Flushing hydrant
March 16, 2016

Loudoun Water and other utilities around the country begin hydrant flushing every spring as a way to clean their water distribution systems. Hydrant flushing has several benefits including:

  • Clearing sediment from the lines
  • Giving crews a chance to monitor our system
  • Ensuring high standards of water quality

Flushing in the Loudoun Water service area will begin the week of March 28 and will continue for about 12 weeks. The flushing of hydrants around the service area will have no effect on water usage.

There are over 11,000 hydrants in the Loudoun Water system that must be maintained by our Field Service team. At each stop, a team member will open a hydrant and take samples to measure water quality. Each day, they will typically flush around 25 hydrants per person in addition to their usual responsibilities.

To see when crews will be in your area, follow us on Twitter @loudounwater or check back frequently to see our hydrant flushing map.

Frequently Asked Questions:
What’s that taste?
During Spring flushing, some customers may notice a more pronounced chlorine taste or odor in the water. Fairfax Water (our wholesale water provider) temporarily switch from chloramines to free chlorine during each spring. Loudoun Water also  switches from chloramines to free chlorine during each spring.  Free chlorine serves as an aggressive disinfectant that aids in the disinfection of the flushed water mains. Filling a pitcher with water and placing it in the refrigerator will help to alleviate the chlorine taste. After springtime flushing is complete, Fairfax Water and Loudoun Water will switch the disinfectant back to chloramines. This is standard practice for many water utility systems throughout the United States.

Why does water have a ‘milky’ or ‘bubbly’ appearance during flushing?
This is simply a result of the oxygen in the water being stirred up during flushing causing visible air bubbles. Letting the water sit in a glass for a few seconds will take care of the air bubbles! With this phenomenon you will see the bubbles clear from bottom to top.

Why is my water discolored?
Flushing may result in temporary discoloration and the presence of sediment in your water. These conditions are not harmful and should be of very short duration. If noticed, avoid doing laundry during this time (while crews are on your street) to avoid discoloration. If water remains discolored or cloudy for an extended timeframe contact Loudoun Water Customer Relations at 571-291-7880.

Will my water pressure be affected?
Some customers may notice a slight pressure fluctuation when our crews are working on their street. Pressures will return to normal once the flushing has finished.

Are my fish safe during the disinfectant switch?
You will need to treat tap water before using it in a fish aquarium. Disinfectants can harm fish. Check with a local pet store to learn what types of chemicals you need to add to the tank to neutralize the effects of the disinfectant.

Why isn't the water captured or reused?
There are a lot of variables that make the process of capturing, collecting and transporting the water difficult. The amount of pressure released when hydrants are flushed makes it very difficult to recapture.

Who pays for this water?
The cost of hydrant flushing is build into the normal cost of operations.