Washington Aqueduct recommends lift of Boil Water Advisory for District of Columbia and parts of Northern VA

USACE, Baltimore District
Published July 4, 2024

The Washington Aqueduct recommends lifting the Boil Water Advisory issued Jul. 3, 2024, for the District of Columbia and portions of Northern Virginia after water levels return to normal ranges.

Out of an abundance of caution and water supply concerns for the 4th of July holiday, the Washington Aqueduct originally recommended issuing the Boil Water Advisory as a precautionary measure to protect public health in response to an increase in algae and resulting turbidity.

Algae blooms generally occur during high temperatures, causing conditions in water where nutrient levels are high. Turbidity, a measure of water’s cloudiness or clarity, plays a crucial role in assessing water quality. It is an important factor in water quality, as it can interfere with the effectiveness of water treatment process and impact the color, taste, and smell of drinking water.

After determining the water replenishing process was successful with levels within normal ranges, and no threat to public health, the Washington Aqueduct recommended lifting the boil water advisory.

Washington Aqueduct staff worked throughout the night to ensure water supply met U.S. EPA established water quality standards. Staff closely monitored water levels, implemented additional mechanical and chemical treatment solutions, washed filters to increase production, made necessary chemical adjustments, and brought alternate filters online for additional treatment capacity. Additionally, the EPA authorized the addition of copper sulfate and sodium permanganate to combat algae in the Washington Aqueduct’s reservoirs.

The Washington Aqueduct never deviated from U.S. EPA established water quality standards and continues to take proactive measures to protect public health.

The Washington Aqueduct will continue to closely monitor water levels and coordinate with its wholesale customers, EPA, and local and state agencies. Updates will be available via the Washington Aqueduct’s website: http://www.nab.usace.army.mil/Missions/Washington-Aqueduct/

The Washington Aqueduct collects, purifies, and pumps an average of 150 million gallons of water per day at two treatment plants in the District of Columbia for its three wholesale customers - DC Water, Arlington County, and Fairfax Water. We encourage water users to visit their respective water provider’s website for additional information, including recommendations on how they can reduce the impact to water supply as this issue evolves.  


Additional Information

Baltimore District delivers vital engineering solutions in collaboration with its partners to serve and strengthen the Nation, energize the economy, and reduce disaster risks. Headquartered near Baltimore’s Inner Harbor, Baltimore District provides design, engineering, construction, environmental, and real estate expertise to various important projects and customers. This support spans five states, the District of Columbia, overseas, and the Susquehanna, Potomac, and Chesapeake Bay watersheds. These civil and military missions and diverse engineering services support communities and warfighters while addressing the ever-growing list of emerging national security requirements and ultimately protecting the Nation.


USACE Baltimore

Release no. 24-014