Quality of drinking water has become more important in India as a result of the numerous human activities that are contaminating it and the need to assure its continued safe use. Determining the quality of the treated water is crucial for this. In this study, the Mahanadi River in Odisha was taken into account, which has drawn significant attention due to rising urban pollution loads that have adversely damaged its ecosystem processes and water quality. 20 physicochemical parameters from 19 surface water samples collected during an 18-year period (2000–2018) were reviewed. Huge and diverse surface water quality databases were analyzed using multivariate statistical techniques such as correlation analysis, principal component analysis (PCA) and cluster analysis (CA). Using Karl Pearson’s correlation matrix, correlation analysis reveals a strong positive correlation of TDS, EC strongly correlated with B, Cl-, TH, and SO42- correlate with B and TH, Cl- with SO42- and Cl-, SO42- with TH. 19 sampling sites are grouped into three main clusters by CA using dendrogram plots to identify surface water characteristics. Following the use of PCA/FA, five primary components with a combined variance of 93.899 percent were identified as the root causes of the decline in water quality. TSS, EC, TDS, B, TH, Cl- and SO42- have all been correlated with (loading greater than 0.9) in the PC1, which accounted for 43.133 % of the total variance. COD, NH3-N, Free NH3, SAR; pH, F were all linked to the PC2, which accounted for 23.055 % of total variation, whereas the 3rd, 4th, and 5th PCs, while accounting for 12.866 %, 8.603 %, and 6.241 % of total variation, respectively. It confirms high pollution load in water samples. It is advised to regularly monitor the parameters in order to protect surface water supplies to maintain water quality for drinking.