What negative effect may occur on a service due to a water meter?

• A. Pressure drop
• B. Head loss
• C. Flow reversal
• D. Thermal expansion

Answer: (B)

A water meter creates resistance to flow, turning part of the moving water’s energy into friction and turbulence as it passes through. That energy loss reduces the pressure energy available downstream, so the service experiences lower pressure. In hydraulic terms, this reduction is called head loss—the energy that’s dissipated as water moves through the meter. You might hear about a downstream pressure drop, but head loss is the precise way to describe the meter’s effect on the flowing water. Flow reversal would require backflow conditions beyond a simple meter, and thermal expansion relates to temperature effects rather than the hydraulic energy loss caused by the meter.