Rainwater tanks
Installing rainwater tanks at your home is a great way to save water by capturing your own water supply. If you are looking for a tank here are some issues you need to look into.
Siting and access
The first decision you have to make is where the tank will be located and access. If you have a large yard with lots of space and easy access to get the tank in you will have a number of options. You could place it next to the house, elsewhere in the yard, or even under the house. Where you locate the tank will determine its size and shape, and possibly even its colour if it needs to blend into the surrounding vegetation or buildings.
How big a tank do I need?
The ideal size of your rainwater tank will depend on what you want to use the water for, the number of people in the household, and also your budget, roof size and rainfall.
Here is a rough guide:
| Use of water | Tank size (litres) | |
| Garden | 5000+ | |
| Toilet and laundry | 5000 | |
| Hot water | 10 000 | |
| Whole house | 15 000 | |
| Whole house & garden | 20 00 | |
Tank types
Tanks come in a range of shapes and sizes. Rainwater tanks can be round or slimline, bladder style for under the house or deck, or prefabricated or assembled onsite for underground. If you do not have a lot of space, then slimline tanks can be a great solution, or you could place bladder tanks under the house.
The most common rainwater tank materials are plastic (usually polyethylene), metal and concrete. Polyethylene tanks are a popular choice for above ground tanks. They are durable and most can simply be installed onto a sand base or pavers, or even partly into the ground if needed. They typically come with at least a 10 year guarantee and can be recycled at the end of their life.
The iconic metal tank is typically corrugated metal with either a Zincalume or Colourbond finish. Metal tanks need to be installed on a concrete base or reinforced pavers. They are typically guaranteed for at least 20 years and can be recycled at the end of their useful life. If you have a lot of space larger metal tanks from 25,000 to over 2000,000 litres can be assembled onsite.
Concrete tanks are less common these days, but can be a good above or below ground option. They can be prefabricated or constructed onsite.
Bladder tanks are great for placing in previously unused space under floors. Some models are self-supporting and others are assembled on frames that sit between the rows of foundations under the house. The polymers used for the bladders are UV, puncture and rodent resistant, and some can be used for drinking quality water.
Another option is rain storage gutters that are designed to collect and store rainwater from the roof.
Tank accessories
There are a range of accessories that are needed to ensure that the water collected in your tank is free from containments, especially debris from your roof and gutters. Gutter guards or special gutters with filters can be used to prevent leaves and debris entering the guttering. An alternative to gutter guards are leaf diverters that are mounted on the downpipe and typically consist of a mesh screen angled to deflect leaves, but that allows water to flow through into the downpipe.
First rain diverters are used to divert the first bit of rain away from the rainwater tank along with any accumulated containments from the roof or guttering.
Getting it into your garden or house
To use rainwater in the garden you can simply run a hose from the tank, but the flow rate will not be very fast. To get similar flow rates to mains water add a pressure pump. In choosing a pump you need to consider the number of taps that are likely to be used at once, the height and distance you need to pump water, the noise of the pump, and the price.
To use rainwater in the house, plumbing connections will need to be made to the pipe network either at an incoming point or at different points of the house. You will need to get a licensed plumber to make these connections and authorised backflow prevention devices will need to be used where connections are made with mains water pipes.
Regulations
State and local government planning and building regulations need to be taken into account before installing a rainwater tank. Heritage or environment overlays may require permits for rainwater tanks on your property, and may limit where you can locate the tanks. Check with your local council to see if there are any regulations regarding rainwater tank installation.
Rebates
There are government incentives in most states that offer a financial rebate for installing a rainwater tank. Click here to see what rebates are available in your state or territory.
More information:
Rainwater rebates
ATA book: Water-Not down the drain
www.yourhome.gov.au
www.greenplumbers.com.au
www.enviroplumber.com.au
