Peru is a country with a lot of mining activities; however, these activities have a bad reputation due to pollution water. Therefore, the objective of this study is to determine the water quality of the Alto Huallaga watershed, Peru, due to the presence of nearby mining companies and urban populations. To this end, the research question is as follows: Do mining companies pollute the Alto Huallaga River more than urban populations? The research question is answered through the Grey Clustering methodology, which is based on grey systems, using information known from the National Water Authority (ANA). The main purpose of this work is to compare the quality of water that has been influenced by contaminants from mining and non-mining activities. The results obtained in this work show that the environmental management of the mining companies close to the rivered reduces the pollution produced by mining and non-mining activities to levels acceptable by law. On the contrary, it is observed that the absence of mining units has an influence on the increase in urban pollution produced by cities and towns near the watershed, which affects water quality. This research shows that formal mining activity in the watershed has a positive impact on water quality and allows future research to be opened regarding the influence on other environmental factors such as air, soil, biodiversity and even the social environment. Finally, this research is the beginning of a change in perspective on mining in the country.