In South Australia, rainwater tanks are a vital part of new residential builds, highlighting the state’s strong commitment to sustainable water use. Regulations around their installation and use vary between local councils—especially between Adelaide and regional areas—so it’s important for homeowners and builders to understand these rules to ensure compliance and maximise the benefits of rainwater harvesting.

A key requirement for new homes is the mandatory installation of a rainwater tank. While the minimum capacity varies by council, most require at least 1,000 litres (1 kilolitre). This is separate from any additional tanks needed for bushfire protection. Local council guidelines may influence the size, location, and type of tank you choose, so it’s essential to check requirements specific to your area before making decisions.

In both Adelaide and wider South Australia, building rules also require that rainwater tanks be plumbed into essential household fixtures, such as toilets, water heaters, or cold water laundry outlets. This rule applies to new homes or extensions over 50 square metres and has been in place since 2006. Installation must be completed by a licensed plumber and comply with AS/NZS 3500 standards, including South Australian variations. Systems must also feature an overflow device and mosquito-proof screens to ensure safety and water quality.

Where rainwater systems are connected to the mains supply, backflow prevention is mandatory. This typically involves installing a dual check valve to prevent contamination. Additionally, pipes and outlets must be clearly labelled as “RAINWATER” to avoid confusion with potable water.

Ongoing maintenance is encouraged to ensure long-term safety and performance. While routine chemical or microbial testing isn’t required for domestic tanks, regular checks of the tank and plumbing system are recommended. For community or commercial systems, however, regular water quality testing is compulsory to meet health standards. Tanks must also be securely installed on a stable base, as a full tank can weigh several tonnes and pose a hazard if not properly supported.

In summary, South Australia’s rainwater tank regulations are designed to support safe and effective water storage across new developments. By following these guidelines and consulting your local council, you’ll not only ensure compliance—but also support broader conservation efforts. Whether you’re building in Adelaide or regional SA, understanding the rules will help you make the most of your rainwater system.