This calculation assumes a 90 efficiency.
2000 sqft roof 1inch of rain how much water.
To find how much rain you can collect in an average rain year multiply this number by the average inches of rain.
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.
Either way you would like to know how much rain has fallen how many gallons have come down from the skies onto your roof yard block or town.
Just multiple the square footage of roof space you have available x 0 6 gallons per square foot per inch of rain and you can see how much water you can collect from each inch of rain that falls.
So if you have 2 500 square feet of roof available for water catchment and a single inch of rain falls one day we see that.
To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above.
Or maybe a low pressure cell has been napping overhead and your arm is hurting from holding that umbrella while you watch your basement fill up with water.
Rain barrel supplies list.
Surprisingly a single quarter acre of land in the city can harvest over 100 000 gallons of water annually.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
Even though we live in the arid southwest santa fe receives an average of 14 2 inches over 66 days of rain each year.
Use our metric system version.
Since one inch of rainfall provides approximately 600 gallons of water for a 1 000 square foot catchment area and our theoretical house has a 2 000 square foot catchment area twice the area you will multiply 600 gallons by 2.
Take the dimensions of the footprint of your roof and convert them to inches.
For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain.
When you look at the numbers it s surprising how much water you can collect every time it rains.
36 4 x 46 4 2 000 sq ft your roof catchment area is thus 2 000 square feet.
Rainfall calculator english units how much water falls during a storm.