How to use it
- Enter roof catchment area and unit.
- Enter rainfall and a coefficient between zero and one.
- Calculate potential volume.
Rainwater Harvesting Calculator
Estimate potential roof runoff using a user-entered catchment area and coefficient.
About the Rainwater Harvesting Calculator
Estimate theoretical collected runoff for one rainfall amount.
Formula
Collected volume equals area in square meters times rainfall depth in meters times runoff coefficient.
Example
A 100 m² roof, 50 mm rainfall and 0.8 coefficient estimates 4 m³ or 4,000 liters.
Notes
Overflow, first flush, leakage, storage capacity, water quality and local requirements are not included.