The National Capital Region (NCR) of Delhi is one of the most extensively populated regions in the world. A major part of it lies in the flood plains of Upper Yamuna basin which is traditionally confined upto the confluence of Yamuna River with Hindon River. These areas have undergone rapid urbanization in recent years. The study area, confined to the flood plains of Yamuna River in parts of Delhi, New Okhla Industrial Development Area (Noida) and Faridabad of NCR, shows a trend of changes in hydrochemical character of the groundwater system that are related to the land use and land cover pattern. The article attempts to understand the relation between the surface and groundwater quality with the land use pattern and how emergence of urban clusters has influenced the evolution of hydrochemical facies in parts of the NCR. It also tries to link sources of salinity in groundwater with these changes using stable isotopic data.