Ground water surveys are one of the largest applications of the GPR, because it is a rapid way obtaining information, of even a large area, in regard to identifying ground water appearances.

Coarse sand- and gravel formations and coarse moraines are the most significant ground water formation areas. In these areas the GPR is usable. The ground water attempts to settle in water conducting material almost in a horizontal level. Because of this we can, as a rule of thumb, determine that, in the GPR profile the ground water level is visible as a mirror image of the ground surface topograhy. For the same reason the ground water does not follow possible layer structures visible in the GPR profile, but cuts them. These two facts are the most important criteria when identifying the level of ground water on the GPR profile.