Water supply

Melbourne has some of the highest-quality drinking water in the world. Learn how it makes its long journey from forested catchment areas to your tap: from collection, storage, treatment to transfer. 

Environmental water release at Starvation Creek

What makes up our water supply network:

  • 156,700 hectares of catchments
  • 10 storage reservoirs
  • 2 major treatment plants
  • 12 minor treatment plants
  • 38 service reservoirs
  • many kilometres of pipes

How the water supply system works

Step 1: Collection

Water catchment areas have sponge-like soils that filter and hold rainwater, then slowly release it into the rivers that feed our water storage reservoirs. Most these catchments have limited public access, producing very clean water that needs little treatment. In times of critical need we can also use water from the Victorian Desalination Plant and North–South Pipeline.

Step 2: Storage

Water rests in our storage reservoirs for up to five years, which helps improve its quality as impurities break down over time. Our reservoirs are interconnected, allowing us to move water when we need to. For example, we might move water out of a reservoir so it can fill up during heavy rain, or direct less water to treatment plants that cost more to operate.

Step 3: Treatment

After leaving our reservoirs, water is purified at our water treatment plants so it is safe to drink. Most of our water needs very little treatment, but water from open catchments is fully treated to meet strict water quality guidelines.

Step 4: Transfer

Water then travels through large pipes, called water mains, to smaller service reservoirs throughout suburban Melbourne. These hold water for a few days to make sure there’s always some on hand, even when demand is high.

Smaller pipes carry this water to our customers: the metropolitan and regional retail water companies. They also own thousands of kilometres of pipes that transfer water to homes, schools and businesses across Melbourne.

Monitoring water quality

We check water quality throughout the system, testing for over 100 substances to make sure our water meets safety and quality requirements. These are set by the Department of Health and Human Services, Australian Drinking Water Guidelines and our bulk water supply agreements with the retail water companies.

Last updated:
11 December 2019