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Urban dwellers can take a tip from rural households and harvest rainwater for watering the garden and for use in appliances. Installing a water tank helps you conserve this liquid asset, harnessing a resource that would otherwise disappear down stormwater drains. It will save you money and it will also help reduce your environmental impact.
If you have a roof, chances are you can use it, along with gutters and drainpipes, to collect rain into a water tank. Once you’ve harvested the rainwater, you can then pump it to outlets such as your garden taps, as well as indoor appliances like the washing machine and toilet.
Tip: The only issues for collecting non-potable rainwater (water not fit to drink) occur when a roof is made of unsealed asbestos. If you’re unsure what your roof is made of, consult a licensed builder.
Although the water tank itself can be a D.I.Y. installation, there are important decisions to be made beforehand, such as where to position and direct the overflow pipe. You’ll need a licensed plumber to connect the pipework and to install a backflow device to prevent rainwater escaping into the public water system. If you require a pump and auto-switching device, you’ll also need to get a licensed sparkie to deliver a power supply. It’s possible your local water authority may have to approve the installation, too, so check all requirements with them before getting started.
For those building a home from scratch or doing a ground-up renovation, it may be compulsory to include a rainwater tank in your plans. Check with your local authority.
Rainwater tanks come in a range of sizes, styles, colours and materials, from small planter-style containers up to whoppers built for commercial use. For existing homes, slimline tanks between 1000 and 8500L, made from materials such as polyethylene or steel, can be tucked down the side of the house. They come in a range of standard colours, so you should be able to find a match for your home’s scheme.
Tip: Council approval isn’t usually necessary for tanks up to 10,000L, but as regulations differ and affect decisions like positioning, consult your local council or planning authority before you make your choice.
The size of water tank you’ll need depends on various factors, including average rainfall for your area, what you plan to use the water for and how many people live at home. As a guide, a four-person household (with access to mains water and an evenly spread rainfall) looking to use rainwater for flushing the loo, running the washing machine and watering a small garden should opt for a 3000 to 5000L water tank.
The aim is to have as much of your roof as possible available for rainwater catchment, so consider that when planning a location for your water tank. This will also depend on the space available, as well as local regulations. Clever water tank placement can also be more economical and convenient, says Mark Pearson from Clark Tanks.
“The closer the tank is to your water source, the less money you will spend on plumbing and pipework from your roof to the tank inlet strainer,” he says.
Even a small tank can be very heavy when filled, so it will need a solid base (such as concrete) to rest on and should be properly secured so it won’t blow over when empty. Water tanks can’t be placed over public water or waste pipes; ask your supplier for advice.
Essentials for your new rainwater tank include screens for your inlet and overflow pipes to prevent critters like rodents and mozzies getting in, as well as a first flush diverter. “It allows the first flush of rainwater from your spouting to go straight to overflow until the downpipes and gutter are flushed of contaminants; then the diverter shuts off to fill your tank,” explains Mark.
A pump will almost certainly be required to drive the water to where it needs to go. These can be external or – for a quieter, space-saving choice – submerged within the tank.
For ongoing maintenance, keep trees and leaves well away from your gutters, says Mark. “Ensure the inlet strainer is regularly cleaned out so water can flow freely through its stainless-steel mesh,” he adds. “Gutters should also be cleaned out regularly to maintain the quality of roof run-off into your water tank.”
Tip: Fitting gutter guards will help fend off leaf litter, while downpipe covers are a must to keep out blockages.
Another way to eke out your usage is to use the grey water from appliances like your washing machine (not the toilet) in the garden. But you can’t use it everywhere, says Tim Wilson of Ames Australasia, suppliers of Nylex hoses.
“Grey water is mostly used on lawns and grass,” he says. “It’s not recommended to reuse the water on vegies or edible plants.”
Simply attach a grey water hose to your washing machine outlet and run it into a bucket or straight into the garden via a dispersion hose. “Grey water is not meant to be stored for longer than 24 hours, and it should be spread out evenly so it does not pile in the same place,” says Tim.
Check out our water tank range.
Some products are not available at all Bunnings stores, but may be ordered.
Photo Credit: Gap Photos/Nicola Stocken
Asbestos, lead-based paints and copper chromium arsenic (CCA) treated timber are health hazards you need to look out for when renovating older homes. These substances can easily be disturbed when renovating and exposure to them can cause a range of life-threatening diseases and conditions including cancer. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer or visit our Health & Safety page.
When following our advice in our D.I.Y. videos, make sure you use all equipment, including PPE, safely by following the manufacturer’s instructions. Check that the equipment is suitable for the task and that PPE fits properly. If you are unsure, hire an expert to do the job or talk to a Bunnings Team Member.
