Hobsons Bay Main Upgrade Project

The Hobsons Bay Main Sewer is a critical part of Melbourne’s sewer network, transferring around 30 percent of Melbourne’s wastewater to the Western Treatment Plant. The existing sewer was first constructed in the 1960s, it is now reaching the end of its service life and requires rehabilitation.

About the project

To stay up to date with this project and others in the Spotswood precinct, join our new Let's talk Spotswood Super Sewage Community Hub.

The sewer is located under the Yarra River between Westgate Park in Port Melbourne and Scienceworks in Spotswood. To rehabilitate the existing sewer, we are building a duplicate sewer which will allow sewage flows to be diverted during rehabilitation works. These critical works form part of a broader Melbourne Water sewer program on a number of ageing sewers around the city.

The current sewer is still functioning and there is no immediate environmental danger, however these critical sewer works are necessary to protect our future and will provide a significant increase in system capacity to cater for Melbourne’s growing population.

This project is part of Melbourne Water’s commitment to protecting Melbourne’s bays and waterways from environmental harm and ensuring the reliability of our sewer network.

Major works from June 2022 to October 2024

Since February 2022, the project team has established two construction sites at Scienceworks and Westgate Park. Tunnelling works have now been completed with tunnel boring machine 'Lucey' completing her 670 metre journey under the Yarra River in November 2023.

Over the coming months works will include:

• Tunnel grouting works
• Sewer connection works to connect the new sewer to the existing network
• Treatment and removal of spoil from site
• Permanent rehabilitation works.
• ​​ Project Timeline