Water is one of the most essential necessities and is employed for a variety of purposes. Surface water needs have increased as a result of dramatic climate change, ongoing population growth, and changing human lifestyles. In addition, the pollution of surface water has become a global environmental issue. Monitoring of surface water is essential to know the current status of water quality and maintain it at certain desirable level. Therefore, this study has highlighted an evaluation of surface water quality (WQ) for drinking purposes in the Mahanadi River Basin, Odisha, by implementing the integrated use of entropy-based WQI (E-WQI), with reliability based MCDMs (Multiple-criteria decision making) such as Fuzzy (F)-Analytic Hierarchy Process (AHP) have been employed for the reliability and practicability for river water quality monitoring and assessment. To perform this, water samples were collected from 16 different locations across the stretch and 20 parameters were analysed for a time frame of 2020–2023 respectively. From the physicochemical results, it is observed that the study area predominantly comprises of slightly alkaline in nature. Parameter TKN and coliform exhibits higher values and crosses the acceptable limits. As per entropy framework, E-WQI revealed that 12.5% (sites X-8 and 16) and 6.25% (site X-9) of samples belong to poor or very poor water quality. It indicated that, due to the influence of rock-water interactions, evaporation, and reverse ion exchange, the chemical composition of surface water varied. Even though it is a crucial component in determining how underutilized water stations are rated, WQI involves contradictory issues. Based on that, MCDM models, such as F-AHP were implemented to resolve conflicts, pertaining to the WQI index. The degree of fuzzy weights were in the order of TC > TKN > EC > TDS > Cl−.The value at all sampling sites varied between 53.7 and 296.65. Out of 16 water samples, 50% represents good water, 25% indicate medium water, 25% indicate poor/very poor and finally, 6.25% indicate water unsuitable for domestic purposes. Following this, the proposed approach depicted X-(9) was the most polluted in comparison with other locations, followed by X-(2), (8) and (16) respectively. This was evident from the highest E-WQI values at this location. It also accompanied with high values of TC, TKN, EC, SAR, TDS, TH, Cl−, SO42− and Fe2+, which were likewise the highest of all the areas and greater than their desired concentration. The major sources of contamination included discharge from households, uncovered septic tanks, leachate from waste dump sites, and excess utilization of fertilizers in the agricultural sector. The results of the two models mentioned above allow for the identification of the anthropogenic pressure that corresponds to the anthropogenic impact on WQ, the prioritization and monitoring of restoration measures, and the optimization of monitoring programs that are already in place to account for significant anthropogenic pressures. The study is vital for decision-makers as it promotes sustainable surface water use and ensures water security in the studied area.