Kanpur city generates approximately 1500 metric tons of municipal solid waste per day. The dumpsite lacks lining, and no impermeable barrier system controls groundwater contamination from leachate percolation. Groundwater samples were collected in three different seasons (June 2020 to July 21) to assess the impact of existing dumpsite on groundwater quality. Various indices including the water quality index (WQI), heavy metal pollution index (HPI), contamination index, and heavy metal evaluation index (HEI) were assessed. These indices aimed to assess groundwater suitability for drinking purposes. Additionally, parameters such as sodium absorption ratio (SAR), sodium percentage (%Na), magnesium hazard ratio, and soluble sodium percentage (SSP) of groundwater were analyzed to assess its suitability for irrigation. The results of groundwater quality parameters indicated elevated concentrations of heavy metals (iron, chromium, nickel, and zinc) and other factors, including electrical conductivity, sodium, potassium, etc. during the monsoon season. The values of drinking water indices (WQI = 65.36, HPI = 258.98, HEI = 8.02) and most of the irrigation water quality indices (SAR = 24.07, %Na = 76.38, SSP = 75.34, KR = 3.05) were highest in monsoon season. Calculated values of various indices revealed that groundwater suitability for both drinking and irrigation is lowest during the monsoon season, followed by pre-monsoon and post-monsoon periods.