About 30 properties were affected after a water main was turned off between Mittagong and Colo Vale.
The main was shut down on January 11 to allow essential upgrade works to be carried out following the installation of the new road bridge in Willow Vale.
A council spokeswoman said customers were not notified about the upgrade, as prior assessments indicated there would be minimal interruption to water supply.
“The main in question had been isolated previously with no known customer impacts,” she said.
“Once we started receiving calls about the water interruption, we were able to restore supply to specific areas before midday.
“Works were scheduled to be conducted after the morning peak demand, with the aim to be completed before midday.”
After water was restored, some residents reported water discolouration. Council crews attended those areas to flush the mains.
Council has since apologised for the inconvenience.
The spokeswoman thanked customers for their continued support and understanding during ongoing works and upgrades to water and sewer infrastructure in the area.
Learn more about town water at http://www.wsc.nsw.gov.au/dirty-water.