The need for good-quality water in Cyprus continues to be the driving force for the use of reverse osmosis to desalinate brackish water and seawater for irrigation and potable use. Much work continues both to optimize the process designs for new plants and to refine the operation of existing ones. The pilot plant has been operated successfully for over 2 years. It uses four TFC (R) 2832SS-540 Magnum (R) elements in one tube operating at 50% recovery. It has been monitored using the NormPro (R) normalization software to assess the performance of the elements during this time. The normalized data are reviewed and an interpretation of the results given. The effect of the pretreatment on fouling is assessed and the results of the cleaning reviewed. The study shows the importance of monitoring in order to ensure satisfactory long-term stable system performance.