The main economic activity in the Jiu Valley is mining, which produces valuable mineral raw materials required for the region development and progress, representing the main link in the value producing chain. The majority of mining operations and other economic activities existing within the East Jiu basin produce negative environmental impact (more or less severe), as well as and positive effects such as those related to increasing employment, staff training, creating infrastructure, etc. In most cases, the negative impact of the human activities can be considerably mitigated or even completely eliminated through remedial measures, particularly through the environment rehabilitation in the affected areas. But if a water body is strongly affected by pollutants generated by the human activities, the pollution impact is especially heavy near the water body bottom, with significant negative changes of the aquatic ecosystems and impossibility of consumption and use of the water resources by the riparian population. The main objective of this paper consists in identification and description of all human activities presented within East Jiu basin and analysis of their impact on the river (and other water bodies) water quality. For assessing the East Jiu water quality and monitoring its variations with time, water quality index (WQI) was used, aggregating individual quality indicators (expressed in physical units) into a single unique water quality measure.