In this example 600 x 240 x 1 144 000 cubic inches of water.
Rain fell from a roof.
To find how much rain you can collect in an average rain year multiply this number by the average inches of rain.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
1 place a piece of standard metal drip edge onto a table or between a pair of sawhorses.
For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain.
Take the dimensions of the footprint of your roof and convert them to inches.
Block out distractions to.
It isn t uncommon for an area to collect up to 350mm of rain in just one month even in rural areas.
Keep in mind most rain falls over 2 3 months of a year.
If your average rainfall was 25 inches year your annual collection potential is 1 120 x 25 28 000 gallons year.
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.
You might even want to know how many baths you could get from your rainstorm.
An average suburban roof of 200m 2 with such a rain fall can potentially harvest 100 000l of rainwater 200m 2 500mm 100 000l.
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.