Testing will continue through September 10 at six Maryland locations closest to January sewer collapse

DC Water is moving from daily Potomac River water quality testing to testing twice a week. The change is part of our continued response to the January Potomac Interceptor sewer collapse. Daily testing continued past the original July 31 end date and today will be the last day DC Water will test at the 10 current locations.

The twice-weekly schedule will include more detailed testing once a week, continuing through September 10. This testing will check for bacteria and other signs of river health.

Recent tests show bacteria levels in the river have returned to normal, with the usual changes after rain. Last week, Montgomery County also 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 to the public for recreational use.

DC Water continues to coordinate with the Maryland Department of the Environment (MDE) on the final Environmental Rehabilitation Plan. The updated testing schedule is consistent with commitments outlined in DC Water’s July 16 response to MDE.

“We know residents, river users and environmental groups want clear information about the Potomac River,” said Matthew T. Brown, Interim CEO and General Manager of DC Water. “Testing so far shows the river has returned to normal conditions. We will keep monitoring the river, sharing results, and working with MDE as we finalize the recovery plan.”

Testing will continue at the six existing Maryland locations: Old Anglers, Lock 10, South bank of Minnie’s Island, Minnie’s Island north shore of the Potomac River, Sycamore Island, and Lock 6. The transition will start this weekend according to the following schedule:

• No weekend testing - Saturday, August 8 and Sunday, August 9
• Daily Weekday Testing - Monday, August 10 through Friday, August 14
• Twice Weekly Testing – Tuesday, August 18 through Thursday, September 10 every Tuesday and Thursday

In addition to E. coli testing, Thursday samples will measure oxygen levels, and test for nutrients, metals, and other substances that can affect water quality.

DC Water will continue to share water quality sampling data with the public. Results for the expanded testing will be available about one to two weeks after samples are collected on our Potomac Interceptor Response Page.

Based on months of testing since the spill, DC Water does not expect long-term impacts from the sewer overflow in January. DC Water is continuing its testing to answer remaining questions, provide more information during the recreation season, and support the final Environmental Rehabilitation Plan.

Long-term repairs also continue on the affected section of the Potomac Interceptor that collapsed. DC Water is repairing 2,700 feet of pipe, including the area where the collapse happened. Crews are building a temporary pipeline and pumping system to move wastewater safely around the work area. In September, DC Water expects to begin installing a new pipe inside the existing sewer line, creating a stronger pipe inside the old one.

For more information about the repair work and environmental recovery efforts, visit dcwater.com/potomacinterceptor.