Rainfall Rainwater Calculator

rainfall calculator precipitation table DMV

Source: weatherbase.com

Rainfall Capture: “How much rain can I capture from my roof?”

Well, here is a handy calculator to attempt to answer that question for the general customer. Some situations may vary, for example: You have one downspout that services 90% of your roof and another that serves 10%. In that case just list your house as having one downspout. By no means do you need to capture 100% of the rainfall that travels down the downspout. Most don’t have usage for that volume of water. Our average system install size is 2 barrels (110 Gallons), though one and two barrel rain barrel systems are the most common and larger multi-barrel systems are fairly frequent. Use the map on the bottom if you don’t have an idea of your roof sq footage. Generally speaking, the average rainstorm in the DMV area drops .5″

Hopefully this calculator is useful in helping you determine how large your rain barrel or cistern system can / could / should be. Ultimately, space is an important restriction as well. We have a great deal of experience and can service any customer’s setup be it urban, suburban, or rural.

If you need help determining your roof surface area (it doesn’t need to be exact, just close) try Area calculator provided by Map Developers

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