A development program of a small-scale desalination unit, formerly designed and manufactured, was adopted to reduce the production cost of water and minimize the deviation in the water characteristics. Process design and full engineering were performed; the system was manufactured locally. It was operated continuously for 1 year. Monitoring of feed and product water characteristics, quality and quantity and recording of plant performance were essential objectives to evaluate the prototype. Deviations of the water from design quantity and quality, repeated shut-downs due to blocking of fine filtration, and failure of the water intake were the main features of recorded failures, as well as the high water production cost, which was mainly attributed to over-designing in certain elements of the system. The working development program can be summarized as follows: membrane modules rearrangement, elimination of the second stage of desalting, insertion of a suck-back tank to protect the membranes, and elimination of the carbon filter.