Gas water heater controls monitor and control the pilot light and water temperature by regulating the flow of gas to the burner. These controls are compatible to specific gas types.

Electric water heater controls, or thermostats, regulate the flow of electricity to the heating elements by opening and closing the contacts. Electric heaters with a large tank capacity typically have two controls, called upper and lower thermostats, that sense the water temperature in both the top and bottom of the tank. Electric heating elements cycle on and off depending on hot water demand.