Solar Desalination The chemical process of changing seawater into potable or fresh water is called desalination As populations increase and sources of high quality, fresh drinking water decrease, using desalination processes to provide freshwater when other sources and treatment procedures are uneconomical or not environmentally responsible is becoming more and more common. Desalination is any process that removes excess salts and other minerals from water. In most desalination processes, saltwater (also called "feed water") is treated and two streams of water are produced: Treated freshwater that has low concentrations of salts and minerals. Concentrate or brine, which has salt and mineral concentrations higher than that of the feed water.