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Garden and Landscaping

Rainwater tanks

Rainwater tanks are used to collect and store rainwater runoff typically from rooftops. Rainwater tanks are installed to store rainwater for later use and to reduce the mains water use for economic and environmental reasons.

Stored water may be used for watering gardens, agriculture, flushing toilets, in washing machines and to wash cars. Below are three main reasons why rainwater tanks are very useful;

  • Save Money: As the cost of living seems to be increasing day by day, many Australians are turning to rainwater tanks to reduce their water bill. Rainwater tanks can reduce the average household bill significantly as you can replace approximately 40% to 50% of mains supply water with rainwater.
  • Environmental Reason: As climate change becomes more evident, many Australians are turning to natural water sources to reduce their footprint on the earth. Rainwater contains excellent nutrients for gardening and is not treated with any harsh chemicals.
  • Emergencies: As Australia is prone to incredibly hot and dry summers, rainwater tanks can provide peace of mind for many that live in high fire-damage areas. Throughout the year, your rainwater tank collects water that can be used to help fight bush fires and protect your property.

When thinking about installing a rainwater tank it is important to identify what size tank is needed for your house. You can do this by investigating the following;

  • How much rainfall does your area receive on average? This can be found on The Bureau of Meteorology website at www.bom.gov.au
  • What is the area of your roof, in particular the catchment surface? Visit www.rainharvesting.com.au/rainwater-knowledge-centre to find out how to calculate the catchment surface of your roof
  • How much rainwater do you expect will be used daily?
  • Where do you intend to put the rainwater tank and how much space do you have?

The following formula can be used to calculate the appropriate size rainwater tank for your household;

Roof Area x Annual Rainfall

= Maximum Available for Capture

You then need to calculate the storage volume;

Most Days without Rain x Average Daily Water Use

= Storage Volume Required on Day One of a Dry Spell

With the growing water restrictions in Perth, by properly installing an appropriate rainwater tank for your house you will be doing your bit for the environment and for the next generation.