Roof Rainwater Harvesting Calculator
Calculate the amount of water that can be collected from the roof area and rainfall.
m²
mm
%
Result
2.550 litre
Collectable water: 2.550 litres
Result in all units
Step-by-step solution
What Is Rainwater Harvesting?
The rainwater harvesting calculation gives the amount of water that can be collected from a roof surface during a given rainfall. It is used for water saving and irrigation.
How is it calculated?
How Is It Calculated?
Water (L) = roof area (m²) × rainfall (mm) × efficiency
- Enter the roof area and the amount of rainfall.
1 mm of rainfall yields about 1 litre of water from 1 m² of roof.
Frequently Asked Questions
Why is the efficiency less than 1?
Due to evaporation, leakage and gutter losses, the collected water remains a little below the theoretical amount.