© 2006 raintec - all rights reserved, raintec rainwater harvesting systems
privacy policy
To determine the size of tank you require you will need to know the following:
The chart shows average water usage for common activities around the house.
Calculate the total water usage (per person) and multiply it by the number of people using the water source to calculate the total daily water requirement.
Average Water Usage |
|
| Bathroom | |
| "Old Style" shower rose | 20 litres/minute |
| Water efficient shower rose | 9 litres/minute |
| Brushing Teeth(tap running) | 5 litres/minute |
| Washing Hands | 5 litres/minute |
| Shaving | 8 litres/minute |
| Bath (1/2 to 3/4 full) | 150 litres/bath |
| Drips (slow leak) | 22 litres/day |
| "Old Style" single flush toilet | 11 litres |
| Dual flush toilet - Full flush | 6 litres |
| Dual flush toilet - Half flush | 3 litres |
| Laundry | |
| Front loading washing machine | <100 litres/load |
| Top loading washing machine | >100 litres/load |
| Kitchen | |
| Dishwasher | 20-35 litres/load |
| Dishwashing by hand | 18 litres/sink |
| Drinking, cooking and cleaning | 8 litres/day |
| Outside | |
| Garden Hose | 10-20 litres/minute |
| Washing the car | 100-300 litres/wash |
| Watering the garden | 400 litres/day |
To calculate your rainwater harvesting capacity multiply your roof area in metres(horizontal area) by the average rainfall in mm in your area.
For example: 250mm of rainfall over a 36 square metre shed = 9,000L
This is a simplified method of calculating the size of tank you may require.
Other factors to consider are how dependable the rainfall is, and whether there is a backup water supply.
Whether you are considering an above ground or underground tank, you should ensure there is sufficient access for installation and maintenance.
Also consider the aesthetic appearance of the resulting installation.
The water harvested is non-potable for human drinking purposes. further filters can be added to bring the quality of the water to a higher level.