rainwater capture guide

    Rainwater collection guide - in litres

      The selection of OneWaternaturally rainwater tank can be decided using useful information such as:

        • the size of the roof capture area; and
        • the amount of rainfall in the region.

        This information and calculation has then to be judged against the the frequency of the rainfall and the quantity of the captured rainwater. A calculation can then be estimated for the frequency of the rainfall and the size of the rainwater tank needed to maximise the collection and storage capacity.
        (for example if rain is expected on the capture roof every three weeks then the tank size to store that amount of rainwater can be easily estimated.
        Notwithstanding the larger the storage capacity the better chance of collecting all the scarce rainfall that may occur in seasonal periods for prolonged dry conditions. If the capacity is available the more rainwater can be collected as a resereve supply.)

      The rainfall chart below can be used to estimate a need for rainwater collection and storage
      Rainfall for a Region
House Size Sq. Mtrs. House Size Squares 25mm (1") 50mm (2") 75mm (3") 100mm (4") 150mm (6") 250mm (10") 500mm (20") 750mm (30") 1000mm (40")
36 Dble Garage 900 1800 2700 3600 5400 9000 18000 27000 36000
50 5.4 1250 2500 3750 5000 7500 12500 25000 37500 50000
100 10.8 2500 5000 7500 10000 15000 25000 50000 75000 100000
150 16.2 3750 7500 11250 15000 22500 37500 75000 112500 150000
200 21.5 5000 10000 15000 20000 30000 50000 100000 150000 200000
300 32.3 7500 15000 20000 30000 45000 75000 150000 225000 300000
400 43.1 10000 20000 30000 40000 60000 100000 200000 300000 400000
500 53.8 12500 25000 37500 50000 75000 125000 250000 375000 500000