Nebraska City Utilities reported an unplanned discharged of wastewater into South Table Creek on Sunday.
An estimated 21,000 gallons were discharged between 10 a.m. and 5 p.m. on March 7.
Wastewater Collection Superintendent Tom Liesemeyer said pumps at a lift station near south Ninth Street did not operate properly.
Pumps at five lift stations normally lift discharge from low lying areas to resume flow to the wastewater treatment plant.
Liesemeyer said pumps at the lift station lost their prime for some reason and did not turn on when the water level rose. The discharge went into an overflow pipe that leads to the creek.
Liesemeyer said corrective action was taken after a utilities employee noticed warning lights.
Failure at the lift station was last reported Feb. 26 when there was a power outage.
The utility estimated that 21,045 gallons were discharged over a 12-hour period.
