DC Water Admits Critical Mistake: Potomac River Has 100 Times More E. Coli Than Reported

Utility says human error led to inaccurate reporting of contamination levels following major sewage spill.

Published on Feb. 10, 2026

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DC Water, the major water provider for the Washington, D.C. area, has admitted to a critical error in its reporting of E. coli levels in the Potomac River following a major sewage spill in January. The utility says the actual E. coli levels were 100 times higher than what it had initially reported to the public, with the real levels reaching 242,000 MPN/100mL compared to the previously reported 2,420 MPN/100mL.

Why it matters

This revelation raises serious concerns about the safety and cleanliness of the Potomac River, a vital waterway for the D.C. region. The significant underestimation of E. coli contamination could have public health implications and underscores the need for greater transparency and accountability from DC Water regarding the management of the city's water infrastructure.

The details

The high E. coli levels stem from a massive sewage spill that occurred on January 19 from the 72-inch Potomac Interceptor pipeline. DC Water has stated that the spill does not impact the drinking water system, as the wastewater system is separate infrastructure. However, the utility acknowledged a "human error" in its internal review process that led to the inaccurate reporting of contamination levels. As a result of the spill, an estimated 243 million gallons of waste have gushed into the Potomac River, enough to fill 368 Olympic-sized swimming pools.

  • The sewage spill occurred on January 19, 2026.
  • DC Water announced the critical error in its E. coli reporting on February 9, 2026.

The players

DC Water

The major water provider for the Washington, D.C. metropolitan area.

Potomac Interceptor

A 72-inch sewage pipeline that experienced a major spill, leading to the contamination of the Potomac River.

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What they’re saying

“We identified a human error through internal review, corrected it immediately, and updated the information as soon as it was confirmed. Sampling and monitoring have continued.”

— DC Water (DC Water website)

“We regret this mistake and have implemented additional quality control measures to ensure the accuracy of the data reported.”

— DC Water (DC Water website)

What’s next

DC Water has stated that the clean-up process could take months to address the significant sewage contamination in the Potomac River.

The takeaway

This incident highlights the critical importance of accurate water quality reporting and the need for robust oversight and accountability measures within utility companies tasked with managing vital public infrastructure. The significant underestimation of E. coli levels raises serious concerns about the safety and environmental impact of the Potomac River spill, underscoring the need for greater transparency and proactive steps to prevent such errors in the future.