CPC · California Plumbing Code
What pressure- and temperature-limiting devices are required?
Homeowner summary: California requires every water heater to have a listed pressure‑relief valve set above your incoming water pressure but no higher than 150 psi, and a listed overtemperature (high‑limit) device; both must be installed per the device and heater manufacturer instructions so the heater is protected and discharge piping remains unobstructed.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Water heater installations must have both overpressure protection and overtemperature protection using approved, listed devices installed per their listing and the manufacturer’s instructions. The pressure device must be set greater than the water service pressure and not exceed 150 psi (1034 kPa) — see § 504.4. Overtemperature (high‑limit) protection is required for water heaters and hot water storage vessels — see § 504.5.
The single most important point: install a listed pressure‑relief device set above the incoming service pressure but ≤ 150 psi, and install a listed overtemperature device — both must be installed in accordance with their listings and the manufacturer’s instructions.
Requirements in detail
Short plain-English summary of each device
- Overpressure protection (pressure‑limiting device) — required on every water heater installation; must be an approved, listed device; pressure setting > water service pressure and ≤ 150 psi. § 504.4.
- Overtemperature protection (temperature‑limiting device) — required on every water heater installation and hot water storage vessel; must be an approved, listed device installed per its listing/manufacturer’s instructions. § 504.5.
Decision‑relevant dimensions & values
| Item | Decision / Value | Code Reference |
|---|---|---|
| Required device for overpressure protection | Approved, listed device (pressure relief or equivalent) | § 504.4 |
| Pressure setting requirement | Greater than the water service pressure and not exceed 150 psi (1034 kPa) | § 504.4 |
| Required device for overtemperature protection | Approved, listed device (overtemperature safety) | § 504.5 |
| Installation location / method | Installed per the terms of the device’s listing and the manufacturer’s installation instructions | § 504.4, § 504.5 |
| Prohibition on shutoff between relief device and heater | No shutoff valve may be placed between the relief valve and the water heater (and on discharge piping to atmosphere) | § 504.6 |
| Relief device capacity | Discharge capacity must be not less than the input rating of the water heater | § 504.6 |
| Discharge piping requirements | Discharge piping shall be installed in accordance with § 608.5 | § 504.6; see § 608.5 |
(Notes: § 504.6 contains closely related rules on temperature/pressure relief devices, discharge capacity, and prohibition of isolation valves between device and heater; these are necessary to make the pressure/temperature protection effective.)
Exceptions & special cases
- The CPC text for § 504.4 and § 504.5 requires listed/approved devices and installation per listing; it does not list numeric trip temperatures for overtemperature devices in these sections. If a product standard or the appliance listing specifies specific trip settings or additional requirements, follow those. § 504.5 requires a listed overtemperature device but defers details to the device listing/manufacturer.
- Combination devices (temperature, pressure and vacuum relief devices) and automatic gas shutoff devices are governed by § 504.6 and must be installed per their listings; do not insert a shutoff valve between the device and the water heater.
- For product standards and acceptable device types (e.g., ASSE/ANSI standards for temperature‑limiting mixing valves and water‑heater related devices), consult the CPC referenced‑standards tables (see the CPC referenced‑standards table entries for water temperature limiting devices). The CPC requires listed devices but points to referenced standards for specific device standards.
If a specific local Authority Having Jurisdiction (AHJ) approval or additional requirements exist (for example for unlisted heaters or special installations), follow the AHJ direction — the CPC language requires that unlisted appliances be approved by the AHJ where applicable.
Common mistakes
- Setting the pressure‑relief valve at or below the incoming water service pressure (it must be set greater than service pressure) — violates § 504.4.
- Choosing a relief device with a maximum setting over 150 psi (the code caps the setting at 150 psi) — violates § 504.4.
- Installing a shutoff valve between the relief device and the water heater or on discharge piping to atmosphere — prohibited by § 504.6.
- Using an unlisted or otherwise non‑approved device, or failing to follow the device’s listing/manufacturer instructions — the CPC requires approved, listed devices and installation per listing/instructions (both § 504.4 and § 504.5).
- Forgetting to verify relief device capacity relative to heater input: the device’s discharge capacity must be not less than the input rating of the heater (see § 504.6).
Worked example — concrete scenario
Scenario: A single‑family home has a storage water heater served by a municipal water supply with a measured service pressure of 80 psi. The heater manufacturer’s installation instructions call for a temperature high‑limit device and a pressure relief device per appliance listing.
Applying the CPC rules:
- Pressure device: select a listed pressure‑relief device and set it above the measured water service pressure (80 psi) but not over 150 psi. For example, a relief device with a nominal setting of 100 psi meets § 504.4 because 100 psi > 80 psi and ≤ 150 psi. § 504.4
- Temperature device: install the listed overtemperature (high‑limit) device provided or required by the appliance, and install it per the device listing and the manufacturer’s instructions, satisfying § 504.5. The CPC text does not prescribe a single trip temperature here — the device must be listed and installed per its listing/manufacturer. § 504.5
- Do not install any shutoff valve between the relief device and the heater; size discharge piping and confirm relief device discharge capacity per § 504.6 and § 608.5.
Related provisions
- § 504.6 — Temperature, pressure, and vacuum relief device installation rules; prohibition on shutoff valve between relief valve and water heater; discharge capacity >= input rating; discharge piping per § 608.5.
- § 608.4 — (Referenced by § 504.4) pressure limit language (cited in § 504.4 concerning 150 psi).
- § 608.5 — Relief valve discharge piping installation requirements (see § 504.6).
- § 505.2 — Safety devices required for non‑gas (fuel) water heaters, including overtemperature protection and combination temperature and pressure relief valves (where applicable).
