Which term describes the pressure caused by the elevation of a water column?

• A. Head pressure
• B. Normal operating pressure
• C. Residual pressure
• D. Flow pressure

Answer: (A)

When water sits elevated, its weight creates pressure that increases with the height of the column. This hydrostatic pressure is described by the pressure due to height, commonly called head pressure. It reflects the fact that the pressure at a point in a static water column is proportional to the vertical distance to the free surface (p = ρgh). The term “head pressure” captures this idea of pressure generated by the elevation of the water column, independent of any flow or pumping.

The other terms describe different things: normal operating pressure is just the typical pressure range during normal use; residual pressure is the remaining pressure after a pump stops or a system changes state; flow pressure refers to pressure associated with moving fluid or pressure losses during flow.