NGWA General Drilling Practice Exam

Hydrostatic pressure is the pressure produced by a fluid at rest due to its own weight. In an aquifer, the water exerts this pressure on surrounding materials at a given depth, increasing as you go deeper (p = ρ g h) and acting equally in all directions. This is the standard way to describe the pressure from the water column when there’s no motion involved.

The other terms aren’t used to describe this specific situation: hydraulic pressure is a broader term related to fluid systems and flowing fluids, water table pressure isn’t a standard hydrologic term, and aquifer pressure is vague. When groundwater is moving, we talk about hydraulic head (which combines pressure and elevation), but the pressure component from a static water column is best described as hydrostatic pressure.