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.
Runoff produced per square foot of roof.
Multiply the two figures together to obtain the square footage of your roof step 2 determine the percentage of water collected from each downspout p.
The answer is about 623 gallons.
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.
Divide 100 by the number of downspouts in order to obtain the percentage of water collected from each downspout.
Count the number of downspouts coming from your roof.
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.
To calculate the runoff from any given rainfall.
Measure along the length of the house or building and along the width of the house or building in feet.
Measure your house at ground level then add in the roof s overhang for greater accuracy.
0 gallons per minute gpm 0 cubic feet per second cfs peak runoff volume.
So how many square feet of your roof will your pv solar system cover.
Because of the variables pinning down exact numbers is tough.
Step 1 determine the footprint of your structure f in square feet.
However calctool s unit menus remove this issue doing all the unit conversion for you.
Take the dimensions of the footprint of your roof and convert them to inches.
0 gallons 0 cubic feet.
Roof area ft2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember.
This nominal square footage amount is then multiplied by a factor associated with the roof s pitch.
Although this calculation is simple in principle the units can make it a headache.
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 inches per hour data source.
1 of rain on 1 000 sf roof will yield 623 gallons roof area m2 x precipitation amount mm amount collected liters other water conservation calculators.
Roof pitches in.
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.
Use our metric system version.
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.
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.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
Rainfall calculator english units how much water falls during a storm.
