device for controlling the water level of a swimming pool or the like body of water; device for installation beneath the peripheral edge known as a coping-bond beam or decking surface thereof to provide a continuous discharge of excessive water from the pool separate from the pool recirculating system; device comprises a tubular conduit having its inlet opening formed as a substantially-rectangular elongated mouth the mouth is formed as an integral part of the throat portion which extends rearward to form an outlet defined as a circumferential, extended duct having a diameter generally from about two to six inches, whereby various well-known piping components can be securely attached