Courtesy of CHOICE
Rainwater tanks come in a variety of sizes, shapes, materials and colours. You can install one next to the house, on top or under it, on a stand, on the ground or below it. Installing a tank below ground is generally more expensive because of excavation costs, but the tank's out of sight.
- Cover: All tanks should have a tight-fitting cover so animals and children can't get access, water won't be lost through evaporation and light doesn't enter, which could promote the growth of algae.
- Size:The tank capacity you need depends on what you want to use it for, the size of your household and garden, your roof area and the annual rainfall in your region. Your water authority may be able to help you work out the size you need or many sellers of tanks provide calculators on their websites.
Sydney Water recommends a minimum tank size of 5000L in an urban environment if you want to use the water for toilet-flushing, the washing machine and in the garden (but not for drinking water). Brisbane City Council estimates that a 3000L tank connected to the hot water system, toilet and for outdoor use can result in 30 to 40 percent savings of mains water.
- Type: You can choose from round, rectangular (modular) and slimline tanks. Round ones come either upright or squat, which may fit well under decking or the like. Slimline tanks are generally a bit smaller, but are popular with people who have limited space. There are also newer alternatives to the traditional shape — a few of these are noted below.
- Material: Metal tanks are made from corrugated or flat rolled metal and can be galvanised or coated. They often come with a plastic inner lining (Aquaplate) that'll increase the life of the tank and protect the water quality.
Polyethylene (poly) tanks are durable and because rust isn't an issue, tend to be recommended for people living near the ocean. Concrete tanks can be bought ready-made or custom-made on-site. Fibreglass tanks tend to be more expensive: they're rust and chemical-resistant and designed to withstand extreme temperatures. They're more suitable for above-ground installation, while all other types can also be installed below ground.
- Location: To reduce water loss through evaporation from inspection holes, don't put it where it'll be in the path of the hot midday sun.
No space for a tank?
We've come across a couple of clever alternatives (which we stress we haven't tested or even touched) if you have no space at all for a standard tank or don't like the look of one. It'd be worth checking your local area for others if you're in that position.
The Rain Reviva underfloor storm or grey-water management system consists of sacs (much like sealed, flexible bladders) that you can fit into small or irregular spaces, such as under the house. It's largely DIY (unless you want to connect it to your water supply) and costs upwards from $2300 for a 2200L sac, pump and fittings. Larger and irregularly shaped sacs can be custom-built. For more information, go to www.rainreviva.com.au or phone (03) 8873 3600 or 1300 552 695.
The Waterwall modular rainwater storage system consists of slim, connectable polyethylene tanks that will fit into narrow spaces such as under eaves or that can be installed freestanding as fence or garden dividers. The system is available from Bunnings Warehouse, Reece Plumbing, Tradelink Plumbing Supplies and other outlets. Each module holds 1200L and costs $1070, including a wall fixing bracket (a freestanding frame costs $195 and a joiner kit $29.95). For more information, go to www.waterwall.com.au or phone (03) 9689 3055.
