Water meters are read in gallons, because the home's storage tank capacity is also measured in gallons in the United States. Capacity or volume is measured in gallons, in accordance with the U.S. customary system.
When water passes through the water meter, the meter's dial will move. One rotation of the dial is equivalent to 7.48 gallons. The water meter normally has an odometer, which gives the reading of the total water usage until then in gallons.
Dedicated water meters for homes show water reading in gallons. A mixed-use meter shows water readings in cubic feet. To convert the cubic feet reading into gallons, the reading should be multiplied by 7.48.