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8570 Executive Park Avenue
    Fairfax, VA 22031
Main: 703-698-5600
    Customer Service: 703-698-5800
After Hours / Emergencies: 703-698-5613
    TTY: 711

Winter Water Tips



Annual Water Main Flushing

service area map

2017 Water Main Flushing Program

Each spring, Fairfax Water flushes its water mains by opening fire hydrants and allowing them to flow freely for a short period of time. We do this to maintain the high water quality in our distribution system. You will likely notice Fairfax Water personnel in your neighborhood operating hydrants from late March through June.

During this time, our treatment process switches from using combined chlorine to free chlorine. This will start on March 20 and end on April 17 for customers who receive water from Washington Aqueduct (areas in green and red on the map). For the remainder of the system, this will begin March 27 and last through June 19 (areas in blue on the map).


You will be able to recognize our employees by a number of identifiers:

  • Our employees will be driving vehicles identified with the Fairfax Water logo.
  • Our employees will be displaying a sign that identifies the employee as part of the Fairfax Water flushing program.
  • Our employees will be wearing uniforms with the same Fairfax Water logo.

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 you have questions about this program or the work being conducted in your area, you may call our dispatch operator any time of the day or night at 703-698-5613, TTY 711.

Temporary Change to Free Chlorine

hydrant During this flushing period, a slight change is made in the water treatment process to facilitate an effective flushing program. Throughout the year, chloramines, also known as combined chlorine, is added to the water as the primary disinfectant. During the spring flushing program, chlorine is added in an uncombined state, commonly referred to as free chlorine. Free chlorine is quicker acting than combined, which allows it to react with sediments suspended during flushing.

Depending on your usage patterns and location within the distribution system, it could take up to a week for your drinking water to transition from combined to free chlorine at the beginning of the flushing program, or from free chlorine to combined chlorine at the conclusion of the flushing program.

You may notice a chlorine taste and odor in your drinking water while free chlorine is utilized. If you are especially sensitive to the taste and odor of chlorine, try keeping an open container of drinking water in your refrigerator. This will enable the chlorine to dissipate, thus reducing the chlorine taste. Remember drinking water has a shelf life! Change out the water in your refrigerated container weekly.

Please note: If you have an aquarium or pond, always test the water you add to your aquatic environment to be sure it is free of chlorine before adding fish or other animals. Chemical additives with directions for removing either free chlorine or chloramines from water for use in fish tanks or ponds are available at pet/fish supply stores. See our Water Quality FAQ page for additional information.