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Table showing target and actual water use, dam levels, streamflow and rainfall
Target Actual
March water use to date

22.8 billion litres

24.5 billion litres
Dam storage levels N/A 52.0%
Monthly streamflow into dams N/A 0 billion litres
March rainfall to date 19.5mm (March average rainfall 1876-2016) 2.0mm
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 979 million litres per day – above the demand forecast of 926 million litres per day.

Daily water use for the last five days

Table showing daily water use for the last 5 days
Date Actual water use (million litres) Forecast water use (million litres)
25/03/2022 947 914
24/03/2022 980 914
23/03/2022 932 915
22/03/2022 1034 915
21/03/2022 916 938
Note: water use is calculated up to 8am each day for the previous 24 hour period.

Since 1 July 2021 to date, we have used 232.99 billion litres of water – which is 9.39 billion litres above the forecast target for this period.

Dam levels (total for 15 dams)

The dam storage levels are slightly down on last week and are sitting at a combined 52 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 138.7 billion litres of streamflow. The post-1975 average for the May to April period (called the streamflow year) is 177.5 billion litres. 

Annual rainfall

Perth has received 3.6mm of rainfall since 1 January 2022. The average (1876-2016) rainfall for the same period to the end of March is 41.7mm.

General water news

This week we celebrated World Water Day 2022, which is a perfect time to reflect on the sustainability of our precious water resources in Perth and across WA.


Did you know that in Perth and southern parts of WA average annual rainfall has fallen by 20 per cent since the 1970s? Combined with longer, hotter summers and drier winters, this has seen an 80 per cent reduction in streamflow to metropolitan dams.


It’s been a long time since we could rely on rainfall alone to supply Perth’s drinking water, but many people still believe the water from their taps falls from the sky.


In Perth, nearly half our drinking water comes from desalinated seawater, while around 40 per cent comes from groundwater. A further 5 per cent comes from a innovative process called groundwater replenishment.


You can learn more about Perth’s water sources and find plenty of water-saving tips and tricks by visiting the climate and waterwise pages of our website.