Fifty years ago, research and development funding through the U. S. Department of the Interior, Office of Saline Water was used to develop many of the water treatment technologies used today. These include reverse osmosis, electrodialysis, capacitive deionization, and some advanced thermal methods. Since that time, incremental advances to these methods have been made – for example, reverse osmosis is now significantly more energy efficient than it was decades ago; electrodialysis membranes are available that are monovalent ion selective; and multiple effect distillation can now be carried out without the severe corrosion and scaling problems that hindered the metals first used in its application. But there has not been a significant change in the nature of the technologies used for desalination and treatment of impaired waters. In a sense, several decades of advances in materials science, both in understanding separations science, and in the development of new materials, have not been applied to the area of water treatment.