Authorities in Washington, D.C., and Arlington, Va., advised all 920,000 residents on Wednesday to boil their drinking water after algae blooms in the Potomac River raised pollution levels in a reservoir.
The boil water advisory, which includes the Pentagon, Arlington National Cemetery, and Reagan National Airport, will remain in effect until it is confirmed safe to drink, according to the District of Columbia Water and Sewer Authority.
John Lisle, a spokesman for the Washington water utility, noted that it is unusual for a boil water advisory to cover the entire city, adding that he had not seen such a broad warning in his 11 years with the utility.
Arlington County warned that cloudy or hazy water could indicate lower water quality, potentially containing bacteria, viruses, and parasites that cause nausea, cramps, diarrhea, and headaches. Infants, children, older people, and those with compromised immune systems are particularly vulnerable.
Authorities advised discarding any drinks or ice made after 9 p.m. on Wednesday. Residents should bring water to a rolling boil for at least one minute and let it cool before using it for drinking, brushing teeth, washing food, preparing baby food, making ice, or giving to pets.
Following the detection of increased algae and turbidity, the U.S. Army Corps of Engineers, which operates the Washington Aqueduct, increased its filtering capacity by cleaning existing filters and purchasing additional ones.
The Washington Water Authority reported that turbidity was found at the Dalecarlia Water Treatment Plant. Initially, the Washington Aqueduct shifted all water treatment to the McMillan plant, but concerns over water supply, particularly for fire emergencies, prompted officials to resume pumping from Dalecarlia.
Lisle mentioned that the decision to use water from the Dalecarlia plant was also influenced by the expected increase in water use during the Fourth of July holiday. The timeline for lifting the advisory remains unclear.
Fairfax Water, a utility serving another Northern Virginia suburb, stated that no boil water notices were issued in their area because they had stopped receiving water from the Washington Aqueduct earlier on Wednesday.
