Abstract: An automatic system for treating water, which consists of two treatment tanks adapted to be operated alternately. The tanks are interconnected with each other by a unique isolation valving system that permits one tank to be in use while the other is on standby. They are also connected to a single brine tank and alternate by being controlled with a novel, photo/electric water sensor, which reacts to a predetermined flow of water through the tanks. This system is very environmentally friendly by reducing the amount of water and salt used in the regeneration of the minerals compared with other systems operating today.