Abstract Groundwater in the Pleistocene aquifer in the Cu Chi area was massively exploited for a long period to supply human needs. To evaluate the current groundwater quality and ongoing hydrogeochemical processes in Pleistocene aquifer, a total of 21 groundwater samples were analyzed. The concentrations of Ca2+, Mg2+, Na+, K+, Fetotal, NH4 +, NO3 −, PO4 3-, Cl−, HCO3 − and SO4 2- were determined for the investigations. The rank of major cations in the study area is Na+ > Ca2+ > Mg2+, and Ca2+ > Na+ > Mg2+ respectively. The rank of major anions in the study area is Cl− > HCO3 − > SO4 2- respectively. The bivariate plot explanations indicate many processes that impact the chemical composition of groundwater in the study area, including ion exchange, chemical weathering, and human activity. The saturation index (SI) of halite is oversaturated (SI > 0), while this figure for CaSO4 was negative (SI < 0) in all the samples. Quality groundwater for irrigation purposes showed that all groundwater samples were sensitive to low pH and alkalinity values, therefore, it is necessary to be treated before use for irrigation purposes.