How much rain does it take to fill up our rain barrel? A quarter inch should do it.
The rain barrel is installed at the rear corner of our house. The downspout that drains into it comes from the gutter that drains the house’s largest section of roof. Referring to the survey diagram, the area of that section is 26′ × 15′, or 390 ft². Our rain barrel has an advertised capacity of 48 gal, or 6.4 ft³.
6.4 ft³ equals 390 ft² covered to a depth of 0.0165 ft, or 0.2″. Not all of the rain that comes down the downspout is diverted into the rain barrel, because of the way the diverter is designed to pass excess water through once the barrel is full. So, we can pad the 0.2″ figure a little and just call it a quarter inch of rainfall. And now we know.
