The fundamental bases of urban groundwater investigation are urban hydrogeological studies using empirical datasets derived from valid geotechnical, hydraulic, and geophysical tests, on real information about urban infrastructure elements, as well as on theoretical calculations and modeling. The examination of urban underground conditions and groundwater behavior is based on geology and mechanics of both natural and anthropogenic soils. In investigations, subsurface materials are described in terms of intrinsic physical properties (moisture, density, specific gravity, porosity, permeability, others) and of hydrologic behavior that are used to determine responses under given groundwater and surface water conditions. Urban groundwater studies are concerned with the effects of various urban structures such as deep foundations, caves, storages, shelters, piles, and boundary walls for which groundwater flow and properties can be explained and predicted.