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## How do you calculate rainfall on a roof?

Roughly speaking, 1 millimetre of rain over 1 square metre of roof equals 1 litre of water. This capacity can be calculated using the following formula: Annual rainfall (in millimetres) x Roof surface area (in square metres) = Roof catchment capacity.

## How much water is in a roof?

Every square foot of roof space collects . 6 gallons of water in a 1 inch rainfall.

## How do you calculate rainwater volume?

Formula: Area (Length x Width) x Rainfall

You must know the approximate dimensions of the water collection surface, most commonly a roof. A typical roof area can provide surprising amounts of water. For example, one inch of rainfall on a roof that is 20 feet by 20 feet can provide 220 gallons of rainwater.

## How much is 1 inch of rain in gallons?

Volume and weight

One inch of rain falling on 1 acre of ground is equal to about 27,154 gallons and weighs about 113 tons. An inch of snow falling evenly on 1 acre of ground is equivalent to about 2,715 gallons of water.

## How do you calculate water usage?

Meters record how much water has been used. Deducting the current meter reading from the previous reading will tell you how many units of water you have used since your last meter reading. To determine your dollar amount of water consumption, multiply the units used by your current water rate.

## How many Litres is 1mm of rain?

With a rainfall of 1 mm, every square metre receives 1 litre of rain water. A rainfall of 1 mm supplies 0.001 m^{3}, or 1 litre of water to each square metre of the field.

## How do you calculate rainfall per area?

Find the average volume of rain = Depth x radius x radius x 3.14. Find the area at the top of the bucket (this is the area over which the rain is collected). Divide the rainfall volume by this area to get the rainfall.

## How do you figure gallons per square foot?

How to Calculate Gallons of Water Per Square Feet

- Measure the depth of the structure in which the water is located. …
- Multiply the depth in feet times the width and length of the pool (square footage) to find the cubic feet. …
- Multiply the cubic feet by the amount of water per cubic foot, which is 7.48 gallons.

## How much water can I harvest from my roof?

Approximately 550 gallons of rainwater can be collected for every 1000 square feet of collection surface per inch of rain. To estimate amount collected in one year, take the square footage of your collection surface, divide by 1000, multiply by 550 and then multiply by the average annual rainfall for your area.

## How much water is in an inch of rain?

Rainfall amount is described as the depth of water reaching the ground, typically in inches or millimeters (25 mm equals one inch). An inch of rain is exactly that, water that is one inch deep. One inch of rainfall equals 4.7 gallons of water per square yard or 22,650 gallons of water per acre!

## How do you calculate the area of a roof?

To find your roof’s total square footage:

- Measure the length and width of each plane on the roof (including dormers) then multiply length times width.
- Add the square footage of each of the planes together.

## How many inch are in a gallon of water?

One US gallon is 231 cubic inches.

## How many gallons of water are in an inch?

To begin, . 62 gallons of water makes up 1 inch in a square foot.

## How many gallons of water is in a rainstorm?

One inch of rain falling over one square mile will result in 17,378,560 gallons!