How Do You Calculate Rainwater Runoff From A Roof?
How Do You Calculate Rainwater Runoff From A Roof? Take the dimensions of the footprint of your roof and convert them to inches. (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