A method of sanitising a section of a water purification apparatus able to provide a purified water stream having a conductivity of less than 1 µS/cm at 25°C to a dispense outlet, the water purification apparatus having a purified water recirculating section 32 including at least one deioniser 24 and a dispense outlet 46. The method comprises the steps of: providing recirculation in the purified water recirculating section 32； providing ozone-generation in the purified water recirculating section 32 after the at least one deioniser 24； allowing the ozone to circulate around the purified water recirculating section 32 to sanitise at least the part of the purified water recirculating section having the dispense outlet 46； and using ultra violet (UV) radiation to stop the sanitising prior to the at least one deioniser 24. Also claimed is the water purification apparatus per se 39 comprising: a purified water recirculating section 32 including at least one deioniser 24 and a dispense outlet 46； an ozone-generating unit 36； and an ultraviolet radiation unit 20. The deioniser 24 may be one or more of ion exchange resins, an electro-deionisation unit, a capacitive deionisation unit and a membrane capacitive deionisation unit.
