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

6.3 billion litres

6.6 billion litres
Dam storage levels N/A 60.4%
Monthly streamflow into dams N/A 5.58 billion litres
September rainfall to date 81.0mm (September average rainfall 1876-2016) 19.6mm
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 653 million litres per day – above the demand forecast of 632 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)
10/09/2021 618 640
09/09/2021 657 640
08/09/2021 692 640
07/09/2021 700 640
06/09/2021 634 621
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 44.56 billion litres of water – which is 2.01 billion litres above 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 60.4 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 102.8 billion litres of streamflow. The post-1975 average for the May to April period (called the streamflow year) is 175.5 billion litres.

Sprinkler roster compliance

Since 1 January 2021, we have taken a total of 4,449 actions (warnings + fines) compared with 4,315 actions for the same period in 2020.

Annual rainfall

Perth has received 676.0mm of rainfall since 1 January 2021. The average (1876-2016) rainfall for the same period to the end of September is 757.5mm.

General water news

Did you know that the water supplied to the Perth CBD and surrounding suburbs comes from a reservoir at Kaarta Gar-up (Mount Eliza) in Kings Park?


Well, this week it was announced that Mount Eliza Reservoir, which was Perth’s first public water supply scheme, is set to receive a major $7.7 million upgrade to ensure a reliable future water supply.


Works will involve replacing two ageing water pipe inlets, one of which is 94 years old, and the construction of a new regulating valve building, valve pit, and valve pit wall.


Read more here.