Saving for a (Non) Rainy Day
Install a design-smart water tank now to start collecting winter's watery bounty for the summer
Catherine Smith
8 June 2016
Houzz New Zealand Contributor. A design addict from way back, I can't resist looking at other people's houses. And doing a tiny bit of styling and decluttering. Just a tiny bit.
Houzz New Zealand Contributor. A design addict from way back, I can't resist looking... More
Now that the winter rains have arrived, it’s hard to remember how dry the garden gets through summer and early autumn – and how hefty the water bills become. But this is the smart time to invest in a water tank so you can collect nature’s free supply that winter so generously brings – and start hoarding for when the rains dry up again. But forget the big round tanks on the stand beside the house that were a standard beach or rural sight in New Zealand for so long, because now that townies have gotten in on the water-collecting act, city style has arrived.
Vicki Niethe and her husband Clint of Tanksalot have decades of experience helping homeowners select the right tank, eventually introducing the slimlines that are common in Australia. They are discreet enough to fit into restricted spaces, but Vicki’s advice is to go big – both the size of the tank and the amount of roof run-off you direct into it. At a minimum, she recommends a 5000-litre tank if you live in an area with year-round rain. For her family of four adults, she’s found that is plenty to supply two toilets, laundry, dishwasher and two outside taps. Some tanks are as slim as 600mm.
When you’re building new or extending the footprint of non-permeable surfaces on your property (that means swimming pools or concrete driveways, as well as buildings) most councils now require you to install a retention tank to catch rainwater. This means that after a rainstorm, water is gradually eased into the stormwater system as sudden, heavy water flow can flood old systems, causing stormwater and sewage to merge – not pretty.
Tanks will also need an overflow pipe for when the tank is full. Incredibly, one square metre of roof area produces one litre of water for every millimetre of rain, so you’ll want to maximise the roof area feeding to your tank to collect every precious drop. It doesn’t take long to use up the water. Vicki points out that running a garden hose uses nearly 1000 litres an hour, so make sure your tank will suit your water-use requirements.
Tanks will also need an overflow pipe for when the tank is full. Incredibly, one square metre of roof area produces one litre of water for every millimetre of rain, so you’ll want to maximise the roof area feeding to your tank to collect every precious drop. It doesn’t take long to use up the water. Vicki points out that running a garden hose uses nearly 1000 litres an hour, so make sure your tank will suit your water-use requirements.
You will need a first-flush diverter that diverts the initial flow of dirty water from the roof (from dust, for example, or heavy metals from nearby roads) which drains the contaminants to a soakage area, before allowing the following clean water into the tank. A leaf strainer prevents debris from clogging up the tank (and decaying inside) and that will need be cleaned out frequently.
Tanks have to have a flat, well-supported base (1000 litres of water weighs one tonne). A reinforced concrete slab or well-levelled concrete pavers are best. If you want to put the tank on a stand, you’ll need engineering advice to ensure the structure can take the weight of the tank and water. Tanks and stands need to meet Building Research Association of New Zealand (BRANZ) standards.
Tanks can also be fitted under a deck. Here thousands of litres of water will be safely stowed away under an expansive deck. This will require careful engineering design, and access to check filters – it isn’t a job for amateurs.
If you’re siting the tank near the house, consider a colour that disappears (the darker the better) or surround it with planting that will help it merge. But be careful if you are espaliering trees or growing creepers that the wires and frames are well clear of the tank so that growth doesn’t damage the surface of the tank.
9 ways to a more sustainable garden
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If you want to go further, and use the water in the house, you will need a plumber to bring water from the tank into the house. This is a marginal cost for a new build, but Vicki warns that retrofitting pipes and plumbing to the toilet or laundry can cost up to $10,000 for new fittings and labour. You may need to check your council regulations too, as tank water must be isolated from the mains water, and will need a building consent.
Check websites such as Ministry of Business, Innovation and Employment (MBIE)’s Smarter Homes for regulations. Some councils provide subsidies for retrofitting rainwater systems, so check your local council, water company or eco-advisory service.
Check websites such as Ministry of Business, Innovation and Employment (MBIE)’s Smarter Homes for regulations. Some councils provide subsidies for retrofitting rainwater systems, so check your local council, water company or eco-advisory service.
For just outside use, site the tank where you’ll use it with a tap. Near the vegetable garden or beside the garage for washing the car are good spots.
If you have nowhere to hide the tank, consider framing it with a slatted fence (you will need to give yourself access for the tap, and to clear the leaf filter).
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Or you could be out and proud. Here Australian architectural designers Rustic Touch have put the tank front and centre. There’s no mistaking it, it’s called the Tank House
A terrific modern bush house in the middle of the suburbs by
Matt Elkan won an Australian Institute of Architects NSW award in 2014. The water tanks are part of a program that helps the house sit lightly on the land, the simple old-school corrugated iron tanks referencing old-school Aussie farmhouses.
Matt Elkan won an Australian Institute of Architects NSW award in 2014. The water tanks are part of a program that helps the house sit lightly on the land, the simple old-school corrugated iron tanks referencing old-school Aussie farmhouses.
TELL US
What are you doing to collect and use rainwater in your house and garden? Tell us in the Comments.
MORE
The Lowdown on Rainwater Tanks
Let it Rain: 20 Questions to Ask Before Installing a Water Tank
No Brainer Ways You Could Be Saving Water
What are you doing to collect and use rainwater in your house and garden? Tell us in the Comments.
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The Lowdown on Rainwater Tanks
Let it Rain: 20 Questions to Ask Before Installing a Water Tank
No Brainer Ways You Could Be Saving Water
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But wait! There's a terrific modular water storage system out there called 'rainwaterhog' . It's won awards in Australia, where it originated, and USA, but for some reason isn't stocked in hardware stores. I installed mine myself, and it can even sit horizontally under floor boards(fits between the joists) . Look it up online. Designed by Sally Dominguez, Australian architect/designer now living in California.
Thanks kooky_karen, I have been looking for something like this for some time for my tiny yard.