Rainwater Harvesting Calculator
Calculate how much rainwater you can collect and how much you could save. Determine collection potential based on roof area, rainfall, and water usage patterns.
Step 1: Roof & Rainfall
Understanding Collection Efficiency
Collection efficiency represents the percentage of rainwater that can be collected from your roof. Metal roofs typically have the highest efficiency, while green roofs have lower collection rates.
Step 2: Usage & Savings
About Rainwater Harvesting
Rainwater harvesting can reduce your water bills by 30-50% depending on usage. Collected water is perfect for gardening, toilet flushing, laundry, and with proper treatment, even drinking water.
Rainwater Collection Results
Annual Water Collection
Roof Type Collection Comparison
| Roof Type | Efficiency | Annual Collection | Annual Savings |
|---|
Monthly Collection Breakdown
Collection Formula
Annual Collection = Roof Area × Rainfall × Collection Efficiency
To calculate rainwater collection: Multiply roof area (m²) by annual rainfall (mm) and collection efficiency (%). Divide by 1000 to convert to liters (since 1mm rain on 1m² = 1 liter).
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