The answer is about 623 gallons.
Runoff produced per square foot of roof.
If you get about 10 inches of rain over the course of the spring and summer an average 1 360 square foot roof would yield 8 160 gallons of rainwater.
This nominal square footage amount is then multiplied by a factor associated with the roof s pitch.
0 inches per hour data source.
Although this calculation is simple in principle the units can make it a headache.
Use our metric system version.
Roof area ft2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember.
The basic calculation is a x r 231 g where a is the area of your roof in square feet r is the amount of rain in inches and g is the amount of runoff in gallons.
It is the middle of july in georgia and both you and your tomatoes are wilting in your yard both looking to the sky and hoping for rain.
Step 1 determine the footprint of your structure f in square feet.
0 gallons per minute gpm 0 cubic feet per second cfs peak runoff volume.
In this example 600 x 240 x 1 144 000 cubic inches of water divide by 231 to get the number of gallons because 1 gallon 231 cubic inches.
Measure your house at ground level then add in the roof s overhang for greater accuracy.
Divide 100 by the number of downspouts in order to obtain the percentage of water collected from each downspout.
Measure along the length of the house or building and along the width of the house or building in feet.
However calctool s unit menus remove this issue doing all the unit conversion for you.
To calculate the runoff from any given rainfall.
Because of the variables pinning down exact numbers is tough.
Take the dimensions of the footprint of your roof and convert them to inches.
Here you can easily find how much rainwater you can collect from you roof how much you need to remove from a courtyard or how much runoff you can expect from an area of land.
Rainfall calculator english units how much water falls during a storm.
Count the number of downspouts coming from your roof.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
You have to admit that whether you re in a drought situation or not it s hard to pass up that much of a free thing.
Roof pitches in.
Drainage pipe required minimum diameter.
So how many square feet of your roof will your pv solar system cover.
But at 20 watts per square foot a system rated to produce 2 kilowatts would cover roughly 150 square feet while a 3kw system would take up about 225 square feet.
0 gallons 0 cubic feet.
As an example if your overhang is 12 inches you ll add 2 feet to the overall length and 2 feet to the overall width of the house.
