What is a perched water table?

A perched water table is an accumulation of groundwater located above a water table in an unsaturated zone. The groundwater is usually trapped above a soil layer that is impermeable and forms a lens of saturated material in the unsaturated zone.

A perched water table is normally insufficient for the purpose of supplying domestic groundwater requirements and generally runs dry after it has been drilled. If a perched water table intersects a surface that has a slope, it can be manifested by seeps or springs along this line of intersection. The slope of a water table is in general proportional to the slope of the overlying land surface.