Washington, D.C.‘s Water and Sewer Authority significantly miscalculated the level of E. coli coming from a sewer line channel on Friday after a late January pipe collapse caused increased levels of the bacteria in the Potomac River.

On Friday, Feb. 6, DC Water initially reported levels of E. coli at 2,420 MPN/100mL, then changed it to the actual level of E. coli present, 242,000 MPN/100mL, which is 9,900% higher than the initial report. The numbers came from a drainage channel at Swainson Island, adjacent to Cabin John, Maryland, in the Potomac River.