How Much Rain Water Will Roof Collect

The rain will collect in gutters that channel the water into downspouts and then into some sort of storage vessel.

How much rain water will roof collect.

So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall. If your average rainfall was 25 inches year your annual collection potential is 1 120 x 25 28 000 gallons year. Rainwater harvesting is collecting the run off from a structure or other impervious surface in order to store it for later use. To find how much rain you can collect in an average rain year multiply this number by the average inches of rain.

Take the dimensions of the footprint of your roof and convert them to inches. Untreated rainwater collected from roofs is not safe to drink. It isn t uncommon for an area to collect up to 350mm of rain in just one month even in rural areas. Roof area m2 x precipitation amount mm amount collected liters.

The answer is about 623 gallons. For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain. To calculate the runoff from any given rainfall. Rainwater collection calculation formulas and equations.

In this example 600 x 240 x 1 144 000 cubic inches of water divide by 231 to get the number of gallons because 1 gallon 231 cubic inches. When you look at the numbers it s surprising how much water you can collect every time it rains. Rainwater can be collected from the roofs using the rain water harvesting method. Roof area ft2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember.

1 of rain on 1 000 sf roof will yield 623 gallons. Rainwater collection calculator in gallons. Keep in mind most rain falls over 2 3 months of a year. The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area.

To comply with colorado water law the container must be equipped with a sealable lid. 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. 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.

Any container capable of collecting the rain shedding from a roof or patio can be used as a rainwater harvesting system. Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water. Collected rainwater may be used to irrigate outdoor lawns plants or gardens.