Gallons Of Water On Roof
This means that each square foot captures about 62 gallons per inch of rain.
Gallons of water on roof. Required roof drainage flow rate in gallons per minute 0 0104 x rainfall rate x roof area where rainfall rate is expressed in inches per hour and roof area is given in square feet. For every 1 inch of rain and 1 000 square feet of roof you capture about 620 gallons of water. Rainwater collection calculator in gallons. So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain. Simply take your roof s square footage and multiply by 62. If your average rainfall was 25 inches year your annual collection potential is 1 120 x 25 28 000 gallons year. The answer is about 623 gallons.
Converting this to gallons per minute per square foot gpm ft 2. 1 inch of rainfall in an hour will cover 1 sq ft. Roof area m2 x precipitation amount mm amount collected liters. To a depth of 1 in 1 hour.
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. Take the dimensions of the footprint of your roof and convert them to inches. To calculate the runoff from any given rainfall. How much will your roof be able to capture.
The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area. Rainwater can be collected from the roofs using the rain water harvesting method. To find how much rain you can collect in an average rain year multiply this number by the average inches of rain.