Uni-directional Flushing (UDF)

Uni-directional Flushing (UDF)

Uni-directional Flushing (UDF) is used to improve operations and enhance the water system. Water main flushing is considered an effective method to remove unwanted tastes, odors, or discolorations of the water, and to improve chlorine residual. UDF, a specific type of water main flushing, uses less water than conventional flushing and provides greater cleaning of the pipes.

UDF isolates each pipeline to create flow in a single direction to quickly and efficiently clean the pipe. By concentrating the flow in one direction, UDF creates higher velocities that are better able to clean the pipe.  The major advantages of this method are improved cleaning of accumulated deposits on pipes, less required water than conventional flushing, and an impact reduction for customers


We started the Water Improvement Project in the spring of 2019 as an effort to clear our water mains of sediment and mineral build-up. This will not only extend the life of our water mains, but it will also improve water quality. 

This project includes Unidirectional Flushing, which involves systematically opening hydrants to “flush” mineral deposits from the pipes; and Ice Pigging, which is done by pumping an ice slurry into the main lines and forcing it along inside in order to scour the interior of the pipe and remove sediment.

We encourage you to subscribe to our website and CodeRed (our emergency notification platform). You will automatically receive updates about the project when your area is being affected.

Current Projects - Updated on 9/10/2021

2021 UDF - Where/When 

  • Contractor, HHydrant Flushing Photoydra Tech, completed the unidirectional flushing in Zones 3, 7, and 8 in the spring of 2021
  • Unidirectional flushing will continue in the fall of 2021 as the seasonal water demand declines.

Town-Wide Status

Significant progress has been made since this program began in the fall of 2019. To date, 7 out of the 12 zones in the Town have been unidirectionally flushed. These zones are 1, 2, 3, 5, 6, 7, and 8. Please click on the image below for a map of the flushing zones.

Flushing Program Zone Map
  1. Important Update from the Water & Sewer Division - Sewer System Work will Continue on Thursday, 9/16

    Contractor National Water Main Cleaning Company and subcontractor N&M Excavating are scheduled to continue the sewer system improvement project on Thurs, Sept 16. The list of streets the contractor anticipates working on is included in the full message. Read on...
  2. Important Notice from the Water & Sewer Division - Flow Testing on 9/16

    On Thursday, September 16, 2021, at approximately 9:00AM, distribution system flow testing will be conducted near 940 Boston Turnpike. Residents and businesses in the vicinity may experience reduced pressure or discolored water. Read on...
  3. Important Message from the Water and Sewer Division - Leak Detection Starting on 8/30

    JMR Water Services will be completing leak detection on the Town's water distribution system over the next month, weather permitting. Employees of JMR will walk, ride scooters, and drive vehicles to analyze the water system and report any detected leaks Read on...
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More Information about Hydrant Flushing