What is 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 graphic below shows how the water flows through an isolated pipeline in a single direction, by closing valves and using a specific hydrant. In the example below, you'll see that 10 gates have to be closed and two gates have to be opened to direct clean water to the hydrant that is being flushed on Stefaniak Avenue. 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.
The UDF program certainly has its benefits, however one drawback is that it makes it incredibly difficult for both the field crew and office staff to say with any certainty when a specific street or address will be completed. The town is divided into six zone and each zone has between 35 and 104 sequences that require various amounts of time to complete (391 total sequences). In the example below Everett Avenue, located about 700 feet east of Stefaniak Avenue, is 34 sequences and roughly eight work hours after Sefaniak Avenue is flushed. It may appear close from your house, but a lot of work is needed to ensure the clear water is being flushed toward your location.
The Department makes it a point to have clear water flowing to all areas by the end of each workday and that is why we ask that you contact us when you experience discolored water. If you are outside the current flushing zone we typically can get to your area quickly. However, if you are within the active flushing zone it may take a few hours for us to get to you because either a valve needs to be opened or we will be flushing your pipe later that day. As always, your patience during this vital program is greatly appreciated.