We Want to Hear from You
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Community Engagement
DC Water has hosted a series of community meetings to provide a comprehensive update on the Potomac Interceptor response, and to answer questions from residents and stakeholders. Thank you to everyone who participated in one of one of the meetings in the District, Bethesda and Alexandria. Click on the Engage button below to watch videos of the meetings or download the presentations.
Environmental Rehabilitation 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 remediation efforts based on input from concerned residents and community groups, along with the ongoing collaboration with federal, state, and local regulators overseeing the environmental remediation.
If you would like to share any comments about the Environmental Rehabilitation Plan with the project team, please click on the button below.
Comprehensive Condition Assessment
On Thursday, March 5, DC Water released a comprehensive assessment detailing the condition of the Potomac Interceptor and our emergency response to the January 19 sanitary sewer line failure. This report provides clarity for customers, stakeholders, and community members about the steps taken and findings from the incident, including prior inspections of the pipe’s condition.
Click here to view the report and pipe inspection videos.
We detailed our findings in this Press Release.
Background
- Collapse of 72" diameter section of pipe caused overflow of more than 200 million gallons of wastewater into Potomac River.
- Bypass system rerouted the wastewater around the collapse to limit overflows.
- Emergency repairs are complete and full flow was returned to the Potomac Interceptor on March 14.
- DC Water is testing the river for E. Coli. The sampling results are posted below.
- Drinking water is not impacted.
Media
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 with four more locations later added, to assess water quality conditions, sampling locations including the overflow area as well as upstream and downstream sites.
It's important to understand that rain, snow, heat, contaminated runoff, and natural sources of E. coli such as wildlife can cause higher bacteria levels in urban rivers such as the Potomac. After heavy rain experts recommend avoiding the water for at least 48-72 hours. This is reflected in the data, where significant spikes are seen that coincide with rain and weather events but then return to normal. With no overflows to the river for more than a month prior to completion of emergency repairs, fluctuations in measurements are more likely due to these known factors.
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 and DOEE Water Quality Sampling Locations
*Lab results are unavailable on weekends and will be provided the following Monday (excluding holidays).
March 9 - 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 | Sycamore Island | Lock 6 | Fletcher's Boathouse | Georgetown @ Wisconsin Ave | Anacostia @ S. Cap St | National Harbor |
| 3/16/2026 | 13 | 21 | Not sampled | Not sampled | 20 | 17 | 3700 | 2420 | 34 | 23 |
| 3/17/2026 | 236 | 186 | 199 | 184 | 770 | 579 | 222 | 816 | 238 | 46 |
| 3/18/2026 | 816 | 435 | 326 | 548 | 2,420 | 1,200 | 179 | 488 | 345 | 46 |
| 3/19/2026 | 344 | 272 | 326 | 291 | 4,100 | 1,410 | 461 | 649 | 285 | 75 |
| 3/20/2026 | 60 | 37 | 50 | 40 | 517 | 162 | 71 | 328 | 156 | 46 |
| 3/21/2026 | 12 | 38 | 13 | 12 | 3,300 | 197 | 98 | 185 | 77 | 142 |
| 3/22/2026 | 15 | 27 | 8 | 8 | 152 | 76 | 20 | 116 | 75 | 31 |
| 3/23/2026 | 12 | 18 | 8 | 10 | 34 | 18 | 308 | 579 | 25 | 16 |
| 3/24/2026 | 3 | 8 | 3 | 3 | 15 | 11 | 8 | 33 | 25 | 21 |
| 3/25/2026 | 1 | 14 | 4 | 12 | 3 | 2 | 5 | 12 | 25 | 17 |
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.
Understanding the Data and How it Compares
*Data Provided by DC Department of Energy and the Environment
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.
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 an average of up to 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.
Within five days, DC Water crews and contractors constructed a bypass to help contain the overflow. On January 24, utilizing powerful pumps and the C & O Canal, wastewater was rerouted around the collapsed section of pipe and back into the sewer system. The last overflow to reach the Potomac River occured February 8, and within 21 days all overflows were contained.
Additional pumping capacity was brought in, and a bulkhead gate installed to block flow in the pipe to allow for emergency repairs. As work to repair the pipe continued, DC Water also developed its initial Environmental Rehabilitation Plan in conjunction with state and federal regulators. Clean-up efforts in the areas directly impacted by the overflows began on March 2.
Emergency repairs were completed on March 14, and the flow was successfully returned to the Potomac Interceptor. Once this occured, the bypass pumps were turned off allowing the C & O Canal to drain and for work to get underway to clean and rehabilitate the canal.
Construction has now transitioned to the previously planned long-term rehabilitation of more than 2700 linear feet of the Potomac Interceptor in this area. The work is expected to take 9-10 months and will strengthen and reinforce the pipe to like-new condition.
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.
