Gutters and a downspout.
Roof area to gallons.
The runoff for the grass portion of drainage zone a is.
0 35 x 1 5 x 900 96 23 4 91 gpm.
Or 0312 gallons per minute sq.
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.
1 00 x 1 5 x 500 96 23 7 79 gallons per minute.
Converting this to gallons per minute per square foot gpm ft 2.
Rainwater collection calculator in gallons.
The answer is about 623 gallons.
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.
Highly porous concrete roofs may require more coating for proper coverage.
To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above.
Using a 10 000 sq.
Either way you would like to know how much rain has fallen how many gallons have come down from the skies onto your roof yard block or town.
The total rainfall and how rapidly it falls will affect the runoff from the roof.
Roof area ft 2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember.
Roof area the 3 inch rainfall will produce 18 700 gallons in one hour at the rate of 312 gallons per minute.
The runoff q for the roof area in drainage zone a is.
Rainwater can be collected from the roofs using the rain water harvesting method.
One gallon will cover 50 square feet of foam or modified bitumen roofing concrete or bonded tar and gravel roofing.
Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water.
You might even want to know how many baths you could get from your rainstorm.
Rain barrel supplies list.
To a depth of 1 in 1 hour.
1 inch of rainfall in an hour will cover 1 sq ft.
For all three products allow one gallon of roof coating for every 80 square feet of corrugated metal roof or 100 square feet of smooth metal roofing.
The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area.
To calculate the runoff from any given rainfall.
An inch of rain is not much but it if falls in half an hour it could flood a gutter.
1 of rain on 1 000 sf roof will yield 623 gallons roof area m 2 x precipitation amount mm amount collected liters other water conservation calculators.
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.
A roof of 1 200 square feet in size will collect more water than one that is 600 square feet.
Total roof area also affects runoff.
In the form below choose an area s and a rainfall amount to see how many gallons of water fell from the sky onto that area.
