Gutters and downspouts the gutters and downspouts take the rainwater down to your cistern.
How many gallons of rain water from gutter run off.
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.
Total roof area also affects runoff.
An inch of rain is not much but it if falls in half an hour it could flood a gutter.
Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water.
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.
You might even want to know how many baths you could get from your rainstorm.
The answer is about 623 gallons.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
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.