Types of domestic water meters include displacement, multi-jet, and ultrasonic units. Displacement meters are very accurate for low to moderate flow rates. Multi-jet and ultrasonic meters are suitable for both residential and commercial users.
Displacement meters rely on water to physically displace a moving measuring element. A piston or disk moves a magnet that operates the register. Multi-jet meters stream numerous jets of water against an impeller that measures the water velocity through its rotation. Ultrasonic water meters use a transducer that sends sound waves through the water to determine its velocity. Ultrasonic units are very accurate and can measure increments as little as 0.01 gallons.