The following table of water heater codes is for reference & sales purposes only it is by no means a comprehensive interpretation of the plumbing code but merely a condensation of the typical issues that result in additional charges.



Water Heater Code Short Desc Technical Answer Explanation
502.1 General Water heaters shall be installed in accordance with the manufacturer’s installation instructions. Oil-fired water heaters shall conform to the requirements of this code and the International Mechanical Code. Electric water heaters shall conform to the requirements of this code and provisions of the ICC Electrical Code listed in Chapter 13. Gas-fired water heaters shall conform to the requirements of the International Fuel Gas Code. Manufacturer’s specifications over rule the code.
P2903.9.2 Water Heater Valve A readily accessible full-open valve shall be installed in the cold-water supply pipe to each water heater at or near the water heater. The water heater needs to have its own shut off valve separate from the main shut off for the house.
P2903.4 Thermal expansion In addition to the required pressure relief valve, an approved device for thermal expansion control shall be installed on any water system utilizing storage water heating equipment whenever the building supply pressure is greater than the required relief valve pressure setting or when any device, such as a pressure reducing valve, backflow preventer or check valve is installed that prevents pressure relief through the building supply. The thermal expansion control device shall be sized in accordance with the manufacturer’s installation instructions. A properly sized thermal expansion tank is necessary with all tank style water heaters in locations where a pressure reducing valve or check valve is installed (Almost all city water & most well systems).
504.7 Required pan When water heaters or hot water storage tanks are installed in remote locations such as suspended ceiling spaces or in attics the tank or heater shall rest in a galvanized steel or other metal pan of equal corrosive resistance having a thickness at least equal to 0.0276 inch (0.7 MM) galvanized sheet steel. Exception: Electric water healers may rest in a high impact plastic pan of at least 1/16 inch (1.6 mm) thickness
504.7.1 Pan size and drain The pan shall be not less, than 1.5 inches (38 mm) deep and shall be of sufficient size and shape to receive all dripping or condensate from the tank or water heater. The pan shall be drained by an indirect waste pipe having a minimum diameter of 1 inch (19 mm). Explanation
504.7.2 Pan drain termination The pan drain shall extend full-size and terminate over a suitably located indirect waste receptor or floor drain or extend to the exterior of the building and terminate not less than 6 inches (152 mm) and not more than 24 inches (610 mm) above the adjacent ground surface. A broader interpretation is that a water heater installed at or above a living space needs a drip pan (504.7). The pan needs to be at least 1 1/2” deep, large enough to contain a leak, and have a 1” drain pipe leading out (504.7.1). The drain pipe needs to run outside the house or into a floor drain and has to stop at least 6” but not more than 24” from the ground (504.7.2)
Water Heater Code Short Desc Technical Answer Explanation



422.31 Disconnection of Permanently Connected Appliances (B) Appliances Rated Over 300 Volt-Amperes or 1/8 Horsepower.For permanently connected appliances rated at over 300 volt-amperes or 1/8 hp, the branch-circuit switch or circuit breaker shall be permitted to serve as the disconnecting means where the switch or circuit breaker is within sight from the appliance or is capable of being locked in the open position. For all practical purposes one volt-amp= one watt.
The electrical board in Raleigh takes a more “severe” interpretation of this code and does not consider breaker lockouts at the panel box to be sufficient. Therefore, If the breaker box is not within sight of the water heater or dishwasher a disconnect switch within sight of the unit is mandatory. FYI, Part “A” of the code states that appliances under 1/8 hp or under 300 VA can use the breaker as the sole disconnect means.
VI Equipment Grounding and Equipment Grounding Conductors Equipment Grounding and Equipment Grounding Conductors In short, all residential electric water heaters need to be grounded properly. It is no longer acceptable to ground the unit through the plumbing as some older units were.
250.110 Equipment Fastened in Place or Connected by
Permanent Wiring Methods (Fixed)
Exposed non-current-carrying metal parts of fixed equipment likely to become energized shall be grounded under any of the following conditions:(1) Where within 2.5 m (8 ft) vertically or 1.5 m (5 ft) horizontally of ground or grounded metal objects and subject to contact by persons(2) Where located in a wet or damp location and not isolated(3) Where in electrical contact with metal .


G2408.2 (305.2) Elevation of ignition source Equipment and appliances having an ignition source shall be elevated such that the source of ignition is not less than 18 inches (457 mm) above the floor in hazardous locations and private garages. For the purpose of this section, rooms or spaces that are not part of the living space of a dwelling unit and that communicate directly with a private garage through openings shall be considered to be part of the private garage. Water heaters located in garages or storage rooms where there are combustible materials stored need to be on a stand a minimum of 18” high.
G2418.2 (408.2) Drips Where wet gas exists, a drip shall be provided at any point in the line of pipe where condensate could collect. A drip shall also be provided at the outlet of the meter and shall be installed so as to constitute a trap wherein an accumulation of condensate will shut off the flow of gas before the condensate will run back into the meter. Explanation
G2418.4 (408.4) Sediment trap Where a sediment trap is not incorporated as a part of the gas utilization equipment, a sediment trap shall be installed as close to the inlet of the equipment as practical. The sediment trap shall be either a tee fitting with a capped nipple in the bottom opening of the run of the tee or other device approved as an effective sediment trap. Illuminating appliances, ranges, clothes dryers, and outdoor grills need not be so equipped. A drip leg or sediment trap (similar construction) needs to be located as close to the appliance it serves as possible.
G2419.5 (409.5) Equipment shutoff valve Each appliance shall be provided with a shutoff valve separate from the appliance. The shutoff valve shall be located in the same room as the appliance, not further than 6 feet (1829 mm) from the appliance, and shall be installed upstream from the union, connector or quick disconnect device it serves. Such shutoff valves shall be provided with ready access. There needs to be a gas shut off valve that serves the water heater exclusively within 6’ of the unit