A method and apparatus for cleaning a waste collection pit of an animal housing facility. A storage tank or reservoir for water to be used in the cleaning operation is suspended inside the upper confines of the housing facility above the living quarters of the animals. Water from the storage tank is directed through a vertical down tube to a water distributor associated with each waste collection pit. Interposed in the vertical down tube for controlling the flow of water is a slide gate valve of a design to travel from a fully closed to fully open position within a short time interval. The storage tank provides a pressure head of water for the efficient flushing of wastes from the collection pit during a flushing operation. Water used in a flushing operation is collected either in a storage lagoon for recycling or for transport to a remote treatment or application location.