This rainwater harvesting reference table shows the water harvested for a range of roof catchment area values, assuming a rainfall of 50 mm and a runoff coefficient of 0.85. Every figure is computed with the same engine that powers our Rainwater Harvesting Calculator, so the numbers are exact.
| Roof catchment area | Water harvested |
|---|---|
| 25 m² | 1,063 |
| 50 m² | 2,125 |
| 75 m² | 3,188 |
| 100 m² | 4,250 |
| 150 m² | 6,375 |
| 200 m² | 8,500 |
| 300 m² | 12,750 |
| 500 m² | 21,250 |
| 700 m² | 29,750 |
| 1,000 m² | 42,500 |
How to use this table
Find the row closest to your roof catchment area and read across to the water harvested. For a value between two rows, the real figure sits between them — or enter your exact numbers in the Rainwater Harvesting Calculator for a precise answer.
Need a value that is not in the table? — the Rainwater Harvesting Calculator does it instantly, for free, with the formula and a worked example built in.
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