Covering roughly 10,500 hectares of land (or the size of Phillip Island) the WTP is nestled along the coastline of Port Phillip Bay and is bordered by the Werribee River to the east, the Princes Highway to the north and the Avalon Airport to the west.

The site has important indigenous and European cultural heritage values, including places of Indigenous spiritual significance for the Wadawarrung Traditional Owners and the historic sewage farm workers township site of Cocoroc.

In 2021, the WTP was added to the Victorian Heritage Register and officially recognised for its historical, archaeological and technical significance to Victoria.

The Western Treatment Plant’s variety of wetland and grassland habitats provide a refuge for wildlife, including some of the world’s rarest bird and frog species – such as the critically-endangered Orange-bellied Parrot and the Growling Grass frog.

In 1983, the site was declared an internationally-significant wetland for waterfowl under the Ramsar Convention. More than 300 bird species have been recorded at the plant, attracted to the water and food in its permanent wetlands, making it one of Australia’s best places for birdwatching.