The project, which began in August this year, has now been completed ahead of schedule.
The works replaced a 561 m section of pipe between King William Street and Pulteney Street.
SA Water worked with South Australian company SEM Utilities to deliver the project.
SA Water’s General Manager Operations and Maintenance Mark Gobbie said SA Water has engaged with local businesses, Adelaide City Council and the Department of Planning, Transport and Infrastructure throughout the works.
“SA Water and the project team worked to ensure impacts on the public were minimised.
“SA Water would like to thank businesses, residents, road users and pedestrians for their patience during the process,” he said.
The replacement of the water main was fast-tracked after a burst in June earlier this year affected local Grenfell Street businesses, morning commuters and traffic within the vicinity.SA Water’s water main burst rate is currently the lowest it has been since detailed records commenced in the early 1990s.