In this investigation, an innovative index was developed based on the fuzzy inference system for assessing the quality of bottled drinking waters. A method was developed to aggregate the values obtained from the defuzzification step. A total number of 24 quality parameters revealing the characteristics of bottled were in terms of physiochemical, dietary, toxic, and pathogenic aspects were selected as the input parameters. 30 samples were taken from the independent brands found in the Hamadan province retail market to evaluate the bottled water quality index (BWQI). Results show that the values obtained from measuring the parameters are in the range of the standard levels set by national regulations. The BWQI scores obtained from samples were in the range of 61.2-73.8 attributing to the marginal and fair descriptive classes. The drinking bottled water samples had better scores because of low contents of NO 3 , NO 2 , Fe, Mn, Cu, and Zn that are subjugated public distribution systems having the severe standards on urban water treatment plants for in case safe water. The mineral bottled water samples examination indicated that they are generally affected by the mineral contents of sedimentary rocks and NO 3 leaks from fertilizers used in the agricultural doings and also they do not elaborate the rigorous scrutiny system alike those donned in the public water distribution systems. Sensitivity analysis using the Monte Carlo algorithm reveals that the parameters NO 3 , Na, hardness, and NO 2 have the most impact on the BWQI scores.