Municipal Code of Chicago § 18-29-501.1 Scope.
18-29-501.1 Scope.
The provisions of this article shall govern the materials, design and installation of water heaters and the related safety devices and appurtenances.
Water Heaters (18-29-501 et seq.)
Municipal Code of Chicago tit. 18, ch. 18-29, art. 5
in effectMunicipal Code of Chicago § 18-29-501.2 Standards.
18-29-501.2 Standards.
Domestic electric water heaters shall be listed in accordance with UL 174 or UL 1453 and be installed in accordance with the Chicago Electrical Code. Commercial electric water heaters shall be listed in accordance with UL 1453 and be installed in accordance with the Chicago Electrical Code. Fuel gas-fired water heaters shall be listed in accordance with ANSI Z21.10.1/CSA 4.1 or ANSI Z21.10.3/CSA 4.3 and be installed in accordance with the Chicago Fuel Gas Code. Oil-fired water heaters shall be listed in accordance with UL 732 and be installed in accordance with the Chicago Mechanical Code. Solid-fuel-fired water heaters shall be listed in accordance with UL 2523 and be installed in accordance with the Chicago Mechanical Code. Solar thermal water heating systems shall comply with Chapter 14 of the Chicago Mechanical Code and ICC 900/SRCC 300.
(Amend Coun. J. 6-17-26, p. 45214, Art. IV, § 38)
Municipal Code of Chicago § 18-29-501.3 Drain valves.
18-29-501.3 Drain valves.
Each heated water storage tank shall be provided with a sludge drain pipe which shall be connected at the lowest level of the bottom section of the tank. This drain shall be provided with a control valve with a clear waterway equal to the area of the sludge drain pipe, and shall discharge through an indirect connection into the drainage system of the building. Drain valves shall conform to ASSE 1005.
Municipal Code of Chicago § 18-29-501.4 Location.
18-29-501.4 Location.
Water heaters and storage tanks shall be located and connected so as to provide access for observation, maintenance, servicing and replacement. Water heaters shall be capable of being removed without first removing a permanent portion of the building structure.
(Amend Coun. J. 6-17-26, p. 45214, Art. IV, § 38)
Municipal Code of Chicago § 18-29-501.5 Water heater labeling.
18-29-501.5 Water heater labeling.
All water heaters shall be third-party certified. Listing by Underwriters Laboratories, CSA International or the National Board of Boiler and Pressure Vessel Inspectors shall constitute evidence of conformance with these standards.
(Amend Coun. J. 10-14-21, p. 37722, Art. V, § 1)
Municipal Code of Chicago § 18-29-501.6 Tankless water heaters.
18-29-501.6 Tankless water heaters.
The temperature of water from tankless water heaters shall be a maximum of 140°F (60°C) when intended for domestic uses. This provision shall not supersede the requirement for protective shower valves in accordance with Section 18-29-424.3.
(Amend Coun. J. 10-14-21, p. 37722, Art. V, § 2)
Municipal Code of Chicago § 18-29-501.6.1 Coils.
18-29-501.6.1 Coils.
Indirect, external, tankless or submerged coils used in heating water shall be equipped with a thermostatic mixing valve or valves when not connected to a storage tank. A pressure relief valve or expansion tank shall be installed on the cold water inlet to the heater. A temperature and pressure relief valve shall be installed on the tempered line with the temperature sensing element immersed in the tempered water pipe as close as possible to the mixing valve.
Municipal Code of Chicago § 18-29-501.7 Pressure marking of storage tanks.
18-29-501.7 Pressure marking of storage tanks.
Storage tanks and water heaters installed for domestic hot water shall have the maximum allowable working pressure clearly and indelibly stamped in the metal or marked on a plate welded thereto or otherwise permanently attached. Such markings shall be in an accessible position outside of the tank so as to make inspection or reinspection readily possible.
Municipal Code of Chicago § 18-29-501.7.1
18-29-501.7.1
Water heaters of 200,000 BTU input per hour or more and storage tanks of 120 gallons (454 L) capacity or more shall be constructed in accordance with ASME Boiler and Pressure Vessel Code, Section IV.
