Water Saver utilizes capacitive deionization technology to reduce dissolved ion concentration, thus lowering the makeup water conductivity prior to use in an evaporative cooling system. Makeup water entering the capacitive deionization pretreatment system passes through individual cylinders that contain oppositely charged supercapacitors. Dissolved ions (except silica) are removed from the water as they are absorbed onto the charged capacitors. A typical 50 percent ion reduction allows the operating cycles of concentration to be safely doubled without an increase in scale or corrosion potential. Benefits include improved water efficiency by increasing operating cycles of concentration and reduced blowdown and treatment chemicals sent to drain.