As water restrictions tighten up, our guide to rainwater storage shows you how to save on water and keep your garden in the green.

WORDS ANNA MCCOOE

If a green garden is a somewhat distant memory and every load of washing leaves you wincing at the waste, installing a rainwater tank might just lighten your step. If you don't believe you have the space, time or money, consider that rainwater storage is changing. Not only are designs becoming more advanced and more adapted to suburban gardens, state and territory governments have increased their rebate schemes, making now the perfect time to invest. Plus, by harnessing fresh water that falls free from the sky, you stand to save thousands of litres of town water and about $150 on your water bill each year!

Sizing Up The Opportunity
The general consensus in rainwater tanks is that bigger is most definitely better. "An average four person household uses 7000 litres of water a week and would need a tank of at least 5000 litres to suffice. A larger tank will also last you longer should a dry spell hit," says Julian Gray, chief executive officer of Smart Approved WaterMark. If space is of the essence and you don't want to over cater, look to the size of your roof (the catchment area) to work out exactly what you need. As a general rule, every millimetre of rain that lands on every square metre of your roof produces one litre of water. Check with the Bureau of Meteorology for the average rainfall in your area each year (visit www.bom.gov.au) and multiply that amount by the size of your catchment area.

Beyond The Eyesore
In order to focus your attention on the lush greenery and thriving blooms in your rainwater-run garden, the latest rainwater units now master the art of camouflage. We're spying slimline tanks designed to hide in the service passage of your home, steel tanks available in the same colour as your roof and custom poured concrete tanks that sit underground or in planter boxes. "From an architect's point of view, hiding the tank underground or under a deck is the best solution because you get full use of your garden," says landscape architect David Vago of Habitation. Just keep in mind that underground tanks are more expensive because you have to pay for excavation and a pump to deliver water up to the house. "If your only option is an above-ground tank, work the shape of the tank in with the shape and style of the garden. For instance, a circular tank works best in an organic garden, while a rectangular tank works nicely in a formal garden or a modern courtyard."

Material Matters
Choosing the right material may be overwhelming but there's a simple guideline to follow. If you're building from scratch or renovating,concrete tanks, which tend to keep water cooler and prevent algal growth, can be poured onsite to sit underground or within structures sparing precious floorspace for outdoor entertaining. Metal tanks are lightweight and come in a wide range of colours to match your roof, gutters or to blend in quietly under a canopy of green. Remember to ask about a plastic liner which will increase the life of the tank and the quality of the water. Polyethylene tanks also come in a wide range of colours but tend to be more streamlined, and well suited to a modern setting. Because rust isn't an issue, they tend to be your best option if your home hugs the coast.

The Big Spend
According to Environment Victoria (www.envict.org.au), the cost of installing a typical 5000 litre tank is $2500 to $3000 but this price is slashed almost in half when you apply for a government rebate (depending on the state or territory you live in). With a tank this size, you can also expect to save at least $150 on your water bills each year,so a tank can pay for itself within about 10 guilt-free years of gardening. When pondering the costs of a rainwater tank, it's also worth contacting your local council as they might provide added incentives or savings.

Smart Approved WaterMark has a full list of local council rebates on its website, www.smartwatermark.info.