DASLab / 09
Rainwater Harvesting
Roof catchment, tank sizing, and yearly yield from local rainfall.
Experimental tool — evolving and open to suggestions: info@derzawi.com
Recommended tank
5 m³
Meets 55% of demand · yearly yield 58.3 m³ vs demand 105.9 m³ (55%)
Bars: monthly harvest (m³). Dashed: monthly demand (m³).
Tank size vs. reliability
1 m³11%
2 m³23%
3 m³34%
5 m³ ← recommended55%
7.5 m³55%
10 m³55%
15 m³55%
20 m³55%
30 m³55%
50 m³55%
75 m³55%
100 m³55%
Monthly yield-after-spillage model on an average year. Real rainfall varies year to year; size up for dry years and check drinking-water treatment rules.