Total roof area also affects runoff.
How many gallons of rain water from gutter run off.
The answer is about 623 gallons.
Gutters and downspouts the gutters and downspouts take the rainwater down to your cistern.
Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
In this example 600 x 240 x 1 144 000 cubic inches of water.
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.
Take the dimensions of the footprint of your roof and convert them to inches.
To calculate the runoff from any given rainfall.
To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above.
Gutters and a downspout.
Rain barrel supplies list.
A roof of 1 200 square feet in size will collect more water than one that is 600 square feet.
You might even want to know how many baths you could get from your rainstorm.