A gray water collection and distribution system includes a main drain line, one or more black water sources connected to the main drain line, one or more gray water sources connected to the main drain line and a collection valve located down stream from at least one of the one or more black water sources. The collection valve includes an inlet connected to the main drain line, and an outlet connectable which can be switched to either a black water drain line or a gray water drain line, depending upon which type of water flow is detected.