Water supply system

​As the wholesale supplier of Melbourne’s drinking water, we are responsible for an extensive water supply system. We manage Melbourne’s water supply catchments, treat drinking water and transfer it to our customers – Melbourne’s three retail water companies – who in turn supply individual homes and businesses.

Find out how the water supply system works and our role in ensuring a safe and reliable supply of water for Melbourne.

From catchment to tap

Water travels a long way from the catchments to your tap, through reservoirs, treatment plants and many kilometres of pipes.

Collecting and harvesting water

Water catchment areas in the north and east of Melbourne capture rainfall and direct it into our major storage reservoirs. Most of our drinking water comes from protected catchments with limited public access, so it is very high quality to begin with.

While the catchments are our primary source of drinking water, in times of critical need we now have other supply options like the Victorian Desalination Plant and North-South Pipeline.

Learn more about our sources of drinking water:

Storing water

Water rests in our storage reservoirs for up to five years, which helps improve its quality.

Our 10 storage reservoirs are interconnected, making our water supply system very flexible. We transfer water around the system to manage it in the best way possible, such as moving water out of a reservoir so it can fill up during heavy rainfall, or directing less water to treatment plants that cost more to operate.

Read more about each of our storage reservoirs:

Treating water

After leaving our storage reservoirs, water is treated at our water treatment plants so it meets water quality requirements and is safe to drink.

Most of our water needs very little treatment since it comes from protected catchments, but water from open catchments is fully treated to make sure it also meets water quality guidelines.

Learn about the water treatment process at our plants:

Transferring water to homes and businesses

After treatment, water flows through large pipes to smaller service reservoirs. These hold water for a few days to ensure a constant water supply even when demand is high.

We own 38 service reservoirs located around suburban Melbourne, which range in capacity from 2 to 250 million litres. They are often in elevated areas so water can be transferred via gravity, which is less costly and power-intensive than pumping water.

From our service reservoirs, water flows through smaller pipes to our customers – the metropolitan and regional retail water businesses. They own thousands of kilometres of pipes that carry the water in a web-like network to every home, school and business across Melbourne.

Monitoring water quality

Throughout the water supply system we test for over 100 substances. This ensures our water meets safety and quality requirements set by the Department of Health and Human Services, Australian Drinking Water Guidelines and our bulk water supply agreements with the retail water companies.

Our sophisticated monitoring and treatment processes make sure Melbourne’s drinking water meets very high standards, which you can read more about on the following page:

Did you know?

Nine hydro-electricity plants at our reservoirs use energy from moving water to generate about one-sixth of our electricity needs.

 
Renewable energy

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