Quick answer: The main rainwater tank options are slimline poly tanks for narrow spaces, steel tanks for larger capacity, and underground tanks when there is no room above ground. A good install includes a first-flush diverter, pump and backflow protection.
Rainwater tanks make a lot of sense in Sydney. We get long dry spells, then a month’s rain in a weekend. A tank catches that water for the garden, the toilets and the washing machine, cuts your water bill and takes pressure off the stormwater system. Here’s a plain guide to the main options I install and what suits which kind of home.
Slimline poly tanks
These are the most common ones I put in for terraces and smaller blocks. They’re narrow, so they fit down the side of the house or along a fence, and they’re made of UV-stabilised plastic that won’t rust. Get one that’s food-grade if there’s any chance you’ll use the water for more than the garden.
Steel tanks
Round or slimline steel tanks are tough and hold a lot of water if you’ve got the space. Look for a proper internal lining, since an unlined steel tank will eventually rust.
Underground tanks
If you’ve got no room above ground, a tank can go under the driveway, lawn or deck. Modular systems can be fitted into awkward spaces. They cost more to put in because of the digging, but you don’t see them at all.
Tanks for new builds and renovations
If you’re building or doing a big renovation in NSW, your BASIX certificate may require a rainwater tank of a certain size, plumbed to toilets, laundry or garden taps. Check your BASIX commitments before you buy, and we’ll make sure the install matches them.
Getting the plumbing right
- First-flush diverter: stops the dirtiest water off the roof going into the tank
- Pump: needed if you want the water at toilets or the washing machine
- Mains backup: switches to mains water automatically when the tank runs dry
- Backflow protection: keeps tank water from getting back into the mains supply, which is a requirement
The tank is the easy bit. Most problems I see come from how it’s connected: pumps that cycle on and off all day, no first-flush diverter, or overflow running against the house footings.
If you’re thinking about a rainwater tank anywhere around Ryde, Epping, North West Sydney or the North Shore, call me on 0451 001 503 and I’ll tell you what size and type makes sense for your place.
Quick questions
New builds and some major renovations in NSW may require one. Check your BASIX certificate.
Yes, with a pump and a mains backup system installed by a plumber.
