A frequent question into the 13 News Weather Authority is how much rain is an inch of rain.
When we say Norfolk received an inch of rain, this implies that Norfolk (at the airport) had enough rain to cover the ground an inch deep. Since rain is absorbed by the ground and runs off, this is a "perfect world" answer.
Maybe this will give a better idea of how much rain is an inch of rain.
First, 1 inch of rain implies water one inch deep per surface area. So:
1 inch of rain equals 5.61 gallons per square yard.
1 inch of rain equals 27,150 gallons per acre.
1 inch of rain equals 17.37 million gallons of water per square mile.