Desalinating brackish surface water in southern Iraq using reverse osmosis technology is crucial due to water scarcity. Actual water samples from three locations were used in a pilot RO membrane system. The study aimed to analyze the system's performance and water quality changes over time. Results showed 95.9% to 98% removal of total dissolved solids and significant reductions in turbidity and total organic carbon in the feed water. The system achieved a wide range of water flux rates, indicating effective desalination of the brackish water.