A roof of 1 200 square feet in size will collect more water than one that is 600 square feet.
How many gallons of rain water from gutter run off.
Total roof area also affects runoff.
Rain barrel supplies list.
In this example 600 x 240 x 1 144 000 cubic inches of water.
You might even want to know how many baths you could get from your rainstorm.
To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above.
By this math we are able to catch about 656 66 gallons per inch of rain.
In the form below choose an area s and a rainfall amount to see how many gallons of water fell from the sky onto that area.
Gutters and a downspout.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
Take the dimensions of the footprint of your roof and convert them to inches.
Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water.
An inch of rain is not much but it if falls in half an hour it could flood a gutter.
Either way you would like to know how much rain has fallen how many gallons have come down from the skies onto your roof yard block or town.