This paper discusses the effect of domestic wastewater-seeping on mineralogical and physico-chemical properties of fine soil. Naturally polluted soil samples were taken over a period of time from tested holes of a ground area beside permeable underground wastewater tanks. These tanks are used to collect, store and discharge domestic wastewater from dewelling buildings in Tahta city, Sohage Governorate, which were constructed in 1980. A series of mineralological and physico-chemical analysis was carried out for natural soil samples at different effect-period of wastewater and at variant circle-effect radius (R) from pollution source. The results show significant and harmful effects of domestic wastewater seepage on mineralogical and chemical properties of fine soil. It was found that the wastewater seepage causes sever changes to soil properties depending upon: (a) the expose period of wastewater, and (b) the distance from the pollution source of wastewater.