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.

Dam volumes, rainfall and water use data is updated every working day, streamflow is updated weekly.

Our water overview

Updated: Friday, 25 September 2020

Current

42.5%

268 GL

Last year

45%

284 GL

Change

5.7%

-16.2 GL

To 9am

0.00

mm

May total

May average*

32.20

mm

88.70

mm

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

Learn more about how our dam and rainfall data is updated.

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 has impacted our water sources

Water sources for our largest scheme, the Integrated Water Supply Scheme (IWSS), 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.

See how our climate has changed

In 2019-20 the breakdown of our IWSS water sources consisted of:

Desalination icon
%
Desalination
Groundwater icon
%
Groundwater
Dams icon
%
Dams
Groundwater replenishment icon
%
Groundwater replenishment

 

Latest dams & rainfall news

04 Sep 2020 | Media Release

Perth metro weekly water update

Latest water use, dam levels, streamflow and rainfall data

  • Dams
  • Climate change
  • Water sources
28 Aug 2020 | Media Release

Perth metro weekly water update

Latest water use, dam levels, streamflow and rainfall data

  • Climate change
  • Dams
  • Water sources