In the first of a series on how to reduce the ecological footprint of your home, Michael Green takes a look at water tanks.
“Tanks do fill,” promises Nigel Finney from the savewater! Alliance. If you want to install one, do it before the good rain comes. “They fill in the wetter seasons,” Mr Finney says. “That’s when you can get maximum use out of them for your toilets and laundry.”
In January, the federal government introduced a rainwater tank rebate, adding to the Victorian government’s offer. Altogether, you can get up to $1500 back on your system – depending on its size and use. You get a higher rebate for bigger systems that are connected to your toilet and laundry by a licensed plumber.
A 5000 litre, plumbed tank will cost about $4000 to $5000, so even with the rebates it will set you back thousands of dollars. Mains water is very cheap, so the payback period is long.
On the plus side, a rainwater tank gives you an independent supply for your garden, so you can water your veggies even under tight restrictions. A tank also helps reduce stormwater pollution and eases pressure on dwindling dams.
What size tank is right for you? A good rule of thumb is enough capacity for four weeks’ supply. For use in the garden, laundry and toilets, that’s usually around 5000 litres – though be sure you have enough roof area to feed your tank. The savewater! Alliance website has a guide to average rainfall, roof-size and tank capacity (as well as product lists and handy advice).
“You can put a tank just about anywhere,” Mr Finney says. They come in all materials, shapes and sizes: steel, fibreglass, plastic or concrete; round, slimline or bladders; and capacities from 200 to 100 000 litres.
If you want value for money, go for plastic, round, large tanks. “The cost per litre drops off dramatically once you start getting over 2000 litres,” says Mr Finney.
Maintenance-wise, you’ll need to clean gutters and filters regularly. A ‘first flush diverter’ is useful to drain the dirty, initial water that comes from the roof during rain.
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