The Uniform Plumbing Code (UPC) governs the construction, location and installation of fuel-burning and other types of water heaters.
The UPC defines a water heater, or water heating boiler, as an appliance designed primarily to supply hot water for domestic or commercial purposes, and equipped with automatic controls limiting water temperature to a maximum of 210° F. The water heater thermostat is a device used to set the water temperature within the holding tank, and the UPC does not recommend or mandate a temperature setting for the thermostat, thus making it a “silent temperature” setting. The UPC does, however, contain regulations for minimum requirements that focus on the health, safety and welfare of the public by mandating specific requirements for the water heater and plumbing fixtures.