Table showing target and actual water use, dam levels, streamflow and rainfall
Target Actual
March water use to date 4.9 billion litres
4.2 billion litres
Dam storage levels N/A 44.2 per cent
Monthly streamflow into dams N/A 0 billion litres
March rainfall to date 19.50 mm (March average rainfall 1876-2016) 34.00 mm
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 864 million litres per day, which was below the forecast of 984 million litres.

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)
05/03/2021 775 975
04/03/2021 773 975
03/03/2021 798  975
02/03/2021 789  975
01/03/2021 948  995
Note, water use is calculated up to 8am each day for the previous 24 hour period.

Since 1 July 2020, we have used 201.17 billion litres of water – which is 2.15 billion litres below the forecast target for this period.

Dam levels (total for 15 dams)

The dam storage levels have decreased slightly this week and are sitting at a combined 44.2 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 2020 the dams have received 42.5 billion litres of streamflow. The post-1975 average for the May to April period (called the streamflow year) is 176.73 billion litres.

Sprinkler roster compliance

Since 1 January 2021, we have taken a total of 1,136 actions (warnings + fines) compared with 1,656 actions for the same period in 2020.

Annual rainfall

Perth has received 72.8 mm of rainfall since 1 January 2021. The average (1994-2019) rainfall for the same period to the end of March is 51.6 mm.

General water news

This week we headed into Autumn, and gee it’s been a wet one already. Since 1 March, Perth has received 34mm of rain, which is a 74 percent increase from the March average (calculated on average rainfall 1276-2016).


Although the downpour has been wonderful for our dams and our gardens, heavy rainfall events and cyclonic activity are becoming more intense and unpredictable as a result of climate change, leading to flash flooding and damaging winds which can wreak havoc across the state.


This was evident in the town of Northam this week, when the Wheatbelt centre received a heavy rainfall event in a short amount of time, leading to flash flooding in the streets.


Water Corporation always advises West Australians to avoid contact with floodwater, as we don’t know what is in floodwater at any given point in time and it may contain things that can harm health.


Flood water can contain downed power lines, physical objects such as vehicles and debris, wild or stray animals such as rodents and snakes, and other contaminants that can lead to illness, including wastewater.


While Water Corporation takes measures to avoid any impact to our infrastructure in the event of a flood, there are times when floodwater can be contaminated by wastewater due to loss of power at a wastewater treatment plant, so we ask people to avoid floodwater as a precautionary measure.


If you do encounter floodwater, it’s important to:


  • Avoid access chambers (manhole) that appear to be discharging water.
  • Wash your hands and affected areas of the body thoroughly with clean warm water and soap, especially before eating.
  • Change out of dirty clothes and wash clothes separately.
  • Contact your doctor immediately if you experience any illness.


For more advice on what to do in the event of a flood please click here.