How Much Rain Collected From Roof

That s 600 less gallons you have to pay for and use from your town water supply.

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. When you look at the numbers it s surprising how much water you can collect every time it rains. 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.

It isn t uncommon for an area to collect up to 350mm of rain in just one month even in rural areas. With two inches of rain you can collect around 1 240 gallons. 1 of rain on 1 000 sf roof will yield 623 gallons roof area m2 x precipitation amount mm amount collected liters. Gallons collected per inch of rainfall 0 62 total collecting area of roof in square feet so if you have a 1 000 square foot house you can potentially collect 0 62 1 000 620 gallons of water every time it rains an inch.

So how can you do the math for your own roof. 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. To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above.

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