Serious damage occurs in the foundation of buildings because of the effect of the circumstances surrounding. Waste water seeped to the soil plays an active part in the change of these circumstances. The paper presents an experimental study to investigate the influence of waste water on the chemical properties, clay mineralogy, cation exchange capacity and surface area of fine-grained soils. For purpose of study, five samples of fine-grained soil were mixed with 0, 25, 50, 75 and 100 percent of waste water. Physico-chemical properties such as pH value, organic matter, cation exchange capacity and total element composition were determined. The clay minerals were evaluated by x-ray diffraction analysis. Test results show that montmorillonite content, organic matter, cation exchange capacity and total element compositions were determined. Test results show that montmorillonite content, organic matter content, cation exchange capacity, sulphates, chlorides, and surface area of clayey soil increase with increase the amount of waste water in Egyptian fine-grained soils.