The development and production of fresh potable water by reverse osmosis (RO) from the high saline Arabian Gulf sea requires several considerations. Among the number of considerations are minimized energy consumption, improved membrane performance, increased recovery and salt rejection, and improved materials of construction. The state-of-the-art for selection of appropriate corrosion-resistant alloys for a specific environment is not sufficiently advanced to make the obvious choices for a specific environment. Many metallic components in RO units still exhibit corrosion attacks in different forms. Localized corrosion in the form of pitting and crevice and mechanically induced erosion-corrosion are some of the problems behind many of the failures in RO equipment. It still remains necessary to conduct laboratory and plant testing of candidate alloys to establish those alloys that may be suitable for use. Results of laboratory tests conducted on a number of candidate construction materials for the various components and piping systems are described. The materials were exposed to an erosion-corrosion regime.