Devices and methods for sterilizing bottled water coolers and water dispensed therefrom. According to certain embodiments, the invention includes a bottled water cooler, which comprises a water bottle, an exterior cabinet, a cold tank, a bottle receptacle located on top of the cold tank that is configured to receive the water bottle in an inverted position, and an ozone generator. The ozone generator is capable of dispensing ozone gas within the space located above a volume of water contained within the cold tank, such that the ozone gas will be effective to sterilize the interior portions of the cold tank located above the volume of water.
