The open dumpsite is frequently chosen as the trash disposal option in most emerging economies, yet it poses serious environmental risks. Mahanadi River Basin (MRB) is one of Odisha’s most heavily populated by agriculture and drinking, particularly for human consumption and farming. It faces severe surface water quality and quantity constraints. Water assessment indices such as Criteria Importance through Inter-criteria Correlation (CRITIC) and MCDM techniques like Complex Proportional Assessment (COPRAS) have been employed in the evaluation of water quality for human use, using integrated techniques. The study focuses on 20 water quality parameters taken from 19 stations over a period of 2021–2023 and compared them with the World Health Organizations (WHO). To investigate the spatial distribution maps of all approaches, the geo-spatial tools (IDW method) were considered. Coliform and TKN concentration mostly responsible for the high index scores in all locations. From the findings of CWQI, it has been determined that higher water quality is found to be 84.21% and a value of 15.79% belonging to poor/extremely poor category. MCDMs like COPRAS has been utilized for ranking evaluation, which shows that the highest rating provided for each period, that would cite the sampling location with the highest pollution. For instance, S-9 was found to as most polluted site because of elevated degree of certain parameters containing SO₄^2-, SAR, EC, Cl^-, TKN, TDS, TH and TC. Based on the results, it is evident that deterioration in water quality is mostly correlated with population growth, urbanization, industry, agricultural output, and the growth of ecotourism and hospitality in high areas close to the source areas. This study’s uniqueness showed how to use water quality index methods to gauge or comprehend the quality of river water, and it seemed to hold promise for the future of water quality management.