Abstract: A method of determining an operating water temperature for a boiling water heater includes the following steps: (a) adding water to a tank to a predetermined level; (b) heating the water in the tank to approximately 95 degrees Celsius; (c) applying sufficient heat to the water in the tanks so as to cause boiling of the water in the tank within a predetermined first period of time; (d) measuring the boiling water temperature of the water in the tank; and (e) subtracting a predetermined temperature from the boiling water temperature measured in step (d) to arrive at the operating water temperature.