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Check dam volumes and rainfall and find out how declining rainfall is affecting the amount of water (streamflow) flowing into our dams. In this section you can also learn where our water comes from and how our water use is tracking.

Our water overview

Updated: Monday, 15 April 2024 Learn more about how this data is updated

* Average monthly rainfall (for the period 1876 - 2016).
Dam volumes, rainfall and water use data is updated every working day, streamflow is updated weekly.

How declining rainfall impacts our water supply

We need steady, regular rain in order to soak our catchments and get water flowing into our dams. Slowly declining rainfall means Perth's dams receive much less streamflow than in past years. Streamflow is the amount of water entering our dams from our catchments and is measured by changing water storage levels.

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.

Learn more about how the impact of climate change continues to affect rainfall, the streams that flow into our dams and water use.

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

Perth's water sources at a glance

In 2022-23 the breakdown of Perth's water sources (IWSS) consisted of:

Desalination icon
%
Desalination
Groundwater icon
%
Groundwater
Dams icon
%
Dams
Groundwater replenishment icon
%
Groundwater replenishment
A sandpit with steps leads towards the water's edge of the lake at North Dandalup Dam

Visiting our dams

Our dams are a great spot to visit. Find out how you can make the most out of your visit and learn more about their historical and natural attractions.

Visiting our dams

 

Latest dams & rainfall news

08 Feb 2024 | Media Release

Innovative water-saving trial extended across dams in southern WA

Innovative floating covers that reduce evaporation by more than 70 per cent have been installed at three dams in southern agricultural areas.

  • Complete
  • Dams
  • Great Southern
  • South West
Dam
31 Jan 2024 | Media Release

Ord Dam safety warning as spillway overflows

Water Corporation has closed Pannikin Bay to ensure public safety as the Ord Dam overflows following heavy rainfall in the East Kimberley.

  • Dams
  • North West
ord river