Water Main Rehabilitation – St Kilda Road

Project Summary Sheet

Customer: South East Water

Location: St Kilda Road, VIC

Delivered: 2015

The Challenge

For South East Water, the asset owner, this was a critical project – not only because of the need to ensure 24 hour interruption free water supply, but also because of the reputational risk caused by continuous exposure working on such an important road.

The Solution

Interflow removed the old cast iron liner and directly replaced it with a larger PN16 polyethylene pipeline, whilst maintaining 24 hour water and fire service supply to all buildings. The road needed to be entirely open to traffic during the day and works could not interfere with tram services at anytime.

The Project

As part of Interflow’s five year water main renewal contract with South East Water, Interflow removed a 130-year old water main running under Melbourne’s iconic St Kilda Road with minimal disruption to commuters and the community. The DN250 cast iron water main was replaced with a larger 355 PN16 PE100 diameter polyethylene pipeline along the same route.

Works were carried out at night. Typically, Interflow set up about 200 metres of temporary above ground pipework parallel to the water main and diverted supply to it. Connections from this were made to each building.

After draining, about 20 metres of old main was removed each night and replaced with new polyethylene pipe. This would be connected to the previously laid section and backfilled.

By 6am next morning the trench would be totally filled and the road restored ready for the morning peak hour.

South East Water and Interflow worked together to ensure that community impacts were kept to a minimum.


Overall the new main has future-proofed water supply services along this section of St Kilda Road. It can reasonably be expected that the new polyethylene pipework will exceed the 130-year service life that the old main had been in service. The work was carried out while maintaining water and fire supply services and with minimal disruption to commuters.

Interflow is committed to offering its customers optimum solutions of the highest value for pipeline rehabilitation.