Free Engineering Tool
Rainwater Harvesting & Recharge Calculator
Accurately determine annual harvest volume, equipment sizing (Rainy FL-80 to FL-500), and groundwater aquifer recharge capability for your site.
Catchment Sizing Parameters
sq.m
20 sq.m
1,000 sq.m
5,000 sq.m
10,000+ sq.m
Live Harvest Sizing Report
Annual Rainwater Harvest Potential
7,90,500 Liters / Year
790.5 m³ Volume
Recommended Filtration Equipment
Rainy FL-500 (2 Units in Parallel) + V-Wire Injection Well
Food-grade SS-304 mesh (250 microns), dual-intensity centrifugal self-cleaning, 100% gravity operated.
Projected Annual Financial Value
₹ 63,240 / Year
Replaces expensive commercial water tanker deliveries and municipal industrial charges.
Formula:
Harvest (L) = Area (m²) × Rainfall (mm) × Runoff Coeff. In accordance with Central Ground Water Board (CGWB) norms.
Methodology
How Rainwater Harvesting Potential Is Calculated
Standard Scientific Formulation
The total volume of rainwater harvested depends on three critical parameters defined by hydrogeologists:
Total Harvest (Liters) = Catchment Area (m²) × Mean Annual Rainfall (mm) × Runoff Coefficient
- 1. Catchment Area: The horizontal projection area of the roof, shed, paved parking, or landscape in square meters.
- 2. Annual Rainfall: The long-term meteorological average annual rainfall recorded by IMD for the specific region.
- 3. Runoff Coefficient: Accounts for evaporation, surface retention, and absorption losses (0.85–0.90 for smooth metal/RCC, 0.70 for paved roads, 0.50 for soil).