Why Do You Need A Rainwater Tank?

Why do you need a rainwater tank?

A rainwater tank can reduce harm to our waterways caused by too much stormwater. Tank water collected in rainwater tanks can be used to flush toilets, wash clothes, water gardens and wash cars which is great for the world we live in and will save you money!

Additionally, South Australian building rules require that new dwellings and some extensions or alterations, have an additional water supply to supplement mains water.

The most common way to meet the additional water supply requirement is to install plumbed minimum-sized rainwater tank.

Advantages of rainwater tanks are that they:

  • minimise water usage when used in the toilet, laundry or garden
  • reduce strain on the stormwater drainage system
  • retain water close to source
  • reduce site run-off and flood peaks
  • save you money on water bills

How to choose a rainwater tank that suits your needs.

When deciding the best size for your rainwater tank consider:

  • Applications — maximising the uses of rainwater will help you get the best value from your rainwater tank
  • average amount of water consumed by these applications— speaking to a professional can help you determine this information
  • local rainfall pattern— find the annual rainfall in your area on bom.gov.au — in areas with highly variable rainfall, bigger tanks may be required for the same supply of rainwater
  • area of roof draining to the tank— 1mm of rainfall on 1m2 of roof area = 1L of rainwater
  • aesthetics – colours, material, shapes, location
Approximate tank sizes for a four person household with mains water and evenly spread rainfall:
Use Target volume (L)
Toilet flushing and use on a small garden 2,000–3,000
Toilet flushing, clothes washing and small garden 3,000–5,000
Whole of house water supply 5,000–20,000


Rainwater tanks don’t have to be expensive, Newtons Building and Landscape stock a range of affordable and cheap rainwater tanks that won’t break the bank. There is a tank option for all budgets including cheap rainwater tanks and top end tanks. Some of the different types available are;

Round, above-ground rainwater tanks.

Usually the cheapest type of prefabricated tank per litre of volume. However, in recent years a range of innovative systems has been developed to provide rainwater storage capacity where space is limited.

Slimline tanks

May be installed along a fence line or at the side of your house (check local government planning regulations). They usually need a properly formed concrete slab for support, depending how tall they are relative to their width. Slimline tanks installed along a wall can save space while saving water.

Underground tanks

Save on space and usually have greater catchment potential than above-ground tanks. However, this option requires excavation and if the water is to be used inside the house, the Plumbing Code of Australia also requires that a testable backflow prevention device is fitted on any mains water supply to the house and tested annually. Underground tanks can capture all runoff water and save space.

Rainwater tank pump systems

Pressure pumps are required to deliver water at or near mains pressure, to make full use of your rainwater. Rainwater pumps can be submersible or free-standing. Be sure to select a pump that delivers the expected flow rate while maintaining enough pressure at the most critical water supply point. Ask a professional to help you obtain the right information to determine which pump you will need.

Submersible Pumps

A submersible pump in the rainwater tank can saves space but a major advantage to submersible pumps are that they are very quiet since the water absorbs the noise. They are also more efficient since they don’t need a lot energy sucking in the water that they are submerged within.

Free-Standing Pumps

While a free-standing pump is often cheaper and available in a greater range of pumping capacities, it will require a weather protected spot near the tank and a pump cover.

Newtons Building and Landscape Supplies have a professional and dedicated expert team to assist you in making an informed decision for your rainwater tank and pump. We’re open 7 days and have a range of tanks and pumps in stock and on display in store. We welcome special orders in the case that we do not stock a rainwater tank or pump that meets your requirements. Call 8415 7777 today for a free quote.