 In the United States most utilities bill only to the nearest 100 or 1,000 gallons (10 to 100 ft.3, 1 to 10 m3), and often only read the leftmost 4 or 5 numbers on the display wheels.Using the above example, they would read and bill 1,234, rounding to 1,234,000 gallons based on a 1,000-gallon billing resolution.The most common rounding for a particular size meter is often indicated by differently coloured number wheels, the ones ignored being black, and the ones used for billing being white.