Crews have repaired a blocked manhole that led to a sewage spill earlier this week in south Forsyth.

A Forsyth County sewer crew discovered the overflowing manhole Monday afternoon near McGinnis Ferry and Sargent roads, according to Jill Pilcher, county water and sewer department executive assistant.

Classified as "minor," the spill involved about 5,500 gallons of sewage, some of which reached nearby Johns Creek, Pilcher wrote in an e-mail.

The crew cleared the blockage causing the overflow about an hour after discovering it.

Located in a sewer easement, the manhole is not in the road and the overflow was not visible to passing motorists.

"The area was cleaned, limed and strawed," Pilcher wrote. "As required by Georgia [Environmental Protection Division], signs were posted and monitoring has been set up."

It hasn’t been determined what caused the blockage, she wrote, but several types of debris in the lines could have been factors.

The backup is the third minor spill this year for Forsyth. The county found and cleared three in 2010, two in 2009 and one in 2008, according to Pilcher.