How Much Rain Collected From Roof

For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain.

How much rain collected from roof.

Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water. If your average rainfall was 25 inches year your annual collection potential is 1 120 x 25 28 000 gallons year. To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above. To find how much rain you can collect in an average rain year multiply this number by the average inches of rain.

That s 600 less gallons you have to pay for and use from your town water supply. Rain barrel supplies list. Rainwater collection calculation formulas and equations roof area ft2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember. So how can you do the math for your own roof.

If you have 1 000 square feet of roof on your house and it rains just 1 inch you can collect 600 gallons of water to be used in your garden for washing your car or just for drop irrigation around your property. Keep in mind most rain falls over 2 3 months of a year. An average suburban roof of 200m 2 with such a rain fall can potentially harvest 100 000l of rainwater 200m 2 500mm 100 000l. It isn t uncommon for an area to collect up to 350mm of rain in just one month even in rural areas.

1 of rain on 1 000 sf roof will yield 623 gallons roof area m2 x precipitation amount mm amount collected liters.