Groundwater quality evaluation for irrigation and drinking purposes is of utmost importance in semi-arid and arid regions of the globe and is a great tool for sustainable development. This study focuses on Dalgan basin in southeast Iran with the objectives of monitoring and assessment of physicochemical parameters (pH, EC, TDS, and T), cations (K+, Na+, Ca2+, and Mg2+), major anions (Cl−, HCO3−, and SO42−), and calculation of groundwater quality indexes (WQI, and EWQI) for irrigation and drinking purposes. In this research, we also prioritize the wells based on the groundwater quality index using the analytic hierarchy process and data envelopment analysis (AHP- DEA) model. Use of multivariate statistical techniques including correlation analysis (CA) and principal component analysis (PCA) indicated that geogenic (i.e. interaction of water-rock, climatic conditions, high evaporation) and anthropogenic (i.e. agricultural fertilizer) sources are responsible for variation in physicochemical parameters in groundwater of the study area. The results of the study showed that the simultaneous use of these methods and indicators is very effective and suitable in determining groundwater quality and prioritizing wells of any region.