01.Saving rain

In brief

• Rainwater tanks are no longer just huge, round and ugly; they come in all shapes and sizes to suit the urban and suburban home.
• Watering the garden and washing the car with rainwater make sense and cuts your consumption of mains water. But bigger savings can be made if you connect the tank to your toilet, washing machine or hot water system.

Australia is the driest inhabited continent and predictions are that the future is likely to get hotter and drier. So it’s all the more frightening that, per person, we’re the biggest water consumers in the world.

But drinking water is scarce. Of all the water in the world, only 1% is fresh water available for use. So it’s hard to justify that we waste so much of this precious resource on things that don’t really require good drinking water. Garden irrigation and toilet flushing, for example, apparently guzzle up around half the water we consume.

Using rainwater for these things, or recycled greywater from our baths and laundries, would make much more sense.

Harvesting the rain

In the past, rainwater tanks were a common feature of the Australian landscape, but they’ve almost disappeared from our cities now. The majority of Australian households get their water from a reticulated supply (mains or town water). In the 1990s, 16% of households used a rainwater tank and for 13% it was their main source of drinking water.

In recent years, however, the long-lasting drought in many parts of the country and widespread water restrictions have drawn attention to water conservation issues and put rainwater tanks right back onto urban agendas. Many local councils, water suppliers and state governments have been encouraging residents to install a rainwater tank, usually with the offer of a rebate.

The benefits

The potential benefits of installing a rainwater tank are plentiful, and you don’t need to live in a wet or tropical area to reap them. South Australia, the country’s driest state, has the highest rate of rainwater tank usage. More than half the households there have one, and for more than a third it’s their main source of drinking water.
With a rainwater tank, you’ll:

• Collect most of the rain (around 80%) that falls onto the areas of your roof you have connected to gutters and downpipes into your tank. For example, if 10 mm of rain falls on to 100 m2 of roof you’ll ‘harvest’ about 800 L of rainwater. That’s about as much as an average Sydney household of three would use in a day if they made no efforts to save water. If they did, they’d get their consumption down to around 500–600 L a day.
• Reduce your consumption of mains water and, in the long term, cut your water bill. Your water supplier may be able to give you an indication of the savings you can expect.
• Lower your impact on the environment by reducing your demand on mains water as well as the amount of stormwater runoff into rivers and oceans.
• ‘Harvest’ water that tastes better and is generally less salty, which is better for appliances and plants.