Temporary disinfectant change in drinking water

March 31, 2008

Washington — For approximately one month, from April 7, 2008 through May 12, 2008, citizens in the District of Columbia, Arlington County, Va., and Falls Church City, Va., (including portions of Fairfax County served by Falls Church City) may notice a slight difference in taste and smell in their drinking water. That taste is chlorine. During this period, there will be a temporary change in the chemistry of the disinfectant added to drinking water at the water treatment plants. The disinfectant kills bacteria in the water and helps keep the pipes in the distribution system clean.

The temporary change in water chemistry will not affect the safety of water for drinking.

The Washington Aqueduct, a division of the U.S. Army Corps of Engineers, is the organization responsible for treating the water. The Aqueduct will temporarily switch the disinfectant it uses in the distribution system pipelines from chloramine to chlorine. This temporary change is part of the regular process used to keep water mains clean and free of potentially harmful bacteria throughout the year. This periodic, scheduled change in disinfectant is a standard water treatment practice. As always, the drinking water will be regularly monitored to ensure that the water delivered meets or is better than federal Safe Drinking Water Act standards.

People and businesses that normally take special precautions to remove chloramine from tap water, such as dialysis centers, medical facilities and aquatic pet owners, should continue to take the same precautions during the temporary switch from chloramine to free chlorine. Most methods for removing chloramine from tap water are effective in removing chlorine.

Disinfection Byproducts: The short-term use of chlorine in the distribution system will temporarily increase disinfection byproducts. Disinfection byproducts are unwanted chemicals, suspected of causing cancer and other health effects that are formed when chlorine reacts with natural material found in rivers and other water supplies. So that long-term exposure to disinfection byproducts can be reduced, chlorine disinfection in the distribution system is not used all the time (and chloramine is used most of the time). It is important to note that the temporary switch in disinfectant from chloramine to chlorine will not affect the safety of the water for drinking. The water will continue to meet federal health standards. Early concerns that there might be a link between disinfection byproducts and miscarriages have not been confirmed by scientific studies. However, women who are concerned may wish to use an alternate source for drinking water during this period.

If your water has a noticeable chlorine taste during this period, you may be able to reduce the taste by refrigerating a pitcher of drinking water overnight. Some customers may notice a slight change in water color. This discoloration should also be temporary. Simply run the cold water from your faucet until the water is clear. In the unlikely event that your water remains discolored and cloudy, we encourage you to contact your local water authority at the numbers listed below:

DC WASA: 202-612-3440 (Monday-Friday, 8:00 a.m. – 4:30 p.m.) or 202-612-3400 (24-hour)

Arlington County: 703-228-6570 (Monday-Friday, 8:00 a.m. – 5:00 p.m.) or 703-228-6555 (24-hour)

Falls Church City: 703-248-5071 (Monday-Friday, 8:30 a.m. – 5:00 p.m.) or 703-248-5044 (24-hour)

www.dcwasa.com
www.arlingtonva.us
www.fallschurchva.gov
http://washingtonaqueduct.nab.usace.army.mil/

Latest News

View of Mary at bottom of shaft inside tunnel shown from above

First turn of cutterhead signals the start of excavation for the Potomac River Tunnel Project

In a defining moment for one of the District’s largest infrastructure investments, DC Water has marked its next major milestone in the Potomac River Tunnel Project. The first tunnel boring machine, Mary, has launched her northbound journey breaking through the soil to signal the start of excavation.

With the first turn of Mary’s drill-like cutterhead underground, the machine pushed forward to begin tunneling, representing the transition from years of planning and preparation to active tunnel construction on the $819 million project.

Photo of the vegetation growing back in the culvert area
  • DC Water has completed soil removal, utilizing excavators and manual digging, to expose the clay lining for the C & O Canal between locks 13 and 14. This is the final step in the clean-up process ...
Workers manually removing soil between the locks

Work is progressing on the clean-up for the C & O Canal which was used as a bypass while the Potomac Interceptor was repaired. Workers are focused on removing sludge between locks 11 and 12. Soil removal is also nearly complete between locks 12 and 14, reaching the canal's clay liner. Workers are now manually removing additional materials in some areas.

Upcoming Meeting

Board of Directors Meeting

April 24, 2023

Monday 9:00 AM

Announcement

View of Mary at bottom of shaft inside tunnel shown from above
DC Water Launches Tunnel Boring Machine Mary, Marking Important Step for Potomac River Tunnel Project

First turn of cutterhead signals the start of excavation for the Potomac River Tunnel Project

In a defining moment for one of the District’s largest infrastructure investments, DC Water has marked its next major milestone in the Potomac River Tunnel Project. The first tunnel boring machine, Mary, has launched her northbound journey breaking through the soil to signal the start of excavation.

With the first turn of Mary’s drill-like cutterhead underground, the machine pushed forward to begin tunneling, representing the transition from years of planning and preparation to active tunnel construction on the $819 million project.

Latest Blog Post
A helicopter lowers a drill rig to workers on the Potomac River.
DC Water begins drilling in Potomac River to explore options to rehab underwater sewer line
When one of your major sewer lines runs through the Potomac River, a backhoe and trencher won't do. That's why we've got helicopters carrying a 14-ton drill and workers suspended midair over the Potomac.
Upcoming Meeting
Date
April 15, 2026
Wednesday, 9:30 AM

Customer Service Center Announcement

Payment Plan Incentive: provides a credit back of 50% of the last 3 payments made. Eligible participants are residential customers who have had an outstanding balance for 60 days or greater and with an outstanding balance of $500 or more.