ADEQ Water Distribution Grade 1 Certification Practice Exam 2026 – Your All-in-One Guide to Success!

Flow meters are grouped by how they capture and measure the volume of water, not just by the sensing technology or the display format. The three main classifications are Positive Displacement, Velocity, and Compound. Positive Displacement meters measure a fixed volume per cycle by trapping and counting discrete volumes as they move through the meter. Velocity meters infer flow rate from how fast water moves through a known bore, often using a turbine or similar rotor. Compound meters combine both methods, using positive displacement at low flows and velocity measurement at higher flows to cover a wide range efficiently.

The option listing Compound, Displacement, and Velocity matches these three categories directly, with Displacement representing Positive Displacement. The other options mix different ideas—electromagnetic and ultrasonic refer to sensing principles, turbine/rotary/orifice are specific meter designs or components, and digital/analog/hybrid describe output formats—none of which define the primary classification of water meters.