Water Line Flushing

City of Pasco Unidirectional Flushing (UDF) Program

Project Overview

The City of Pasco Public Works Department will be conducting a Unidirectional Flushing (UDF) program on the City of Pasco water system. The UDF program will help to ensure the City's 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 a high velocity cleanses the water pipe's inner walls and removes a variety of naturally occurring debris and 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 October 2015 and will be performed by City of Pasco Public Works personnel. Daily flushing is planned from Monday through Friday (no weekends or holidays) between the hours of 8:00am and 3:00pm.
  • UDF involves opening fire hydrants and closing valves 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 or creates staining on your porcelain or laundry, 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.
  • Door hangers with additional information may be distributed as the program progresses through the potable water service area.


  • Focus on safety during the project
  • Improve water quality.
  • Increase water distribution system performance.
  • 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) 545-3463, or use the email form in the "Contact Us" section.