Evaluation of a river self-purification capability gives required information for a sustainable management of the river receiving pollutants. The aim of this paper is to investigate the self-power of river to purify water after some distance from the pollutants added in it. The Erai River is the famous river in Chandrapur district because of CSTPS. The water supply department of Chandrapur treated the Erai water and distribute to peoples of city, the river water is directly used by nearest agriculture field due to that some impurities and pollutants is directly or indirectly added in water. Some of vital physico-chemical parameters i.e. temperature, pH, electrical conductivity, total solids, hardness, dissolved oxygen and alkalinity was analyzed in this study. The observations and results shows that the addition of oxygen by naturally in water is maintain the purity and quality of Erai river water.