The objectives of this study are to determine the most significant spatial variation of drinking water pollutant and to identify the most significant parameters in each group of physico- chemical parameters (PCPs), Inorganic parameters (IOPs), heavy metals and organic parameters (HMOPs) and pesticides parameters (PPs). The Discriminant Analysis (DA) and One- Way Analysis of variance (ANOVA) showed spatial variation on four station categories and the variance of four group parameter in water drinking quality while principle component analysis (PCA) was carried out to identify the most significant of each water quality parameters base on given group. DA and ANOVA successfully reduced the physico and inorganic pollutants concentration with significant value 98.63% and 96.90%. PCA revealed six most significant drinking water quality parameters for PCPs, nine significant parameters for IOPs, fourteen parameters on HMOPs and four significant of PPs with the p value less than 0.05 (p < 0.05). Therefore, this study proves that chemometric method is the alternative way to explain the characteristic of the drinking water quality and could reduce several parameters and sampling points in the future sampling strategy.

This study aims to identify the most significant parameters in drinking water quality, spatial disparities of treated water (TW) and performance of water treatment plant (WTP) in Selangor. Physico- chemical (PCPs), Inorganic (IPs), Heavy metal and organic (HMOPs) and pesticide (PPs) were selected as parameters to discriminate the source of WTP pollutant. Chemometric technique such as principle component analysis (PCA), one-way analysis of variance (ANOVA) and discriminant analysis (DA) was applied to validate the performance of water treatment plant. PCA identified the most significant parameters which are highlighted six out of eight parameters for PCPs, six out of twelve parameters for IPs, nine out of sixteen parameters for HMOPs and all seventh parameters for PP. ANOVA for distinguish two categories region in WTP and showed both of PCPs and IPs had significant differences due to their concentration (p < 0.5) and HMOPs suggested fifth of significant differences within regions (p < 0.05). PP doesn’t give any significant differences (p > 0.05). DA was suggested PCPs, IPs and HMOPs in good performance (76.96%, 91.90% and 93.27%) except PP (50.43%). We can conclude that this chemometric technique can expose which area of WTP need to be properly maintains their performance to produce high quality of drinking water.