Water meters measure the amount of water that flows from the water main into each home.
The meter is a straight reading register, and is read in the same way the mileage is read on an automobile speedometer. Water meters are read once each month for billing. Subtracting last month's reading from this month's figures, gives us the total gallons of water that went through the meter and into the home during the month. They have that notion because they haven't stopped to think about it. You can also get water free from a river or lake, but you have to go to the river or lake to get the water and bring it back.