In this study, we combined radon in water activity (222Rn), stable isotopes of inorganic carbon (δ13CDIC), water stable isotopes (δ18O; δ2H) as well as major and trace ions measured in 161 private wells to develop a conceptual hydrogeochemical model of the groundwater flow in this region. More specifically, the applied method consists of (1) analyses of the hydrogeochemical facies and their spatial distribution, (2) sequential multivariate analyses of the groundwater geochemistry and assessment of the evolutionary processes, (3) origin and distribution of 222Rn in the study area and (4) a conceptual model of the groundwater flowpath and mixing processes combining geochemistry and isotopes.