We have a wide range of dam and rainfall data available on our website, to find out more detailed information, please click on one of the links below:

Rainfall data is updated daily at around 11am by the Bureau of Meteorology. We then publish these figures on our website as soon as possible. 

There are times when our data breaks or we may not have usable readings come through from our teams in the field.

For example if a dam does not have a reading we are not able to compare it to the same date last year.

Mistakes can happen so occasionally we will update historical data.

Our dam level data comes from each of our dams. Our larger dams all have a device that daily measures the volume in each dam. Our smaller dams have a measurement graph painted on the wall of the dam from which our teams take the reading when they go out to do our dam readings.

We report metro dam levels to one decimal place now due to the uncertainty in total dam volumes being greater than 0.4-0.5 gigalitres.

Please note that historical total dam volume data changed when we took over Stirling and Samson Brook dams.

We need steady regular rain to soak our catchments and get water flowing into our dams. Declining rainfall in Perth means that our dams receive much less streamflow than they used to. Streamflow is the amount of water entering our dams from our catchments and is measured by changing water storage levels.

The water in our dams is also no longer just made up of inflows from rain. Groundwater and desalinated water are also stored in our dams during periods of low demand, making it available in our warmer months, when it's most needed.

A number of our regional dams levels are recorded manually by our teams every 2-3 days. Please note that sometimes circumstances prevent levels from being read so there may be periods when data is unavailable.

Our rainfall data comes from the Bureau of Meteorology’s Perth CBD weather station ⁠— we display monthly rainfall totals for Perth, including a graph showing a monthly rainfall comparison.

You can view the monthly rainfall, year to date and seasonal rainfall for the past 4 years in a chart or table view.

For the years of 1994-2017 monthly rainfall data was supplied by the Bureau of Meteorology.

From 1876-2016 we recorded rainfall data at all our dams giving us our own historical records for this period.

Our streamflow figure includes the flow from all of our dams that supply the Integrated Water Supply Scheme and is recorded from May to April every year.

These figures include the Stirling and Samson Brook dams.

You can view our monthly streamflow data, including previous year’s pre and post 1975, which is when we took over 2 dams in Busselton.

You can view daily, monthly and current financial year water use on our 3 graphs for the whole Integrated Water Supply Scheme. The scheme which supplies the Perth metropolitan area and some parts of the South West and Goldfields.

Reducing the amount of water we use and meeting our targets will help secure a more climate-resilient water supply.

You can also see what our water sources are in a graph listing desalination, groundwater, dams and groundwater replenishment.

With climate change having a profound impact on our water supply, including hotter summers and lower rainfall, we must plan for our future by securing climate-resilient water sources.

View our water sources graph for more information on our water sources.