Spring Cleaning for Drinking Water Network Starts Earlier This Year

Published on February 15, 2023

Update 5/18: New date for conclusion of the disinfectant swap is May 21 rather than May 15 due to continued reservoir rehabilitation project work.

Update 2/15: A miscalculated reference in the last sentence to total annual water consumption has been replaced by a more recent statistic. 

Arlington County, along with the District of Columbia and northeastern Fairfax County, will modify the water treatment process beginning Feb. 20, 2023, in an annual practice lasting through May 21. The safeguard involves the industry-standard practice of temporarily swapping the system disinfectant from chloramine, used most of the year, to chlorine. This practice ensures that the water mains remain clean and clear.

Although traditionally begun in March, this year’s early start will allow the Washington Aqueduct to complete a reservoir rehabilitation project. The Aqueduct, operated by the U.S. Army Corps of Engineers, supplies the three jurisdictions with drinking water and initiates the cleaning process for pipes down the line. The Arlington network is made up of some 500 miles of pipes linked to homes, businesses and schools.

Purification systems and constant monitoring by Arlington staff ensures the County’s water is safe and essentially unchanged, although users may notice a slight difference in smell and taste. The switchover will not involve any interruption in service to customers.

Concurrent with the disinfection switch, Arlington will conduct a system-wide flushing to enhance year-round water quality. Residents may see some of the County’s 3,700 fire hydrants flowing at the curb as part of the procedure. 

What to expect Feb. 20 through May 21: 

• Customers who experience a chlorine smell or taste from the tap can run the cold-water line for about two minutes before using water from the tap; employ a filter system; or let the water sit in a container for an hour or two as the chlorine smell and taste dissipate.
• Customers who take special precautions to remove chloramine from tap water during the rest of the year should continue such methods during the temporary switch to chlorine. As always, those with special concerns should consult their health care provider.

Arlington’s drinking water continues to meet or exceed all safety standards established by the federal Environmental Protection Agency and Virginia Department of Health.

The County used approximately 7.7 billion gallons of tap water in Fiscal Year 2022, all originating from the Potomac River.