A hot loop water supply apparatus comprises a heating vessel (1), an electric heater (5) to heat the water in the heating vessel, a hot water outlet (6) from near the top of the vessel, a hot water return inlet (7) to return hot water to near the bottom of the heating vessel, a hot water loop (9) interconnecting the hot water outlet and the hot water return inlet and arranged to feed hot water to single lever mixer taps (8) provided around the loop and recirculate hot water from the hot water outlet to the hot water return inlet, a thermostat (11) in the heating vessel controlling the electric heater and set at a predetermined temperature to maintain the water in the heating vessel and the hot water loop at a pasteurisation temperature, which is preferably above the maximum viable temperature of legionella bacteria.