Drinking water treatment reduces or eliminates certain health risks and ensures appropriate water quality by removing physical, chemical, and biological pollutants. The treatment process's increased need for energy, chemicals, and technological inputs raises the expense of producing water as well as its secondary environmental effects. The goal of this research is to use the Water Quality Index (WQI) and Life Cycle Assessment (LCA) to determine and assess the environmental effects of the Al-Hashimiyah Water Treatment Plant (WTP) in Babylon City, Iraq. The water quality index was employed as a criterion for categorizing and treating water in accordance with fundamental water characterization variables using a weighted arithmetic index technique. The LCA was supported by the Eco-Indicator 99 database and SimaPro 7.0 software. What makes this study unusual is the identification of two extra functional units related to decontamination, beyond the usual one cubic meter treated water. Samples of treated and raw water were gathered during a 25-month period, from March 2022 to March 2023, and were regularly tested. The results demonstrated that all chemical and physical characteristics (for both raw and processed water) met Iraqi criteria, with the exception of total suspended particles and electrical conductivity. According to LCA studies, certain environmental consequences grow as pollutant concentrations drop. Due to this, a more thorough analysis of the environmental performance of water treatment facilities is now required.