How Much Rain Water Will Roof Collect

Rainwater collection calculator in gallons.

How much rain water will roof collect.

Untreated rainwater collected from roofs is not safe to drink. An average suburban roof of 200m 2 with such a rain fall can potentially harvest 100 000l of rainwater 200m 2 500mm 100 000l. 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.

Most states have shifted their laws in favor of private rainwater harvesting. 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. 1 of rain on 1 000 sf roof will yield 623 gallons. Take the dimensions of the footprint of your roof and convert them to inches.

Rainwater can be collected from the roofs using the rain water harvesting method. Rainwater collection calculation formulas and equations. The answer is about 623 gallons. Traditionally this involves harvesting the rain from a roof.

Roof area ft2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember. Any container capable of collecting the rain shedding from a roof or patio can be used as a rainwater harvesting system. The rain will collect in gutters that channel the water into downspouts and then into some sort of storage vessel. The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area.

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. For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain. So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall. When you look at the numbers it s surprising how much water you can collect every time it rains.

To calculate the runoff from any given rainfall. To comply with colorado water law the container must be equipped with a sealable lid. To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above. 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.

Rainwater harvesting is collecting the run off from a structure or other impervious surface in order to store it for later use. It isn t uncommon for an area to collect up to 350mm of rain in just one month even in rural areas. Collected rainwater may be used to irrigate outdoor lawns plants or gardens.