South Australia is under Level 1 restrictions with some additional restrictions.
New houses built in South Australia are now required to install a rainwater tank of at least 1000 litres. The tank must be plumbed into the toilet, to a water heater or to all cold water outlets in the laundry, and the inlet and overflow must be fitted with mosquito proof screens.
The same rules apply to new extensions or alterations with an area greater than 50m2 that include a toilet, water heater or laundry cold water outlet.
In most cases, development approval is not required to install a rainwater tank on an existing home or business. Exceptions are tanks over 10m2 and 4 metres in height, including stand need Development Approval.
The tank capacity you need depends on what you want to use it for, the size of your household and garden, your roof area and the annual rainfall. The Adelaide mean annual rainfall varies from over 1100mm in the Adelaide Hills to around 400mm near the sea.
It is a common misconception that a tank for garden watering is the best way to save water. While you can save a significant amount of water this way you will need a very large tank, and you can usually save more water by connecting a smaller tank to your toilets or washing machine which are used regularly all year round.
For more information about rain water tanks contact Council's Development team via 8384 0666 or email@example.com.
State government also publishes a number of publications on the installation and maintenance of rain water tanks, available at https://www.sa.gov.au/topics/energy-and-environment/water/rainwater-tanks.