High arsenic (As) contents in groundwater were found in the Bafgh area in central Iran and chosen for hydrogeochemical study. A total of 20 groundwater samples were collected from existing tube wells in the study areas in 2013 and analyzed. The water chemistry is predominantly of Na–Cl type, with concentrations of dissolved As in the range between 0.9 and 74.7 μg/L. The chondrite-normalized rare earth elements patterns exhibited a flat profile, positive Gd anomaly with a predominance of light rare earth elements (LREEs) over heavy rare earth elements (HREEs), suggest that they originated from the same source. The metals in the groundwater of the region have a geological origin.