Municipal Code of Chicago § 18-29-501.8 Temperature controls.
18-29-501.8 Temperature controls.
All hot water supply systems shall be equipped with automatic temperature controls capable of adjustments from the lowest to the highest acceptable temperature settings for the intended temperature operating range. Multiple temperature hot water supply systems shall be provided with thermostatic mixing valves to control the desired temperatures.
Municipal Code of Chicago § 18-29-501.8.1 Instantaneous water heaters.
18-29-501.8.1 Instantaneous water heaters.
Direct fired instantaneous water heaters shall be equipped with a thermostatic mixing valve or valves. A pressure relief valve shall be installed on or adjacent to the heater. A temperature and pressure relief valve shall be installed on the tempered line with the temperature sensing element immersed in the tempered water pipe as close as possible to the mixing valve.
Municipal Code of Chicago § 18-29-501.9 Heat exchangers.
18-29-501.9 Heat exchangers.
Heat exchangers using a toxic transfer fluid or having conditioning chemicals in the system shall be separated from the potable water by double wall construction. There shall be an air gap open to the atmosphere between the two walls. No heat exchanger will be permitted on any boiler system operating in excess of 65 psi (448.2 kPa), or high temperature hot water system operating in excess of 250°F (121°C), or any steam boiler operating with a pressure in excess of 50 psi (344.75 kPa), unless:
1. The heat exchanger is double-walled;
2. The heat exchanger has an air gap open to the atmosphere between the two walls; and
3. The heat exchanger has a pressure gradient monitor system with a "fail-safe to off" switch installed to isolate the heat exchanger from the potable cold or hot water system. If pressure on the potable water side reaches less than 20 psi (137.9 kPa) above the pressure of the transfer fluid or steam, and a pressure reducing valve is installed on the inlet to the heat exchanger with a setting of 20 psi (137.9 kPa) lower than the potable water pressure at the heat exchanger, an audible alarm shall be activated and the heat exchanger shall be automatically shut off until the alarm and the heat exchanger can be reset manually. Any boiler using toxic chemicals shall have a label with a minimum size of 5 inches by 5 inches (125 mm by 125 mm) attached to the boiler in a conspicuous place. The label shall read as follows:
WARNING Chemicals and additives used to treat the boiler feed water in this boiler are not approved for potable water. The steam or hot water produced by this boiler is not potable. If the steam or hot water produced by this boiler is used to heat water, the water will not be considered potable if the steam and potable water are mixed.
Municipal Code of Chicago § 18-29-502.1 General.
18-29-502.1 General.
Water heaters shall be installed in accordance with the manufacturer's instructions. Gas and oil-fired water heaters shall conform to the requirements of this chapter and the Chicago Mechanical Code. Electric water heaters shall conform to the requirements of this chapter and the Chicago Electrical Code.
(Amend Coun. J. 10-14-21, p. 37722, Art. V, § 3)
Municipal Code of Chicago § 18-29-502.2 Water heaters installed in non-private garages.
18-29-502.2 Water heaters installed in non-private garages.
No direct fired water heater shall be installed in any non-private garage (as defined in Chapter 14B-2).
(Amend Coun. J. 4-10-19, p. 100029, Art. XVI, § 11)
Municipal Code of Chicago § 18-29-502.3 Rooms used as a plenum.
18-29-502.3 Rooms used as a plenum.
Water heaters using solid, liquid or gas fuel shall not be installed in a room containing air-handling machinery when such room is used as a plenum.
Municipal Code of Chicago § 18-29-502.4 Prohibited location.
18-29-502.4 Prohibited location.
Fuel-fired water heaters shall not be installed in any of the following locations: a sleeping room; a bathroom; an attic space; a garage or above any ceiling.
(Amend Coun. J. 3-27-02, p. 82090, § 3)
Municipal Code of Chicago § 18-29-502.5 Water heaters installed in closets accessed through sleeping rooms or bathrooms.
18-29-502.5 Water heaters installed in closets accessed through sleeping rooms or bathrooms.
