Find out our current and target daily, monthly and annual water use for the Integrated Water Supply Scheme, our largest scheme providing water for Perth, Goldfields and Agricultural Region and some parts of the South West.

Reducing the amount of water we all use and meeting targets will help secure a more climate resilient water supply.

Dam volumes, rainfall and water use data is updated every working day, streamflow is updated weekly. Learn more about how this data is updated.

Our water overview

Updated: Thursday, 29 October 2020



268 GL

Last year


284 GL



-16.2 GL

To 9am



May total

May average*





* Average monthly rainfall (for the period 1876 - 2016).

Water use in the metropolitan region and other areas

Actual water use and target water use reflect the whole Integrated Water Supply Scheme which supplies the metropolitan area and some parts of the South West and Goldfields.

How climate change is impacting our water sources

Water sources for our largest scheme, the Integrated Water Supply Scheme (IWSS) which supplies Perth, the Goldfields and Agricultural Region and some parts of the South West have changed dramatically. Water for the IWSS is now comprised of a combination of sources, including desalinated seawater, groundwater, groundwater replenishment and streamflow into dams.

Traditionally, Perth relied heavily on streamflow into our dams as a water source, but declining streamflow has meant dams now play a bigger role as storage reservoirs. The water in our dams is no longer just made up of inflows from rain. Groundwater and desalinated water are stored in these dams during periods of low demand so it is available when it is most needed in the hotter months.

How Perth's water sources have changed

In 2019-20 the breakdown of Perth's water sources (IWSS) consisted of:

Desalination icon
Groundwater icon
Dams icon
Groundwater replenishment icon
Groundwater replenishment