Water supply seems a mundane subject, yet as water supplies become stretched around the world, thinking of water as a chemical commodity may become an important paradigm. Historically, people settled near adequate water supplies or created major civil engineering projects to move water long distances to needy populations. This has helped to maintain public health, high standards of living, and a high quality of life. Today, chemical engineers are working on separation processes to purify impaired waters such as brackish surface and groundwater, seawater, and recycled water. For major population centers, these treatment processes must be done on a very large-scale, to very high standards, and at a very low cost by using chemical engineering concepts. The U.S. government's Bureau of Reclamation has supported research and applied solutions to increase water supplies for municipal, industrial, and agricultural purposes. This presentation describes some of these projects.