Anion and cation concentration data analyzed in drinking water can be very useful in source identification with multivariate statistical methods. In this study, anions and cations were analyzed in samples collected from four regions by ion chromatography (IC). The effects of seasons and regions on ion concentrations were analyzed by variance analysis (ANOVA). Multivariate statistical methods such as principal component analysis (PCA), discriminant analysis (DA), and hierarchical cluster analysis (HCA) were used in the study. In the DA, the percentage of classification of the samples to the original regions was found to be 91.7%. HCA results revealed that Na+, Mg2+, and Ca2+ ions exhibited very similar behavior. In the PCA analysis, PC1 and PC2 explained 68.3% of the total variance for anions, 95.3% for cations, and 99.7% for Ca2+, Mg2+, and Na+. It has been observed that different water supply sources can be distinguished using Ca2', Mg2', and Na' cations, and it is also possible to differentiate regions belonging to the same source. Differences in ion concentrations may be caused by the chemicals used during treatment, the geological structure of the region, and seasonal effects. However, this study has demonstrated that chemometric techniques combined with IC can identify the source of drinking water samples when their regional origin is unknown.