N.C. Gen. Stat. § 66-27.4: Local regulation of hot water heater safety features.

Nothing in this Article shall be interpreted as relieving any individual, firm, corporation or business from complying with additional protective regulations relating to the safety features of hot water heaters as may be prescribed by local law, county or municipal charter or ordinance; provided, however, that no local law, county or municipal charter or ordinance shall fix or govern the temperature or pressure settings of a pressure-temperature relief valve on an automatic hot water tank or heater covered by this Article if there is installed on such tank or heater a pressure-temperature relief valve having settings in compliance with the North Carolina Building Code. (1965, c. 860, s. 4.)