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How Much Water is One Inch of Rain?

Rainfall and Raindrops

Photo by Free-Photos, from Pixabay.com.

According to the U.S. Geological Survey, one inch of rain equals 27,154 gallons of water per acre or 17.38 million gallons per square mile. That breaks down to 5.61 gallons per square yard.

Since the square footage of a median home in Los Angeles County, in December 2023, was 1,763 square feet, that means that one inch of rain falling onto the roof of a median-sized home in the county would equate to 1,098 gallons of water.

Source: U.S. Geological Survey

Also see: Current Rainfall, Month & Season To-Date, Downtown Los Angeles