Population growth is now causing increasing pressure on the environment. In view of the consequences that flow from it, the safeguarding and protection of ecosystems is a fundamental necessity for the biodiversity of fish species. At the scale of the Sô watershed and its tributary stream, anthropogenic actions have considerably influenced the quality of the available water resources. The purpose of this study is to assess the state of vulnerability of the water resource. From the physicochemical and bacteriological data of the water taken from three points of the outlet of the basin, various forms of water pollution have been proved. The results showed a strong variation of physicochemical parameters, a seasonal dynamics of pollution and differentiated mineralization processes. With high photosynthetic activity in the river, a high concentration of dissolved oxygen, COD, nitrates, nitrites, ammonium and other ions is observed in the dry season. The observed presence of coliforms and streptococci confirmed the state of organic pollution and bacteriological and toxicological risks at the basin scale. This situation now calls on the authorities at various levels and managers of the basins to take the necessary measures to avoid public health problems to the neighboring populations, this situation has an impact on the current development of the locality.