  • Increase water distribution system performance.
  • Reduce chlorination needs
  • Address public concerns.
  • Minimize inconvenience during the project.

If you have questions or comments, please contact us Monday - Friday, between 7:00am and 3:30pm, at (509) 585-4419, or use the email form in the "Contact Us" section.