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.

How much rain water will roof collect.

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. Roof area ft2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember. Keep in mind most rain falls over 2 3 months of a year.

Rainwater harvesting is collecting the run off from a structure or other impervious surface in order to store it for later use. Colorado the state with arguably the strictest rainwater harvesting laws passed a bill in 2016 allowing for the collection of rainwater with a 110 gallon maximum capacity. Rainwater collection calculation formulas and equations. It isn t uncommon for an area to collect up to 350mm of rain in just one month even in rural areas.

For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain. Rainwater collection calculator in gallons. When you look at the numbers it s surprising how much water you can collect every time it rains. 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.

An average suburban roof of 200m 2 with such a rain fall can potentially harvest 100 000l of rainwater 200m 2 500mm 100 000l. The rain will collect in gutters that channel the water into downspouts and then into some sort of storage vessel. 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. Most states have shifted their laws in favor of private rainwater harvesting.

The answer is about 623 gallons. To find how much rain you can collect in an average rain year multiply this number by the average inches of rain. To comply with colorado water law the container must be equipped with a sealable lid. 1 of rain on 1 000 sf roof will yield 623 gallons.

Untreated rainwater collected from roofs is not safe to drink. Traditionally this involves harvesting the rain from a roof. To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above. To calculate the runoff from any given rainfall.

If your average rainfall was 25 inches year your annual collection potential is 1 120 x 25 28 000 gallons year. The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area. Roof area m2 x precipitation amount mm amount collected liters.