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

27.3 billion litres

25.3 billion litres
Dam storage levels N/A 61.3%
November streamflow into dams N/A 4.94 billion litres
November rainfall to date 22.4mm (November average rainfall 1876-2016) 34.6mm
Note: 1 billion litres = approximately 400 Olympic swimming pools.
* Data in table is current to November 30, 2022

Water use 

Week ending Daily average use
(million litres per day)
Daily average forecast  
(million litres per day)
28/11/2022 783 866
21/11/2022 831 832
14/11/2022 793 799
07/11/2022 746 767
Note: Average water use is calculated based on 7 days of data, from Tuesday 1 November through to Monday 28 November, 2022.

Since 1 July 2022 to date, the Integrated Water Supply Scheme (IWSS)* has supplied 107 billion litres of water - which is 6 billion litres below the forecast target for this period.

*The IWSS supplies Perth, the Goldfield and Agricultural Region and some parts of the South West.

Dam levels (total for 15 dams)

November's metro dam storage levels are slightly down from October and are sitting at a combined average of 61.3 per cent* of full capacity (or 386 billion litres). This time last year our metro dam storage levels were at 62.7 per cent* of full capacity (or 395 billion litres).


*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 85.8 billion litres of streamflow. The post-1975 average for the May to April period (called the streamflow year) is 177.1 billion litres.  

Sprinkler roster compliance

Since 1 January 2022, we have taken a total of 4,301 actions (warnings + fines) compared with 4,714 actions for the same period in 2021.

Annual rainfall

Perth has received 692mm of rainfall since 1 January 2022. The average (1876-2016) rainfall for the same period to the end of November is 844.5mm. The wettest day this month was 18 November, with 23.2mm of rainfall received in Perth.


The maximum temperature this month was recorded on 29 November at 36.2°C. The coolest day was recorded on 17 November at a maximum of just 16.4°C.


General water news

We’ve just launched a new campaign aimed at educating our community on the impacts of climate change on our drinking water supply.


Climate change has drastically affected where we get our water from. We always use the cheapest drinking water source first - streamflow (rainfall runoff) which is stored in dams. But rain is unpredictable.


We now have a growing reliance on more expensive, rainfall-independent drinking water sources. This includes desalinated seawater. That's water from the Indian Ocean that's had salt and impurities removed.


On average over the past five years, Perth has relied on desalinated seawater for around half of their drinking water supply.


Come on a virtual tour with us to understand the complex world of desalination -