Chlorinated compounds on reaction with natural organic substances present in water leads to the formation of trihalomethanes (THMs), a major type of disinfection by-products (DBPs). Trihalomethanes (THMs) are the most widely investigated DBPs in drinking water systems because of their carcinogenic potential and subsequent adverse effects on human health. This study investigated the effect of gastro-intestinal absorption factor on human health risk assessment. Monitoring and analysis of water quality parameters and THMs levels in drinking water treatment plants revealed that the average values (306.5 μg/L) exceeded the recommended US EPA guidelines of 80 μg/L. Spearman rank (rho) correlation coefficient indicated that dissolved organic carbon is the major parameter influencing THMs formation. Monte Carlo simulations base risk assessment study was conducted for three different exposure pathways. The observed human health risk exposure effects due to THMs were below the recommended USEPA level (1.0 × 10⁻⁶) for both the drinking water treatment plants. Seasonal disparity on risk estimation analysis revealed higher risk in summer season followed by autumn which is principally due to high concentration of THMs in summers.