A housing (20) for an oral irrigator having a hand piece (26) includes a base unit (22) having an upper, a lower portion (32, 30), the lower portion engaged with a support surface having an upper surface defining a recess (38) for receiving the hand piece, and the lower portion defining a peripheral shoulder (56). The upper portion extends upwardly from the lower portion, defines a top surface (62), the top surface defining a port and a key structure (66)； the upper portion being positioned inside the peripheral shoulder. A receiver (24) is positionable on the base unit in a first configuration and in a second configuration.
