Since the early days of commissioning in 1990, the Addur SWRO desalination plant has been going through a series of predicaments. The most crucial was the inability of the RO System to attain the plant＇s design production of 10 mIgd. This is perceived as a direct reflection of the abnormal feed water condition. Mainly due to seasonal changes and high feed water SDI exiting the pre-treatment System. In November 1995, the Addur plant went through a new phase change when the opportunity had risen for three RO trains to be replaced with new membranes, while pre-treatment problems remain unresolved. In its entirety, this was viewed as a rewarding experience in the sense that it provided a new keystone to examine the pre-treatment system performance and its impact over the production of new membranes, which is the essence of this paper. In addition to the one-year operating performance assessment of the new membranes, the paper will also discuss the production prediction of these membranes under the prevailing pre-treatment conditions. The recent modifications, which inspired the major step change of installing new membranes, will be discussed. In addition, and more importantly, it is to provide clear illustration of the upcoming plant rehabilitation which is to move forward the Addur SWRO desalination plant towards a full plant production.