Washington — For approximately one month, from April 6, 2009 through May 4, 2009, 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 and odor is chlorine. During this one-month period, there will be a temporary change in 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. As always, people with special health concerns should consult their health care provider on the use of tap water.

The Washington Aqueduct is the organization responsible for treating the water. Washington 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)