Final stage of major works to expand CBD sewer network
28 May 2026
Greater Western Water's $160 million project to expand Melbourne's oldest sewer network is another step closer to completion, with major works underway for the fourth and final stage of the project.
The works will see about 750 metres of underground sewer pipes constructed along Siddeley Street, from Spencer Street and Flinders Lane to Wurundjeri Way, connecting them to the existing network.
The expansion of the sewer network forms part of GWW's Melbourne CBD Sewer Strategy, a major investment to strengthen Melbourne's wastewater infrastructure.
As part of the first three stages of the project, new underground sewer pipes have been installed in Elizabeth Street, Lonsdale Street and Spencer Street.
GWW General Manager Asset Planning and Delivery Ian Burton said the expansion of the sewer was designed to help future-proof the Melbourne CBD's sewer network.
"Melbourne's underground sewer network has played a crucial role in protecting public health and the environment for the past 120 years," he said.
"These are vital works designed to strengthen the sewerage system's capacity and reliability as Melbourne CBD's population continues to grow and thrive.
"Not only will the completed project double the capacity of the existing sewer network, it will support more dwellings and offices in the CBD for at least another 100 more years.
"We want to thank the community in advance for their patience and understanding while our valued construction partner Saunders Aqua Metro delivers this critical infrastructure upgrade at Siddeley Street."
Works on this final stage to expand the capacity of the existing network are expected to be complete by 2028.
