A major water provider in the Washington, D.C., area admitted on Feb. 9 that the company made a critical error in its reporting of e coli levels to its customers.
DC Water first announced that the water levels were going down to much lower levels following the Potomac Interceptor sewage spill in the Potomac River, The provider then disclosed that human error led to inaccurate reporting on e. coli levels for the area. The real levels were 100 times worse than the company had initially reported.
The difference in the data set is drastic. “The previous data indicated 2,420 MPN/100mL when the results were 242,000 MPN/100mL,” the update read.
These heightened levels stem from a massive sewage spill from the 72-inch Potomac Interceptor pipeline which took place Jan. 19, 7News WJLA reported. DC Water has said that the spillage does not impact the drinking water system because the waste water system is a separate infrastructure. (RELATED: DC Sewage Breach Sends Human Waste Gushing Into Potomac, Causes Dangerous Contamination)
NBC 4 Washington reporter Mark Segraves highlighted the admission on X, prompting questions and criticism. DC Water issued a response.
“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,” they wrote.
After reporting ecoli rate at sewage spill in Potomac River was going down, @dcwater now admits they released very incorrect data. It’s actually 100 times higher than they reported.
DC Water Reporting Error
Reported: 2,420 MPN/100mL
Actual : 242,000 MPN/100mL @nbcwashington pic.twitter.com/7vI4HE4Wwa— Mark Segraves (@SegravesNBC4) February 10, 2026
DC Water acknowledged the mistake and suggested internal changes are set to be in place in the update on their website.
“We regret this mistake and have implemented additional quality control measures to ensure the accuracy of the data reported,” the update continued.
As a result of the spill, some 243 million gallons of waste have gushed into the historic river as of early Feb. 10, according to 7News WJLA. For context, this amount of fluid is enough to fill 368 Olympic-sized swimming pools, the outlet noted.
The clean-up process could take months to address, DC Water said.