As a result of the recent high rainfalls and subsequent flooding Melbourne Water is working with emergency services and other relevant agencies to review the impacts to our waterways and assets. 

For flood or storm emergency assistance, contact the VIC SES on 132 500 and for life threatening emergencies call 000. 

You can access current emergency information by calling the VicEmergency Hotline on 1800 226 226 or sign up to receive regular updates regarding flooding via the emergency.vic.gov.au website and app.


The Victorian Desalination Plant was built to meet our growing water needs as we face ongoing challenges from population growth and climate change. Learn how it works and the role it plays in securing our water supply.

Why we need a desalination plant

Victorian desalination plant
The Victorian Desalination Plant at Wonthaggi, in Victoria's south east.

The Victorian Desalination Plant plays a critical role in Melbourne’s water future.

It was announced as a project during the Millennium Drought when water storage levels were critically low (16.5% in our largest reservoir), and can now deliver up to 150 billion litres of high-quality drinking water a year.

That’s around one-third of Melbourne’s annual water needs – or around 60,000 Olympic swimming pools.

But because it can only meet part of our annual water demand, it needs to be used proactively to:

  • build a buffer in our storages, by regularly topping up our reservoirs
  • take pressure off our reservoirs during drier periods and droughts.

The Department of Environment of Land, Water and Planning manages the contract with the plant’s operator, AquaSure.

Take a look at the plant from above:

How desalination works

desalinated water outlet at Cardinia
Desalinated water entering Melbourne’s water supply network at Cardinia Reservoir.

The desalination plant removes dissolved salts from seawater, using a reverse osmosis process.

This produces high-quality drinking water that meets our strict quality requirements (like all our water), including standards set by the:

  • Australian Drinking Water Guidelines
  • Victorian Safe Drinking Water Act
  • World Health Organization.

Before entering Melbourne’s water supply system:

  1. Water quality is first tested at the desalination plant in Wonthaggi, and again at all delivery points.
  2. Desalinated water travels towards Melbourne through an 84-kilometre two-way pipeline – with pipeline offtakes enabling South Gippsland and Western Port to receive water from the plant, and from Melbourne, if needed.
  3. Desalinated water enters our supply network at Berwick and flows on to Cardinia Reservoir, where it mixes with water from our catchments.
  4. Water can then be transferred to Silvan Reservoir and on to most of Melbourne.

The plant’s power requirements are 100% offset by renewable energy.

Watch this video for more information:

Last updated:
24 September 2022