Hazaribagh is a major source of pollution and a center for the leather industry in Bangladesh. It is home to 1.2 million people and has 185 shoe factories. People who live in Hazaribagh consume surface water and groundwater for drinking and household activities. Implementation of a new law and government pressure has forced several tanneries to shift to areas allocated to industrial parks, but many others have remained. Our research set out to determine the impact of the tanning process on the surface water and groundwater of this area. In this study, surface and groundwater samples (a total of 42) from 6 different points around the tannery complex were analyzed during December 2019 and August 2020 in dry and rainy seasons, respectively. Our main purpose of this study was to find out the quality of the surface and groundwater in the sampling area, as well evaluate the seasonal change of different parameters. During the sampling, we set a route from the tannery source points to the Buriganga River, which is where the tannery effluents end up. The water’s chemical and physicochemical parameters were measured in accordance with the accepted protocol. Our main concern was the presence and concentration of heavy metals which were found to be significantly higher in the first three sampling locations. We also found that heavy metal concentrations dropped dramatically from the river’s upstream source to its final destination, the river Buriganga. Increasing distance from the source site and wastewater percolation to groundwater via soil may have caused this geographical variation in metal concentration. Although, rainwater may have diluted heavy metal concentrations, their levels were still above the permissible level. Heavy metals and other physicochemical parameters, like pH, DO, BOD, TDS, TSS, EC, Cl^``, and Na, were found in all surface and groundwater samples above national (DoE) and international (WHO) standards.