Water heaters may be installed in closets located in sleeping rooms or bedrooms provided that the closet is equipped with a weather-stripped, self-closing, solid door and all air for combustion and dilution is obtained from the outdoors.
Municipal Code of Chicago § 18-29-502.6 Water heaters installed in attics, basements or other areas.
18-29-502.6 Water heaters installed in attics, basements or other areas.
Areas containing a water heater shall be provided with an opening and unobstructed passageway large enough to allow removal of the water heater. The passageway shall not be less than 30 inches (762 mm) high and 22 inches (559 mm) wide and not more than 20 feet (6.1 m) in length when measured along the centerline of the passageway from the opening to the water heater. The passageway shall have continuous solid flooring not less than 24 inches (610 mm) wide. A level service space at least 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present at the front or service side of the water heater. The clear access opening dimensions shall be a minimum of 20 inches by 30 inches (508 mm by 762 mm) where such dimensions are large enough to allow removal of the water heater.
Municipal Code of Chicago § 18-29-503.1 Cold water line valve.
18-29-503.1 Cold water line valve.
The cold water branch line from the main water supply line to each hot water storage tank or water heater shall be provided with a valve accessible on the same floor, located near the equipment and only serving the hot water storage tank or water heater. The valving shall not interfere or cause a disruption of the cold water supply to the remainder of the cold water system.
Municipal Code of Chicago § 18-29-503.1.1 Shutoff valves.
18-29-503.1.1 Shutoff valves.
Shutoff valves for water heaters or heated water storage tanks shall be allowed to be installed on the inlet side or outlet side or both.
(Amend Coun. J. 6-17-26, p. 45214, Art. IV, § 53)
Municipal Code of Chicago § 18-29-503.2 Deliberately omitted.
Municipal Code of Chicago § 18-29-504.1 Antisiphon devices.
18-29-504.1 Antisiphon devices.
An approved means shall be provided to prevent siphoning of any storage water heater or tank. A cold water "dip" tube with a hole at the top or a vacuum relief valve installed in the cold water supply line above the top of the heater or tank shall be approved for this purpose. Such a device shall be installed on any water heater or heated water storage tank that supplies a water outlet below the level of the heater.
Municipal Code of Chicago § 18-29-504.2 Vacuum relief valve.
18-29-504.2 Vacuum relief valve.
Water heaters elevated above the fixtures they serve and tanks connected to such water heaters shall have a vacuum relief valve installed. The vacuum relief valve shall comply with ANSI Z21.22.
(Amend Coun. J. 3-27-02, p. 82090, § 3)
Municipal Code of Chicago § 18-29-504.3 Energy cutoff device.
18-29-504.3 Energy cutoff device.
All automatically controlled water heaters shall be equipped with an energy cutoff device that will cut off the supply of heat energy to the water tank before the temperature of the water in the tank exceeds 200°F (93.3°C). This cutoff device shall be required in addition to the temperature and pressure relief valves.
Municipal Code of Chicago § 18-29-504.4 Shutdown.
18-29-504.4 Shutdown.
A separate switch shall be provided to terminate the energy supplied to electric hot water supply systems. A separate valve shall be provided to turn off the energy supplied to the main burner of all other types of hot water supply systems.
Municipal Code of Chicago § 18-29-504.5 Relief valve.
18-29-504.5 Relief valve.
All storage water heaters operating above atmospheric pressure shall be provided with an approved, self-closing (levered) pressure relief valve and temperature relief valve or combination thereof. The relief valve shall conform to ANSI Z21.22. The relief valve shall not be used as a means of controlling thermal expansion.
Municipal Code of Chicago § 18-29-504.5.1 Installation.
18-29-504.5.1 Installation.
Relief valves shall be installed in the shell of the water heater tank. Temperature relief valves shall be so located in the tank as to be activated by the water in the top 6 inches (150 mm) of the tank served. For installations with separate storage tanks, the valves shall be installed on the tank and there shall not be any type of valve installed between the water heater and the storage tank. There shall not be a check valve or shutoff valve between a relief valve and the heater or tank served.
