This study aimed to evaluate the efficiency and quality of water in the unified Al-Aziziyah–Al-Hafariya water treatment project in Wasit Governorate. Bacteriological parameters, including Total coliform, Fecal coliform, and Escherichia coli, as well as selected heavy metals (Cadmium, Zinc, and Chromium), were analyzed at different stages of water treatment. The results showed that river water exhibited the highest levels of bacterial contamination, with Total coliform, Fecal coliform, and E. coli reaching 1100, 463, and 1.6 MPN (Most Probable Number)/100 mL, respectively. A progressive reduction in bacterial counts was observed through sedimentation and treatment stages, with complete removal of E. coli in both final treated water and distribution network samples. Similarly, heavy metal concentrations were highest in river water and gradually decreased during treatment. Chromium showed the most noticeable reduction, while Cadmium and Zinc remained within low concentration ranges throughout the treatment process. The findings indicate that the water treatment plant is effective in significantly reducing both microbial and chemical contaminants, producing water that meets acceptable safety levels for distribution. However, continuous monitoring is recommended to ensure sustained water quality.