Water tank calculator

How much water do you use? Use our helpful calculator to find out.

Water Tank Calculator


Activity Times Per Day Activity Ltr Per Day Ltr Per Year
Shower 15 Litres per minute
Bath 150 Litres
Dishwasher 30 Litres per load
Front Load Washing Machine 80 Litres per load
Top Load Washing Machine 100 Litres per load
Brushing Teeth with tap running 5 Litres per person
Drinking, Cleaning, Cooking per person 10 Litres per day, per person
Hand Basin Use 5 Litres per time
Toilet Flush single 6 Litres per time
Toilet Flush half 3 Litres per time


Activity Times Per Day Units Ltr Per Day Ltr Per Year
Garden Sprinkler Garden hose 15L /min.
Car Wash 200 Litres
Hosing Hard Surfaces 15 litres per minute
Drip System litres per hour
Filling pool Size in Litres

Size of water tank

Roof area (m3) Average Annual Rainfall (mm) Amount of rain harvested (litres) Minimum Tank Size
      Assume the tank can fill 3 times
per year (Depends on rainfall and usage patterns)

Total Per Annum

Calculation Summary

Litres per day Litres per year Rain harvested Tank Size


To help calculate the size of water tank you need, Bushmans has created a tank calculator that allows you to input your water usage details and find the right tank for you.

To view the range of Bushmans Tanks available for purchase, please click here