Melbourne Water Project Manager Paul Jackson said a total of 6.6 km of water main between Niddrie and Tottenham Railway Station, West Footscray, would be replaced over the next seven months.
Mr Jackson said work would move in 100 m sections, with the technique of sliplining used in some areas to minimise impact to busy thoroughfares.
The sliplining will see new pipe pushed through the old pipe without the need for excavation.
Built in 1928, the M102 water main is one of three water mains that services about 125,000 homes and businesses in Melbourne’s inner city and western suburbs.
The water main needs to be replaced to ensure it continues to provide optimal performance, without leaks and bursts and to service future demand for the next 150 years, concluded Melbourne Water.