This study investigated the water quality in the northern section of the Shatt al-Arab River in southern Iraq using the Canadian water quality index (CCME-WQI) at three monitoring stations: Qurna, Al-Deir, and Al-Hartha. The study was conducted from December 2022 to November 2023. Monthly water samples were collected and analyzed for various environmental parameters, including water temperature, salinity, pH, total dissolved solids, light penetration, water velocity, reactive nitrate, ammonium ions, total phosphate, chlorophyll A, biological oxygen demand, and total suspended solids. The calculated water quality indices for the three stations were 57.8, 60.6, and 55.2, respectively, categorizing the water quality as "marginal," indicating susceptibility to pollution and deviation from ideal conditions.