The Quaternary sediments in the Nile Delta comprise one of the most important aquifer in Egypt . It was discriminated into two hydrogeological units; the upper unit is the Holocene aquitard and the lower one is the Pleistocene aquifer.

During the last few years, it was noticed that, subsoil water and groundwater of the Holocene aquitard appears at ground surface affecting building and giving rise to building defects which require expensive repair. Salt weathering process is the main factor for building defects ( swelling, distruction, discoloration and exfoliation scale on the building foundation). This study discusses the general reasons for this problem and its impact on building and structures, as well as the corrosion phenomenon affects the pipes of water wells.

The hydrochemical composition of water is the main cause for this corrosion phenomenon, due to chemical reactions of its component with concrete and reinforced steel. The corrosion rate was determined for the reinforced steel and the pipes of water wells using the weight loss experiments. It was found that, it increases with increasing the concentrations of sulfate and chloride anions and pH value. Moreover, the environmental conditions and the material used in construction are other factors for the enhancement of the corrosion process.