Do I need a rainwater tank, and is the water safe to drink?

New South Wales, South Australia and the ACT commonly ask a new home for a rainwater tank, while Queensland and Victoria leave it to councils and estates. Kept clean, tank water can be safe to drink, and the first Australian study of PFAS in rain found Melbourne’s levels well below the national guideline.

Does a new home need a rainwater tank?

BASIX in New South Wales weighs a tank by its size, the roof that drains to it and what it supplies, often the toilets, the laundry and a garden tap. South Australia asks for a tank plumbed to a toilet, the water heater or the laundry. The ACT asks for a tank, a greywater system or a design that meets its mains water target another way. Queensland dropped its statewide rule in February 2013, though a council can still require tanks. Victoria’s rule that a new home take a tank or solar hot water ended in May 2024.

Where does a tank go on the site plan?

Beside the roof that feeds it, at a downpipe of the house or a shed, and behind the front building line. The plan shows its footprint, its distance to the boundaries, the downpipes, the pump, a note of what it supplies and the overflow line to the stormwater point, which must not send water onto the neighbour’s lot. In a flood overlay, the post on flood overlays covers what the council asks.

Do you need council approval for a water tank?

Often not, for a small one. In New South Wales a tank is exempt when, among other things, it stays under the size the code names, keeps clear of the boundary once past a set height and sits behind the building line. On a heritage item it goes in the backyard. In some states a tank past the size the scheme names counts as a structure that needs approval.

Is tank water safe to drink?

Kept clean, it can be, though health departments advise town water for drinking where it reaches the lot. Where the house lives on tank water, keep the gutters clear, the inlets screened, the first flush device emptied and the tank sealed.

PFAS are long-lasting chemicals once common in firefighting foam, and the worry about them in rain comes from a 2022 study by Stockholm University and ETH Zurich. It judged rain against the advisory the United States issued that year, set so low that rain fails it almost everywhere, even in Antarctica. Australia’s guideline, updated by the NHMRC in June 2025, rests on what a person can drink daily for a lifetime without harm, so it sits higher. The study that RMIT University and EPA Victoria published in September 2026 found the PFOS and PFOA in Melbourne’s rain well below it, from a small set of rain events.

Boiling and a first flush device do nothing for PFAS, which falls in the rain itself. A reverse osmosis unit, or an activated carbon or ion exchange filter independently tested for PFAS, can reduce it if it is serviced on time. Australia has banned making and importing PFOS, PFOA and PFHxS since July 2025, with narrow exceptions.

Reading it for your own lot

RapidSiteplan reads the lot from its address: the boundaries over the aerial photo, the buildings and any tank already there, and the overlays where they are published. Place the new tank and the sheet dimensions it to the boundaries. The shed and carport page shows the sheet, and the council pages for every state show what each council maps. Start with the address.

Common questions

Do I need a rainwater tank, and is the water safe to drink? It depends on the state: New South Wales, South Australia and the ACT commonly ask a new home for one. Kept clean, the water can be safe to drink, and the first Australian study of PFAS in rain found Melbourne’s levels well below the national guideline.

Do you need council approval for a water tank? Often not, if it stays within the size, height and boundary distance the state’s code names. Past those, it counts as a structure that needs approval.