Periodic assessment of drinking water quality is essential for protecting public health and supporting sustainable water resource management. This study evaluated the chemical quality of drinking water from the Central-Far Western Terai region of Nepal using physicochemical characteristics, nutrients, major ions, selected trace elements, and an integrated Water Quality Index (WQI). Eleven drinking water samples were collected during May 2025 and analyzed for twenty-two water quality parameters. Descriptive statistics were complemented with 10,000 bootstrap resamples to estimate robust 95% confidence intervals for parameter means despite the limited sample size. Spearman’s rank correlation analysis was used to examine associations among the measured variables. Overall chemical water quality at each sampling site was evaluated using a weighted arithmetic WQI based on parameters with established drinking-water guideline values from the World Health Organization (WHO) and the Nepal Drinking Water Quality Standards (NDWQS). Most measured parameters complied with the applicable guideline values. Significant positive correlations were observed between electrical conductivity and total dissolved solids (ρ = 0.964), chloride and bromide (ρ = 0.856), sodium and magnesium (ρ = 0.864), and sodium and sodium adsorption ratio (ρ = 0.936). Strong correlations among dissolved nitrogen fractions were interpreted cautiously because some variables are mathematically related. WQI values ranged from 7.28 to 26.12 (mean = 14.02 ± 5.43), and all sampling sites were classified as Excellent (WQI < 50), indicating favorable chemical water quality based on the measured parameters included in the index. However, these findings should be interpreted as a baseline chemical assessment because microbiological quality, seasonal variability, and broader regional representativeness were beyond the scope of this study. The results provide useful baseline information for future groundwater monitoring and drinking water management in the Central-Far Western Terai region of Nepal.
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