Virginia officials released the first downstream water quality data after a major sewage discharge from Maryland’s collapsed Potomac Interceptor, showing low bacteria levels in Prince William and Stafford county waters.
Key Takeaways
- Date: February 20, 2026
- Sampling Conducted: February 17, 2026
- Location: Potomac River from Chain Bridge to Stafford County, including Prince William County and Woodbridge
- Virginia agencies reported no elevated fecal coliform or E. coli levels in downstream Virginia waters.
- The Virginia Department of Health tested shellfish waters from Colonial Beach to the Route 301 Harry Nice Bridge.
- Woodbridge marina operators are refusing to post state-issued warning signs and are conducting independent water testing.
Full Coverage
The Virginia Department of Environmental Quality (DEQ) and the Virginia Department of Health (VDH) on Friday released initial bacteria sampling results tied to the collapse of the Potomac Interceptor in Maryland, which discharged a large volume of sewage upstream of Virginia’s portion of the Potomac River.
The results were posted to a dedicated page on DEQ’s website and reflect samples collected Feb. 17 along approximately 49 miles of the Potomac River and its tributaries. Sampling stretched from Chain Bridge near the District of Columbia border south to the mouth of Potomac Creek in Stafford County.
VDH analyzed 36 water samples from shellfish growing areas between Colonial Beach and the Route 301 Harry Nice Bridge. According to the agency, none of the samples showed elevated fecal coliform concentrations, and most were at or below laboratory detection limits.
Fecal coliform bacteria are used to assess potential contamination from sewage and to determine whether shellfish-harvesting waters meet state health standards.
DEQ conducted additional testing at 25 locations in the mainstem Potomac River and nearby tributaries. The agency reported that all mainstem stations were below the U.S. Environmental Protection Agency’s recreational contact threshold of 410 most probable number (MPN) of E. coli per 100 milliliters.
In Prince William County, sampling at Quantico Creek — approximately 100 yards upstream of the railroad bridge — showed E. coli levels of less than 10 MPN per 100 milliliters, according to DEQ data.
The data release comes as tensions grow in Woodbridge, where several marina operators opted to conduct independent water testing before deciding whether to post state-issued warning signs tied to the Maryland sewage spill.
Marina owners say they need more site-specific information about conditions near their docks before erecting signs urging people to avoid contact with the water.
The Potomac Interceptor collapse occurred upstream in Maryland. Virginia officials said they will continue coordinated monitoring to assess any downstream impacts.
As of mid-February, state agencies report minimal to no detectable fecal contamination in Virginia’s lower tidal Potomac waters.
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This article was created with AI assistance and reviewed by Potomac Local News editors for accuracy and clarity.
