Hydraulic Data
To assist you to calculate the size of tank you
require, detailed below are average water
usage and rainfall catchment figures.

Usage:
1 person: 140 litres per day
Family of 4: 450 litres per day

Catchment:
25mm rainfall (1’) provides from:
1 sq. metres (10.7² ft.) 26 litres (5.7 galls.)
10 sq. metres (107² ft.) 260 litres (57 galls.)

Rule of Thumb
For each 1’ of rain, a square foot yields ½ gallon of water