ACT Water Cycle

Water flows through an ongoing cycle, called the natural water cycle. This is the continuous movement of water between the land, oceans and the atmosphere. Water is always cycling around, through and above the earth. As it flows through the cycle, water changes its state from liquid to steam (gas) or ice (solid) and back to (liquid) water. 

ACT Water Cycle Diagram

Water vapour rises into the atmosphere, where the air is colder. The colder air causes water vapour to condense into water droplets and clouds. Water falls from the sky as rain, sleet, hail or snow. Surface water from lakes, waterways turn into water vapour and rises into the air. Water vapour is released into the air by plants and trees. When water does not soak into the ground it runs-off into gullies, streams and rivers. When water falls on the ground as rain, hail or snow, it can soak into the ground.


The drinking water from our taps is part of this ongoing water cycle. When clouds get heavy, water falls as rain, sleet, hail or snow (precipitation). It is in the highest points of the landscape where water runs off the mountains of the Cotter River east of Canberra, and off the Queanbeyan River mountains to the south west. These areas are known as catchments. The water in the rivers are held in one of our four water supply dams -  Corin, Bendora, Cotter and the Googong Dam. Water that flows into these dams  becomes part of the ACT urban water cycle. 

From the dams, water begins its journey through the treatment process via pipelines and pumping stations to the Water Treatment Plants at Mount Stromlo or Googong.  

At the water treatment plants, the raw water goes through a process of filtration, disinfection by chlorination and UV treatment, to provide high quality drinking water ready to travel to our suburban water reservoirs. From the reservoirs located on the high points of hills, gravity helps to transport the water around the suburb, flowing underground through over 3300 kilometres of network pipes to our homes for drinking, washing and cleaning.   

The water we use in our kitchens, bathrooms, laundry and toilet drains to the sewer system. The sewer network takes the used water that is flushed down the drain from all of Canberra's residents and businesses to the Lower Molonglo Water Quality Control Centre in Belconnen to be treated, processed and cleaned. At the Centre, physical, chemical and biological processes treat the water to a high standard. The water is such high quality it is returned to the Murrumbidgee River before it takes the journey via the Murray river system to the sea near Adelaide, the next part of the natural water cycle.
Transpiration Evaporation Condensation Precipitation Infiltration Surface Runoff