水压计为一个可透过液体高度或容量来测量液体压力的设备。 它透过的地心引力对液体牵引的特质来计算出液体压力的结果。

使用的过程，透过将水压计的感应头放置在地下水位的某一个定点位置，测量而成。

A piezometer is either a device used to measure liquid pressure in a system by measuring the height to which a column of the liquid rises against gravity, or a device which measures the pressure (more precisely, the piezometric head) of groundwater at a specific point. A piezometer is designed to measure static pressures, and thus differs from a pitot tube by not being pointed into the fluid flow.