Between 1,000 and 1,200 gallons of sewage spilled onto the ground and into Lake Lanier on Tuesday, according to a news release.

The Gainesville Public Utilities Department reports that the wastewater overflowed from a Thompson Bridge Road pump station, because a private contractor working on the pump station failed to close a valve completely while replacing a pump.

The contractor indicated that the discharge lasted approximately 20 minutes, according to the news release.

The area has been cleaned and signs are posted. Hall County Environmental Health and the state environmental protection division also have been notified, according to the news release.