The District of Columbia Water and Sewer Authority (DC Water) issued a boil water advisory for parts of Northwest and Northeast Washington, D.C. on Jan. 19 due to an unexpected loss in water pressure.
The advisory was a precautionary notice to residents in Wards 3, 4 and part of Ward 5 to filter and then boil water that may be consumed because of uncertain water quality in this area of the system.
The notice also advised residents to dispose of any drinks and ice produced after 11 a.m. on Friday, Jan. 19, 2024, to run cold water until it clears before boiling, to run cold water for 2 minutes before boiling if there are known sources of lead and to store the cooled water in a sanitary, covered container.
The loss of pressure could have caused backpressure, or “a net movement of water from outside the pipe to the inside through cracks, breaks, or joints in the distribution system that are common in all water systems,” according to DC Water.
This backpressure could have led to fecal contamination or other disease-causing bacteria entering the water distribution system.
When the water distribution system falls below 20 psi, U.S. Environmental Protection Agency (EPA) regulations require DC Water to issue a precautionary Boil Water Advisory due to the possibility of contamination.
After receiving more than 1,000 reports to the emergency call center of low or no water pressure from customers in the impacted area, DC Water water and pumping operations crews investigated the distribution system, but could not find any significant leaks or potential causes.
After further investigation, DC Water determined that the loss of pressure was caused by the Washington Aqueduct operating a valve on a bypass service line.
DC Water purchases treated drinking water from the Aqueduct and distributes it to all District residents through 1,300 miles of pipes.
The Aqueduct reopened the bypass valve on Saturday, Jan. 20, resolving the pressure issue.
“The operation of the bypass service valve, as well as the resulting pressure loss and Boil Water Advisory had a significant impact on our customers, local businesses and our critical infrastructure,” said DC Water CEO and General Manager David Gadis.
“It was not the outcome that the Aqueduct or DC Water anticipated – actuating a bypass valve should not have had a detrimental impact on the system – and we will continue to work with the Aqueduct to investigate exactly why that occurred and to ensure it doesn’t happen again.”
The advisory was lifted on Sunday, Jan. 21 after DC Water collected and tested several rounds of water samples from the impacted areas and found no evidence of water contamination.