Table showing target and actual water use, dam levels, streamflow and rainfall
Target Actual
May water use to date 20.6 billion litres
21.3 billion litres
Dam storage levels N/A 42.5%
Monthly streamflow into dams N/A 0.76 billion litres
May rainfall to date 116.9mm (May average rainfall 1876-2016) 74.4mm
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 703 million litres per day – below the demand forecast of 709 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)
28/05/2021 686 699
27/05/2021 690 699
26/05/2021 706 699
25/05/2021 677 699
24/05/2021 711 720
Note, water use is calculated up to 8am each day for the previous 24 hour period.

Since 1 July 2020, we have used 272.61 billion litres of water – which is 0.68 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 42.5 percent* 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 0.8 billion litres of streamflow. The post-1975 average for the May to April period (called the streamflow year) is 175.63 billion litres.

Sprinkler roster compliance

Since 1 January 2021, we have taken a total of 2,274 actions (warnings + fines) compared with 2,536 actions for the same period in 2020.

Annual rainfall

Perth has received 199mm of rainfall since 1 January 2021. The average (1876 - 2016) rainfall for the same period to the end of May is 202.8mm.

General water news

Winter Sprinkler Switch-Off


Don’t forget, June 1 marks the annual Winter Sprinkler Switch-Off for households in Perth, Mandurah, and parts of the South West and Great Southern.


By simply switching off your reticulation in winter we can collectively save around 5 billion litres of water. To put that into perspective, that’s enough to fill Optus Stadium 5 times!


It’s never been more important to conserve every single drop as we help to combat the impacts of climate change. To find out if you are included in the switch-off, please visit


Share a snap of your waterwise verge to win!


Does your street have a waterwise verge? Waterwise verges are a great way to create sustainable green spaces, all while helping cool our streets, reduce urban heat, and save water.


Water Corporation is offering residents the change to win a waterwise gardening package of their very own by simply taking a photo of their favourite waterwise verge.


Visit Water Corporation’s website and get snapping before Friday, 4 June to enter.