Rainwater Harvesting Calculator

Estimate your potential water collection and financial savings based on your location and setup.

1. Select Units of Measurement

Metric (m², mm, Liters) Imperial (ft², inches, Gallons)

2. Catchment Area

3. Roof Type Metal / Tile / Slate (90%) Asphalt / Shingle (80%) Green Roof (25%) Gravel (60%)

4. Tank Size

5. Average Monthly Rainfall (mm)

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Financial Savings (Optional)

Cost of Municipal Water

USD ($)EUR (€)GBP (£)

Cost per... 1000 Liters

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Results

Total Annual Collection

Tank Capacity Met

Total Annual Savings

Monthly Breakdown