Environmental Restoration Plan
DC Water has begun the rehabilitation and environmental restoration to address areas affected by the sewer overflow from a section of the Potomac Interceptor that collapsed January 19. Contaminated material is being hauled away and work is underway to clear trees, brush, and contaminated debris in and around the collapse site as part of the environmental restoration plan approved by the National Park Service (NPS).
On February 28, NPS issued a Special Use Permit for the repair, rehabilitation, and environmental restoration of the Potomac Interceptor and the C&O Canal National Historical Park at the area of the Potomac Interceptor collapse between Locks 10 and 14.
DC Water continues to evaluate the environmental impacts of the overflow and is exploring further restoration efforts based on input from concerned residents and community groups, along with the ongoing collaboration with federal, state, and local regulators overseeing the environmental restoration.
Background
- Collapse of 72" diameter section of pipe caused overflow of more than 200 million gallons of wastewater into Potomac River.
- Bypass system is now rerouting the wastewater around the collapse to limit overflows.
- Work continues to clean out the pipe so crews can begin repairs.
- DC Water is testing the river for E. Coli. The sampling results are posted below.
- Drinking water is not impacted.
Media
By The Numbers
| Average Personnel on site daily: 31 | Average fuel to power generators daily: 3,200 gallons | Average equipment hours daily: 477 |
| 50 gallon bags of rags collected daily: 4 | Gravel hauled in daily: 25 tons | Debris hauled out daily: 12 tons |
Community Meetings
DC Water hosted two community meetings to provide a comprehensive update on the Potomac Interceptor response, current system status, and next steps in emergency repair and long-term rehabilitation efforts. DC Water officials and technical staff presented information directly and answered questions from community members.
District of Columbia Community Meeting
The first meeting was Wednesday, February 25 at DC Water Headquarters in the District. DC Water leadership and staff were joined by the directors of the District Department of Energy and Environment, Department of Health, and Homeland Security and Emergency Management Agency.
To see the presentation click here or watch a recording of the meeting below.
Maryland Community Meeting
The second meeting was held Thursday, February 26 at Walt Whitman High School in Bethesda. DC Water hosted the meeting in coordination with the Mayor of Glen Echo and Cabin John Citizens Association. Congressman Jamie Raskin provided opening remarks and officials from the Maryland Department of the Environment, Montgomery County Department of Environmental Protect, and the Montgomery County Department of Health and Human Services participated along with DC Water's leadership and technical staff.
Click here to see the presentation from this meeting or watch a recording of the meeting below.
What Happened
On January 19, 2026, a section of the 54-mile Potomac Interceptor (PI) sewer line collapsed along Clara Barton Parkway, in Montgomery County, resulting in a significant overflow into the C & O Canal National Historical Park. The PI carries about 60 million gallons of wastewater daily from as far away as Dulles Airport to the Blue Plains Advanced Wastewater Treatment Plant in Southwest DC for treatment.
DC Water crews and contractors began work immediately to construct a bypass to contain the overflow. The bypass was completed and activated on January 24, utilizing powerful pumps and the C&O Canal to reroute wastewater around the collapsed section of pipe and back into the sewer system. The focus now is on clearing debris from the damaged pipe so that crews can begin repairs.
As work progresses at the site, we are working to develop cleanup and remediation plans, which remain in the early stages and will be focused on immediately impacted areas such as the canal, drainage channels and portions of the Potomac River. Cleanup measures will be determined in conjunction with federal, state, and local regulatory agencies.
DC Water is providing daily updates on the progress to clean out and repair the PI. You can see the latest information by clicking on the links on the right side of this page.
Bacteria Sampling
Utilizing a contracted environmental firm and certified laboratory, DC Water initiated daily sampling for E. Coli, an indicator bacterium, at six (6) locations beginning on Jan 29, 2026, to assess water quality conditions, sampling locations including the overflow area as well as upstream and downstream sites. The locations are shown on the following map, and the results are provided in the table below.
Overall, results show mostly decreasing trends since the start of sampling, with elevated concentrations observed at the overflow site which is expected pending environmental rehabilitation. It’s important to note that historically the E. coli levels in the Potomac and Anacostia rivers vary widely from day to day. Fluctuations in water quality are influenced by many factors, from weather conditions such as precipitation, snowmelt, temperature variability, and other natural sources of E. coli bacteria such as wildlife. As a result, measurements taken much further downstream cannot be attributed solely to this incident.
A more detailed explanation is posted on the District Department of Energy and Environment (DOEE) website at doee.dc.gov/release/potomac-interceptor-update-and-faqs
DC Water’s E. Coli Sampling Locations
DC Water has added two new sampling locations to the daily sampling. These locations add data points closer to the overflow site. The Minnie’s Island sample locations are approximately 0.54 miles from the overflow site compared to the Fletcher's location which is 5.2 miles from the overflow site. These sample locations provide a better understanding of the impact in the river near the collapse site and allow us to compare the main stem of the Potomac River (south side sample) to the inlet areas along the shoreline around Minnie’s Island (north side sample) where the water flows more slowly.
*Lab results are unavailable on weekends and will be provided the following Monday (excluding holidays).
February 23 - present (Past results available here)
| E. Coli (MPN/100 ml) | ||||||||
|---|---|---|---|---|---|---|---|---|
| Sample Date | Old Anglers Inn (upstream of collapse) |
Near Drainage Channel @ Overflow (Swainson Island) | Between Minnie's Island and north shore of Potomac River | South Side of Minnie's Island | Fletcher's Boathouse | Georgetown @ Wisconsin Ave | Anacostia @ S. Cap St | National Harbor |
| 2/23/2026 | 204 | 1,100 | 299 | 299 | 461 | 613 | 687 | 304 |
| 2/24/2026 | 178 | 1,100 | 186 | 172 | 178 | 345 | 276 | 260 |
| 2/25/2026 | 58 | 500 | 58 | 63 | 66 | 249 | 210 | 105 |
| 2/26/2026 | 22 | 2,420 | 41 | 40 | 21 | 155 | 64 | 43 |
| 2/27/2026 | 16 | 1,730 | 51 | 20 | 5 | 1990 | 49 | 21 |
| 2/28/2026 | 9 | 5,400 | 43 | 10 | 8 | 41 | 30 | 15 |
| 3/01/2026 | 7 | 2,420 | 46 | 12 | 4 | 30 | 16 | 9 |
Consistent with public health and U.S. Environmental Protection Agency standards, swimming is not recommended when E. coli levels exceed 410 MPN/100 mL.
For the Potomac River, historical water quality data shows E. coli levels may vary from a range as low as 10 MPN/100mL to as much as 5,000 MPN/100mL on a given day.
Drinking Water is not Impacted
It’s important to note, DC Water's drinking water system is separate from the wastewater system, and we want to reassure the public the drinking water is safe, and water service is NOT affected by this incident. The overflow is downstream from the Washington Aqueduct’s (Aqueduct) intakes at Great Falls. In coordination with the Aqueduct, the intakes are also closed at Little Falls downstream.
Avoid the Area
The public is reminded to avoid contact with untreated sewage as it may carry bacteria and viruses. Anyone who comes in contact with the wastewater overflow should:
Leave the area immediately.
Wash exposed skin thoroughly with soap and clean water.
Disinfect any affected areas or items.
Do not consume food or water that may have been exposed.
Seek medical attention if symptoms occur.
Report exposure to DC Water at (202) 612-3400.
