Groundwater is the general term used to describe the water that has permeated into the surface of the earth and formed underground water lakes that are known as aquifers. The level of groundwater is monitored by special measuring instruments within so called monitoring wells. Monitoring wells are wells with a small diameter drilled into the ground, which are used for level monitoring of groundwater and water quality analysis.

Usually you can find few of them few meter far from your underground fuel tanks, in below we have shown few different type of common groundwater monitoring wells.