Take a guess what is the volume of water that runs off a 1 000 square foot roof during a 1 rain storm.
Gallons per square foot of roof.
Or 0312 gallons per minute sq.
1 inch of rainfall in an hour will cover 1 sq ft.
Of water 231 sq in.
Where rainfall rate is expressed in inches per hour and roof area is given in square feet.
Take the dimensions of the footprint of your roof and convert them to inches.
The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area.
Of water in a gallon 0 623 gallons per hour.
Rainwater can be collected from the roofs using the rain water harvesting method.
To a depth of 1 in 1 hour.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
Roof area the 3 inch rainfall will produce 18 700 gallons in one hour at the rate of 312 gallons per minute.
To calculate the runoff from any given rainfall.
Max area of roof draining to one down.
For example a 3 inch per hour rainfall will build up to a 3 inch depth on a flat roof in one hour at the rate of 1 87 gallons per hour sq.
Roof area square feet per linear ft of gutter underneath.
Converting this to gallons per minute per square foot gpm ft 2.
Sq ft safe for maximum rainfall reduce by 10 per 90 degree turn.
4 ft 2.
Up to 6 12 7 12 8 12.
1 us gallon 231 cubic inches.
Using a 10 000 sq.