The subject matter discloses a water dispenser, comprising a water container, a water supply system, a fluid pump and a control unit. The water supply system is configured to supply water from the water container to a hot water reservoir and to a cold water reservoir and is further configured to provide hot water from said hot water reservoir and cold water from said cold water reservoir to a user of said water dispenser. The fluid pump is fluidly coupled to a fluid flow system and the water supply system and is configured to pump a quantity of hot water from the hot water reservoir to the water container via a fluid flow conduit of the fluid flow system for a cleansing operation of at least the fluid flow system. The control unit is in communication with the fluid pump for controlling the cleansing operation.