The Sequencing Batch Reactor system (SBR) is a major component of the municipal wastewater biological treatment system and water reclamation that provides high-quality water that could be reused in restricted plants that which require large quantities of water despite the lack of water. The research aims to investigate the performance of a pilot plant SBR unit under real operation conditions that was installed and operated in Al-Rustamiya Wastewater Treatment Plant (WWTP), Baghdad, Iraq. Results showed that the BOD5/COD ratio of the raw wastewater was within the average value at 0.66 emphasizing the organic nature of the influent flow and hence the amenability to biological treatment. The results also ensured that the treatment process improvement occurred by increasing the detention time for settling of up to 4.5 hr under real operating conditions. The removal of BOD5 and COD resulting from the treatment process of the SBR system reached 86% and 84% respectively, and the final effluent characteristics of SBR for 4 hr after settling time 3 and 4 hrs were within reuse within permissible limits for Iraqi quality standards for irrigation reuse (IQS-2012).