Are rainwater tanks required for a dual occupancy?

Not necessarily. A dual occupancy must demonstrate compliance with the ACT’s applicable water-efficiency requirements, including a target of 40% reduction in mains water use compared with an equivalent development constructed in 2003.

ACT Planning treats dual occupancy as multi-unit residential development for this assessment—the Multi-unit Waterways Calculator specifically covers developments from dual occupancy through to multi-storey apartments. The calculator considers rainwater tanks alongside other water-saving measures, including water-efficient fixtures and greywater systems.

Therefore, a rainwater tank is not automatically required simply because the development is a dual occupancy. A tank may form part of the design used to demonstrate compliance with the required water-efficiency target.

Reference: ACT Planning, Water Efficiency - https://www.planning.act.gov.au/professionals/regulation-and-responsibilities/responsibilities/water-efficiency