Municipal Code of Chicago § 18-29-504.6 Relief valve approval.
18-29-504.6 Relief valve approval.
Temperature and pressure relief valves (or combinations thereof) and energy cutoff devices shall bear the label of an approved agency and shall have a temperature setting of not more than 210°F (99°C) and a pressure setting not exceeding the tank or water heater manufacturer’s rated working pressure or 150 psi (1035 kPa), whichever is less. The relieving capacity of each pressure relief valve and each temperature relief valve shall equal or exceed the heat input to the water heater or storage tank.
(Amend Coun. J. 6-17-26, p. 45214, Art. IV, § 54)
Municipal Code of Chicago § 18-29-504.7 Relief outlet waste.
18-29-504.7 Relief outlet waste.
The outlet of a pressure, temperature or other relief valve shall not be directly connected to the drainage system.
(Amend Coun. J. 11-9-16, p. 36266, § 37)
Municipal Code of Chicago § 18-29-504.7.1 Discharge.
18-29-504.7.1 Discharge.
The discharge from the relief valve shall be piped separately to an indirect waste receptor located inside the building. The discharge shall be piped full size and installed in a manner that does not cause personal injury or property damage and that is readily observable by the building occupants. The discharge from a relief valve shall not be trapped. The diameter of the discharge piping shall not be less than the diameter of the relief valve outlet. The discharge pipe shall be installed so as to drain by gravity flow and shall terminate atmospherically not more than 6 inches (150 mm) above the floor. The end of the discharge pipe shall not be threaded.
Municipal Code of Chicago § 18-29-504.7.2 Location.
18-29-504.7.2 Location.
The relief outlet discharge piping shall be installed so that it does not leave the room or enclosure in which the water heater and relief valve are located.
Municipal Code of Chicago § 18-29-504.7.3 Materials.
18-29-504.7.3 Materials.
Relief valve discharge piping shall be of those materials listed in Section 18-29-605.5 for water distribution piping or shall be tested, rated and approved for such use in accordance with ASME A112.4.1. Piping from safety pan drains shall be of those materials listed in Table 18-29-605.5.
Municipal Code of Chicago § 18-29-504.8 Required pan.
18-29-504.8 Required pan.
Where a storage-tank type water heater or a hot water storage tank is installed in a location where water leakage from the tank will cause damage, the tank shall be installed in a pan constructed of one of the following:
1. Galvanized steel or aluminum of not less than 0.0236 inch (0.6010 mm) in thickness.
2. Plastic not less than 0.036 inch (0.9 mm) in thickness. (A plastic pan shall not be installed beneath a gas-fired water heater.)
(Amend Coun. J. 3-27-02, p. 82090, § 3; Amend Coun. J. 10-14-21, p. 37722, Art. V, § 4)
Municipal Code of Chicago § 18-29-504.8.1 Pan size and drain.
18-29-504.8.1 Pan size and drain.
The pan shall not be less than 1 1/2 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 3/4 inch (19 mm) or the outlet diameter of the required relief valve, whichever is larger.
(Amend Coun. J. 10-14-21, p. 37722, Art. V, § 4)
Municipal Code of Chicago § 18-29-504.8.2 Pan drain termination.
18-29-504.8.2 Pan drain termination.
The pan drain shall extend full-size and terminate over a suitably located indirect waste receptor or floor drain. Where a pan drain was not previously installed, a pan drain shall not be required for a replacement water heater installation.
(Amend Coun. J. 10-14-21, p. 37722, Art. V, § 4)
Municipal Code of Chicago § 18-29-505.1 Unfired vessel insulation.
18-29-505.1 Unfired vessel insulation.
Unfired hot water storage tanks shall be insulated to R-12.5 (h × ft 2 × °F) / Btu (R-2.2 m 2 × K/W).
(Amend Coun. J. 10-14-21, p. 37722, Art. V, § 5)
Source: City of Chicago, Municipal Code of Chicago (American Legal Publishing, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/chicago/latest/chicago_il/0-0-0-2691260Fetched: 10/24/2026