The study area Faridabad District is situated in the south-eastern part of state Haryana in the National Capital Region Delhi, India. From past few decades, change in land use pattern has affected water resources in the area both in terms of quantity and quality. To avoid further degradation of groundwater, the present study aims to identify the sources and the processes contributing to groundwater salinity and pollution, based on hydrogeochemistry in integration with GIS. The groundwater vulnerability has been assessed by rock–water interaction, geochemical processes, river/canal seepage, pollution and intermixing, variation in land use activities. The study suggests that the region-specific factors such as unplanned land use pattern and waste disposal, drainage as well as intermixing of groundwater play significant role in groundwater pollution besides geochemical processes. Salinity in shallow aquifers is usually as a consequence of leaching of evaporates in waterlogged areas along canals during rain or irrigation; mineral weathering; evaporation induced concentration of dissolved salts; saline groundwater movement from deeper to shallower aquifers due to continued indiscriminate groundwater over-abstraction; and expanding lateral extent of pollution in the overexploited aquifers.