Rainwater Tanks

Water tank installation is encouraged to make better use of our water resources.


A planning permit is NOT required for a domestic rainwater tank with a capacity less than 4,500 litres unless the property is located in a Heritage Overlay and the tank would be visible from a street or public open space. A building permit is NOT required for a freestanding domestic rainwater tank as it is not classified as a building. A building permit is required, however, if the tank is structurally supported by a building, in which case structural adequacy and wall setback allowances need to be checked.


Rainwater tanks allow for the storage of some of the stormwater from the roof. However, the tank must be fitted with an overflow pipe of the same diameter as the inlet pipe which must be connected to a stormwater drainage system that discharges to a legal discharge point.


Rainwater collected by tanks is usually NOT suitable for drinking as it may have contaminants from collection surfaces. Tanks need to be sealed to prevent the entry of insects (eg mosquitos), vermin and other animals. Unsealed tanks are also a risk to small children.


The water tank system should divert the initial quantity of water collected from roofs to exclude contaminants such as leaves, atmospheric pollution, animal droppings and other matter that may be washed into the tank. The tank must be professionally designed and manufactured using corrosion resistant, non-toxic materials. Any support stands must be professional designed and constructed to meet all structural requirements and be in accordance with any manufacturer's recommendations.


The State Government of Victoria has introduced a rebate scheme for purchase of waterwise products such as rainwater tanks connected to toilet cisterns. Other purchases that are entitled to a rebate are:

  • Grey water systems
  • AAA dual flush toilets
  • AAA shower roses
  • High pressure cleaning devices
  • Water conservation home audits
  • Variopus garden products (if over $100 is spent)

Full details of the rebate scheme can be found at the Our Water Our Future webpage of the Dept of Sustainability & Environment.

Regulations for a Sustainable Future

Under successive changes to building regulations in Victoria all new homes and new renovations must now be designed to be energy efficient. The house energy rating (HER) system of the Sustainable Energy Authority of Victoria is used to measure energy efficiencies and a special Victoria amendment to P2.6.1 of the BCA applies to efficient use of water.

From 1/05/2008 the 5 Star energy rating applies to new, renovated and relocated homes. Under a state variation to 3.12.0 of the BCA applying to Victoria, the deemed-to-satisfy measure for compliance is that new homes have either a rainwater tank connected to all sanitary facilities or solar a hot water system.

Further information on rainwater tanks

Department of Human Services

Building Commission 5 star page