Abstract: An apparatus for directing and controlling the flow of water between the supply and return of a solar collecting device, the cold water inlet and hot water outlet of a water heater and the cold water source and hot water feed of conventional household plumbing. The Water Flow Controller Device includes a cold water source connector, a hot water feed connector, a collector supply connector, a collector return connector, a cold water inlet connector, and a hot water outlet connector. The hot water outlet connector is bifurcated to provide independent water flows paths for the hot water and the collector return water. The Water Flow Controller Device circulates water through a connected solar collecting device when the temperature at the output of the solar collecting device is above the temperature of the water at the bottom of a connected water heater.