DC Water is reducing water quality testing along the Potomac River from daily testing to twice a week as monitoring shows bacteria levels have returned to normal following the January Potomac Interceptor sewer collapse.
The collapse released an estimated 243.5 million gallons of wastewater into the environment and was described by the University of Maryland as one of the largest sewage spills in U.S. history.
Daily testing at the current 10 locations will end Friday, August 7. Weekday testing will continue from August 10 through August 14 before transitioning to Tuesdays and Thursdays from August 18 through September 10.
Testing will continue at six Maryland locations: Old Anglers, Lock 10, the south bank of Minnie’s Island, the north shore of the Potomac River at Minnie’s Island, Sycamore Island and Lock 6. In addition to E. coli testing, Thursday samples will include more detailed testing for oxygen levels, nutrients, metals and other indicators of water quality.
The change comes after Montgomery County recently lifted its remaining shoreline and sediment health advisories, including those around Minnie’s Island, after testing showed bacteria levels in the sediment had returned to acceptable levels. Minnie’s Island has reopened for recreational use.
DC Water said months of testing indicate that long-term impacts from the January sewer overflow are not expected. The utility continues to work with the Maryland Department of the Environment on a final Environmental Rehabilitation Plan.
Long-term repairs to the Potomac Interceptor are also continuing. DC Water is repairing approximately 2,700 feet of pipe and expects to begin installing a new pipe inside the existing sewer line in September.
