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In our metro weekly water update published last Friday, 10 August we indicated a technical difficulty with our streamflow reporting.


This issue has now been resolved and the streamflow and dam level data in the table below and on our website has now been corrected ^.


The issue was caused by a calibration fault on the instruments that calculate water levels at some of our dams.  The faults were identified following a storm event that also affected how the instruments ‘talk’ to our data collection system (SCADA).


While we have been repairing and re-calibrating the instruments, we have taken the opportunity to check data collected so far this winter.  We usually do this at the end of winter and then adjust streamflow and dam level figures accordingly.


The good news is through the data review process, and with the rainfall and extra streamflow we have received over the past two weeks, our dam levels are now at 56%.  


Thanks to those avid dam level watchers who have contacted us to ask why the data hasn’t been updating on our website recently.  As they say on TV, normal programming has now resumed and the data will be updated as per usual.  We do love a good storm here at the Water Corporation – but not when it affects our all-important dam level calculating instruments!






August water use to date

5 billion litres

5 billion litres

Dam storage levels ^



Cumulative streamflow into dams ^

25 billion litres

74 billion litres*

August rainfall to date

122.1 mm

(August mean rainfall 1994-2017)

101.6 mm

Note: 1 billion litres = approx. 400 Olympic swimming pools.  Please note these figures are rounded (except for rainfall) to the nearest whole number.


Water use


Average daily water use over the last week was 595 million litres, which was above the forecast of 549 million litres.  So far this current financial year we have used one billion litres of water more than the 22 billion litres we had forecast.


Dam levels


Perth’s dam storage levels have increased (by 19 billion litres) from 180 billion litres to 199 billion litres of usable storage (for the 1 August to 8 August period).   Please note our dams store water from three different sources and this increase is due to groundwater and desalinated seawater transferred from treatment plants as well as streamflow (produced by rainfall).


Streamflow (total for the metro’s 15 dams)


*We are experiencing a technical difficultly with our streamflow reporting this week.  As soon as the data becomes available we will include the information in this update and on our website.  From 1 May 2018 to 2 August 2018 the dams had received 33.8 billion litres of streamflow.


Sprinkler roster compliance


The Winter Sprinkler Switch-off now applies, and our inspectors issued 83 warnings and 17 fines this week.  Since 1 January 2018, we have taken a total of 5710 actions (warnings + fines) compared with 6814 actions for the same period in 2017.


Annual rainfall

Perth has received 580 mm of rainfall since January this year.  According to updated figures released by the Bureau of Meteorology the cumulative mean rainfall (1994-2017) for the Perth metro for the January to December is 732.8 mm.


General water news

At this time of year we see many of the open stormwater drains that Water Corporation and councils manage start to fill up.   It can be tempting, especially for children and dogs, to play in drains. 


Now is a good time to remind everyone to keep away from drains as they can become dangerous.  If a pet or child becomes caught in a drain it could cost them their life or endanger others who rescue them.


For more on drain safety please see

Media Enquiries:

Contact: Media Team

Phone: (08) 9420 2555