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Water tank sitting in a back garden surrounded but plants.

Overview

Catching rainwater and storing it in a tank is a great way to conserve water for times of drought. With the right plumbing, the stored water can be used for things like watering the garden outside and flushing toilets inside the home.

Here are some things to take into consideration when choosing a water tank.

Safety tip: Always wear the appropriate safety equipment (safety glasses, gloves, ear muffs and a mask, for example) and always follow the instructions for the product or equipment.

Steps

1Determine the tank’s purpose

First, determine what you’ll be using the water tank for. Will you use it primarily outside, to water garden beds and the lawn? Or would you also like to use the water inside – to flush toilets, for example? Would you like to take the usage a step further and use the water to wash clothes or to bathe and shower? (With the right system, it’s possible.)

Once you’ve determined what you’ll be using your water tank for, you can start thinking about the size of the tank you’ll need, where you might want to place it, and how it will need to be plumbed.

Water tank in the back garden

2Work out the size

The size of tank you’ll need is based on how much water you will use and how much you might collect in a season. Work with your plumber to calculate your usage as well as the amount of water you’re likely to collect.

Here’s a rough calculation to follow: Your roof area (in square metres), multiplied by the annual average rainfall (in millimetres) in your area equals the maximum rain harvesting capacity (in litres). This will give you some idea of how much water you might be able to collect and store.

Bunnings team member touching the water tank

3Choose the type of water tank

Once you know the capacity you’ll need, you can start looking at the various storage and placement options.

There are many different types and styles of rainwater tanks – for example, standard corrugated, slimline, below ground and even bladder tank systems that can be hidden under the deck. Each system has its pros and cons, so consider which elements are important to your needs.

Bunnings team member touching the water tank

4Abide by regulations

There are always regulations to consider when adding things to your property and rainwater tanks are no exception.

For example, tanks must be connected to an overflow line so that the tank doesn’t overflow into the neighbour’s yard in times of heavy rainfall or flooding. The tank must also be connected to a solenoid which helps bring water in from the mains if the tank runs dry, which can happen in hot, dry summers. Rainwater tanks must also be signed off by a registered plumber, who will ensure that everything is working safely and correctly.

Bunnings team member reviewing the pipe connected to a water tank

5Watch the full episode

For more renovation inspiration, watch Episode 7: Backyard and Alfresco renovation in our Make It Happen: The House Project series.
Health & Safety

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.