Are you a homeowner who wants to save some money on your water bill?
Want to install a cistern to collect rain from your roof?
You can perform these calculations to determine an estimate of the total potentially collectable gallons of water
that fall on your roof and in your yard during any given period of time; annual, single day, monsoon season, etc.
The total will generate when you change any You only need to fill out the first

the "bird's eye"
view, slope
doesn't matter
↓		 inches / 12
↓		 Roof: 0.8 ─ 0.95
Bare earth: 0.3 ─ 0.55
Grass: 0.1 ─ 0.25
↓		 rounded to nearest whole gallon
↓
surface area (ft2) rainfall (ft.) runoff coefficient gal/ft3 total (gal)
Roof × × × 7.48 =
Yard × × × 7.48 =
× × × 7.48 =
× × × 7.48 =
☞ ☞
Grand total
Total CCF (total ÷ 748)
Centum Cubic Feet