OffGridFoundry.com
Rainwater Catchment Calculator
Estimate annual collection yield and water self-sufficiency for your off-grid system.
Roof & Collection
Catchment roof area
Roof material
First-flush diverter
US Region & Rainfall
Region
Household Water Needs
Household size
2
Water use mode
Off-grid conservation — 20 gal/p/day
Gallons / Year Collected
—
annual estimated yield
Monthly Breakdown
| Month | Rain | Collected |
|---|---|---|
|
◑
Enter inputs to see monthly breakdown |
||
| Annual collection | — |
| Household need / yr | — |
| Self-sufficiency | — |
| Recommended tank | — |
| Dry spell buffer | — |
Rainwater alone will not cover your annual household needs in this region. Use to offset municipal or trucked water use.
Formula: sq ft × rainfall (in) × 0.6233 × efficiency [− first-flush loss].
Coefficients from Texas A&M AgriLife Extension. NOAA 1991–2020 Climate Normals.
Coefficients from Texas A&M AgriLife Extension. NOAA 1991–2020 Climate Normals.