There are a few main things to think about when first looking into purchasing a water tank. These should include at a minimum: –

  • Average annual rainfall in your area
  • Rainwater collection area, whether this is a house, patio or shed roof
  • Family size and usage
  • Land size

Where the rainwater tank will be located: –

  • Closer to your house or shed is usually best – this will make collection easier and reduce plumbing costs
  • Power will need to be run to your pump so this needs to be considered during the initial planning stages
  • If you are using gravity to feed your end usage, then the higher the tank the more pressure at the end usage point
  • In hotter climates it may be necessary to have the sunny side of your rainwater tank in the shade. This can stop bacterial growth and evaporation

Rainwater tanks can be put into the following categories: –

  • Small rainwater tank less than 2,000 litres
  • Medium rainwater tank 2,000 liters to 10,000 litres
  • Large rainwater tank greater than 10,000 litres

Different types of rainwater tanks: –

  • Metal – used above ground and vary in size up to a whopping 700,000 litres
  • Concrete – these can be used above and below ground, and range in size up to around 120,000 litres
  • Polyethylene – these can be used above and below ground and a typical larger rainwater tank can be around 50,000 litres
  • Underground – used in high density living where space is limited. These can either be Polyethylene or concrete rainwater tanks
  • Bladder – used where houses are on stumps or under a raised decking – maintenance on these rainwater tanks can be tricky

Cost

  • Metal Around $16,000 for 160,000 litres
  • Concrete Around $20,000 for 20,000 litres
  • Polyethylene Around $7,000 for 50,000 litres
  • Bladder Around $1500 for 5000 litres

Conclusion

In most circumstance, the type of water tank that you choose will be made, after you have taken your personal circumstances and needs into consideration. Most tanks will have an estimated lifespan of at least 20 years, so whatever rainwater tank you choose, make sure your warranty covers this. Depending on the type of tank you decide on, it can be a large initial cost, some states however do offer rebates, so this is something to investigate.