Domestic wastewater contains many injurious chemical compositions and dissolved salts. Its pollution of soil was noticed in various residential districts. This resulted from seepage of wastewater into soil, for a long period of time according to: (a) collecting and storage of wastewater in permeable underground tanks, and (b) damage of sewerage networks (pipes and manholes). Permeable underground wastewater tanks were used to collect and discharge domestic wastewater from dewelling buildings in Tanta city, Sohage Governorate, which were constructed in 1980. At foundation depth, the soil engineering properties were determined and studied for different exposure period of wastewater and variant distance from the pollution source. Results indicated harmful effects on physical properties of clayey soil. Moreover, triaxial compression tests were carried out. Its results showed considerable effects on shear strength parameters.