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

9.2 billion litres

9.7 billion litres
Dam storage levels N/A 50.2%
Monthly streamflow into dams N/A 0 billion litres
May rainfall to date 116.9mm (May average rainfall 1876-2016) 14.4mm
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 833 million litres per day – above the demand forecast of 763 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)
12/05/2022 802 753
11/05/2022 779 753
10/05/2022 854 753
09/05/2022 835 775
08/05/2022 826 775
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 274.28 billion litres of water – which is 10.58 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 50.2 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 2022, the dams have received 0.0 billion litres of streamflow. The post-1975 average for the May to April period (called the streamflow year) is 174.8 billion litres. 

Annual rainfall

Perth has received 98.4mm of rainfall since 1 January 2022. The average (1876-2016) rainfall for the same period to the end of May is 202.8mm.

General water news

Every Western Australian has a personal responsibility to take care of our precious water resources.


Last week, Water Corporation was incredibly pleased to celebrate the water saving efforts of participants in our business, development, and local government waterwise programs.


Congratulations to this year’s Platinum Waterwise Winners City of Joondalup, Bayswater Waves, Crown Perth, D’Orsogna, QV1 and OneOneFive Hamilton Hill by Development WA, who went above and beyond to achieve excellent water savings in 2021.


Learn about their waterwise initiatives here.