At this time especially uncontaminated water is meagre and with speedy computerization and deforestation, it is not an everlasting contribution of nature. It is so important for daily life that it is impossible to live without it. Moreover, there is no substitute for it. Hence water resources should be used in the best possible economic way and research should be carried on for finding out dry methods of production. In this study, Water Quality Index (WQI) of Maldevta waterfall, Dehradun was analyzed with the help of ten physicochemical parameters such as Alkalinity, Calcium, Chloride, Electrical Conductivity, Magnesium, Nitrate, pH, Sulfate, Total Dissolved Solid, Total Hardness to know the suitability for drinking purpose during pre and post monsoon seasons of the year 2021..The values of Calcium, Nitrate, Total Dissolved Solid which exceeded the permissible limit during both monsoon seasons. The calculated Water Quality Index value are 100.091 during pre-monsoon season and 91.937 during post-monsoon season. This water quality rating study clearly shows that, the status of the water body is not suitable for drinking. This research offered the need of an effective Assessment of the waterfalls quality and its utility for human health.