Annual Distribution System Flushing Program

Updated May 1, 2025

Our 2025 annual water distribution system flushing has concluded. Our crews successfully flushed 3,563 hydrants.

Each spring, Prince William Water crews flush water mains by opening fire hydrants and allowing them to flow freely for a short period of time. This forcefully draws water through the water pipes to dislodge sediments and minerals that may have collected during the previous year.

In addition, Prince William Water’s drinking water providers, Fairfax Water and the City of Manassas, temporarily change the primary disinfectant in their water treatment process from chloramines to free chlorine. Our water providers indicate that this temporary change facilitates an effective flushing program for the distribution system and is a drinking water industry best practice.

Customers might notice the following during our spring water quality programs:

• Prince William Water personnel and trucks performing system flushing activities in their neighborhoods.
• A slight chlorine smell in their tap water. Customers who are sensitive to chlorine taste or odor may want to fill a pitcher with water and leave it uncovered on the counter, which will allow the odor to dissipate within a couple of hours.
• Brief periods of cloudiness in their tap water. Customers can run the cold-water tap for approximately two minutes to reduce cloudiness.

Read our Frequently Asked Questions about the system flushing program.

Prince William Water will also provide timely updates about its system flushing program on Facebook and X. These updates will specify the areas of the County where crews will be flushing water through hydrants during specific date ranges.

As with chloramines, facilities with chlorine-sensitive processes must continue removing chlorine from water.