Table showing target and actual water use, dam levels, streamflow and rainfall
Target Actual
June water use to date 4.7 billion litres
4.7 billion litres
Dam storage levels N/A 42.9%
Monthly streamflow into dams N/A 0.02 billion litres
June rainfall to date 173.1mm (June average rainfall 1876-2016) 0.6mm
Note: 1 billion litres = approximately 400 Olympic swimming pools. Please note the figures in this table are rounded (except for rainfall) to the nearest whole number.

Water use

Average water use over the past week was 669 million litres per day – below the demand forecast of 688 million litres per day.

Daily water use for the last 5 days

Table showing daily water use for the last 5 days
Date Actual water use (million litres) Forecast water use (million litres)
04/06/2021 655 679
03/06/2021 671 679
02/06/2021 681 679
01/06/2021 686 679
31/05/2021 697 699
Note, water use is calculated up to 8am each day for the previous 24 hour period.

Since 1 July 2020, we have used 277.29 billion litres of water – which is 0.82 billion litres below the forecast target for this period.

Dam levels (total for 15 dams)

The dam storage levels are slightly up on last week and are sitting at a combined 42.9 per cent* of full capacity.

*Please note some dams are filled from different sources - dam levels include the transfer of groundwater and desalinated seawater from treatment plants as well as streamflow (that comes from rainfall). As we use many different sources of water, dams are no longer an accurate indicator of the health of Perth's overall water supply situation.

Streamflow (total for 15 dams)

From 1 May 2021, the dams have received 1.5 billion litres of streamflow. The post-1975 average for the May to April period (called the streamflow year) is 175.58 billion litres.

Sprinkler roster compliance

Since 1 January 2021, we have taken a total of 2,398 actions (warnings + fines) compared with 2,598 actions for the same period in 2020.

Annual rainfall

Perth has received 236.2mm of rainfall since 1 January 2021. The average (1876-2016) rainfall for the same period to the end of June is 375.9mm.

General water news

Back in the 1970s, muddy or coloured water persistently made clothes a little less-whiter-than-white.


However, this dilemma was quietly overcome at our Mirrabooka groundwater treatment plant through an experimental process called SIROFLOC.


In this process, colour and suspended matter that clouds water (turbidity) are removed from surface and groundwater using magnetic powder (magnetite). The SIROFLOC process relies on magnetic forces to collect the matter we wish to remove from the water, which then forms clumps and quickly settles to the bottom of our clarifying tanks.


Read more about this little-known project that revolutionised Australian homes – and wardrobes – in the 1970s.