Rainwater Off Roof Calculator

Rain barrel supplies list.

Rainwater off roof calculator.

Multiply the area of your roof by the amount of rainfall you wish to calculate for. The number of feet multiplied by 144 equals inches. So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall. Gutters and a downspout.

1 500 x 144 216 000 multiply those 216 000 square inches by the rainfall. Then click on the outer points of your roof and a polygon will instantly be created. Column 1 column 1 column 1 column 1. To work out the surface area simply multiply the length in metres by width for square or rectangular roofs.

Since rainwater is collected from rooftops you will need to work out the total surface area of roof s that will be used to catch rainwater. The area measurement will appear right above the map. Need help selecting which tank is right for you. Take the dimensions of the footprint of your roof and convert them to inches.

To calculate the runoff from any given rainfall. Rainwater collection calculator in gallons rainwater can be collected from the roofs using the rain water harvesting method. Roughly speaking 1 millimetre of rain over 1 square metre of roof equals 1 litre of water. Use our water catchment and water usage calculators below to make your selection easier.

Use the zoom tool in the lower right hand corner of the map to get closer so you can see draw on your roof. To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above. Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water. It is the middle of july in georgia and both you and your tomatoes are wilting in your yard both looking to the sky and hoping for rain.

Rainfall calculator english units how much water falls during a storm. Annual rainfall in millimetres x roof surface area in square metres roof catchment capacity. The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area. Water catchment calculator how much rainwater can you harvest.

Once you have the square footage number enter it into the rainwater collection calculator above. Although this calculation is simple in principle the units can make it a headache. For example if you have a roof that measures 1 500 square feet that equals 216 000 square inches. Use our metric system version.

The catchment areais multiplied by the depth of rain that falls on it to give the total volumeof waterproduced. If you don t already have rain gutters on your house this one time investment is the biggest cost you ll face. This capacity can be calculated using the following formula.