The study aimed to assess the performance of Yarmouk station for treating sewage water in Mosul City, Ninevah province. The station's performance was estimated based on the analysis of water quality data, including measurements of TSS, TDS, EC, pH, temperature, turbidity, TH, ALK, SO₄^2-, Mg²⁺, Ca²⁺, K⁺, Na⁺, HCO₃^-, Cl^-, and NO^3-. Additionally, the biological oxygen demand (BOD) and chemical oxygen demand (COD) of the station were measured. The study results showed that the station's water matched the standard specifications for water quality, and the treated water met the WQI water quality standards. The efficiency of treatment stations is generally measured by their ability to remove organic matter, which can be elucidated through the amount of BOD and TSS removed. The station's efficiency in removing BOD was found to be 82.8%, and the removal efficiency for TSS was 85.2%. The results also indicated that the water discharged from the station is suitable for irrigation according to KR and SAR values and within irrigation guidelines. Overall, the station was found to operate efficiently within the Iraqi discharge standards.