In the early 1970s, Mekorot was among the first to investigate and actually implement the RO process as an alternative to the much higher energy-intensive and more expensive thermal processes. Mekorot, assisted by Israeli universities and in cooperation with leading membrane manufacturers and other equipment suppliers, made extensive research efforts to stretch, as far as possible, existing and developing RO technologies to improve performance regarding reliability and cost. This was accomplished by comprehensive pilot testing of all major RO membranes and appropriate antiscalants. More recently, new developments such as integrated membrane systems (IMS) have been investigated in the framework of international research projects supported by the EU and MEDRC. In this paper the economic impact of R&D and ongoing research activities are discussed.