Hydrochemical investigations of groundwater in an urban area of Lome, Togolese Republic were used to evaluate the groundwater quality. The quantities of chemical components (major and some minor elements, temperature, pH, TDS and EC) in groundwater samples were determined and submitted to statistical analysis. The majority of the samples contained high concentrations of Na+ and Cl- (Na-Cl water type). The samples also contained high concentrations of NO3-, which is a serious water quality issue. This NO3- originates from the soil surface and enters the groundwater by infiltration. NO3- and Cl- were the relegate parameter for the drinking use and their content in 78.94% and 63.15% of water samples were greater than 57 mg/L and 260 mg/L respectively. Na+ levels ranging from 37 mg/L to 1430 mg/L. Factor analysis and hierarchical cluster analysis were used to identify the key parameters that describe groundwater quality and cluster the wells into homogeneous zones for future monitoring of groundwater quality, respectively. All water samples analyzed have an EC ranging from 840 μS/cm to 8680 μS/cm which shows saline water. Only P4 was slightly mineralized and have lower EC (334 μS/cm). pH (5.07–7.42) was found to be function of HCO3- concentrations (73.2 mg/L to 463.6 mg/L) in the water.