- Referenced standards table (Table 1701.1 / referenced standards) — identifies product standards (e.g., ASSE/ANSI) for temperature limiting devices and water‑heater related devices; consult when selecting listed devices.
Code references
Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:
CPC § 54-2018 High relevance — show source text
Clearance for unlisted water heaters shall be not less than 12 inches (305 mm) on all sides. Combustible floors under unlisted water heaters shall be protected in an approved manner. {NFPA 54-2018:10.27.2.2} 504.4 Pressure-Limiting Devices. A water heater installation shall be provided with overpressure protection using an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. Pressure relief devices shall have a pressure setting greater than the water service pressure and not exceed 150 psi (1034 kPa) as required in Section 608.4. 504.5 Temperature Limiting Devices. A water heater installation or a hot water storage vessel installation shall be provided with overtemperature protection by means of an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. {NFPA 54:10.26.5} 504.6 Temperature, Pressure, and Vacuum Relief Devices. Temperature, pressure, and vacuum relief devices or combinations thereof, and automatic gas shutoff devices shall be installed in accordance with the terms of their listings and the manufacturer’s installation instructions. A shutoff valve shall not be placed between the relief valve and the water heater or on discharge pipes between such valves and the atmosphere. The hourly British thermal units (Btu) (kW•h) discharge capacity or the rated steam relief capacity of the device shall be not less than the input rating of the water heater. {NFPA 54:10.26.6} Discharge piping shall be installed in accordance with Section 608.5.
504.7 Lead Content. Water heaters shall comply with the lead content requirements of Section 604.2.
505.0 Oil-Burning and Other Water Heaters. 505.1 Water Heaters. Water heaters deriving heat from fuels or types of energy other than gas shall comply with the standards referenced in Table 501.1(1), Section 505.3, or Section 505.4. Vents or chimneys for such appliances shall be of approved types. An adequate supply of air for combustion and for adequate ventilation of heater rooms or compartments shall be provided. Each such appliance shall be installed in a
location approved by the Authority Having Jurisdiction and local and state fire-prevention agencies. 505.2 Safety Devices. Storage-type water heaters and hot water boilers deriving heat from fuels or types of energy other than gas, shall be provided with, in addition to the primary temperature controls, an over-temperature safety protection device that complies with and is installed in accordance with nationally recognized applicable standards for such devices and a combination temperature and pressure-relief valve.
505.3 Oil-Fired Water Heaters. Oil-fired water heaters
shall be installed in accordance with NFPA 31.
505.4 Indirect-Fired Water Heaters. Indirect-fired water heaters shall be in accordance with the applicable sections of the ASME Boiler and Pressure Vessel Code or shall comply with one of the other applicable standards shown in Table 501.1(1). Each water heater shall bear a label in accordance with ASME requirements, or an approved testing agency, certifying and attesting that such an appliance has been tested, inspected and meets the requirements of the applicable standards or code. 505.4.1 Single-Wall Heat Exchanger. An indirectfired water heater that incorporates a single-wall heat exchanger shall be in accordance with the following requirements:
CPC § 3.785 High relevance — show source text
For SI units: 1 gallon = 3.785 L
Notes: 1 The first-hour rating is found on the “Energy Guide” label. 2 Solar water heaters shall be sized to meet the appropriate first-hour rating as shown in the table.
2025 CALIFORNIA PLUMBING CODE 83
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
WATER HEATERS
Exception: Where acceptable to the Authority Having Jurisdiction, gasketing of non-combustible or limitedcombustible material shall be permitted to be applied to the frame, provided closing and latching of the door are not inhibited.
504.2 Vent. Water heaters of other than the direct-vent type shall be located as close as practical to the chimney or gas vent. 504.3 Clearance. The clearance requirements for water heaters shall comply with Section 504.3.1 or Section 504.3.2.
504.3.1 Listed Water Heaters. The clearances shall not be such as to interfere with combustion air, draft hood clearance and relief, and accessibility for servicing. Listed water heaters shall be installed in accordance with their listings and the manufacturer’s installation instructions. 504.3.2 Unlisted Water Heaters. Except as otherwise permitted in this code, unlisted water heaters shall be approved by the Authority Having Jurisdiction prior to being installed. Clearance for unlisted water heaters shall be not less than 12 inches (305 mm) on all sides. Combustible floors under unlisted water heaters shall be protected in an approved manner. {NFPA 54-2018:10.27.2.2} 504.4 Pressure-Limiting Devices. A water heater installation shall be provided with overpressure protection using an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. Pressure relief devices shall have a pressure setting greater than the water service pressure and not exceed 150 psi (1034 kPa) as required in Section 608.4. 504.5 Temperature Limiting Devices. A water heater installation or a hot water storage vessel installation shall be provided with overtemperature protection by means of an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. {NFPA 54:10.26.5} 504.6 Temperature, Pressure, and Vacuum Relief Devices. Temperature, pressure, and vacuum relief devices or combinations thereof, and automatic gas shutoff devices shall be installed in accordance with the terms of their listings and the manufacturer’s installation instructions. A shutoff valve shall not be placed between the relief valve and the water heater or on discharge pipes between such valves and the atmosphere. The hourly British thermal units (Btu) (kW•h) discharge capacity or the rated steam relief capacity of the device shall be not less than the input rating of the water heater. {NFPA 54:10.26.6} Discharge piping shall be installed in accordance with Section 608.5.
504.7 Lead Content. Water heaters shall comply with the lead content requirements of Section 604.2.
CPC § 505.0 High relevance — show source text
Oil-burning and other . . . . . . . . . . . . . . . . . . . . . .505.0 Permits required . . . . . . . . . . . . . . . . . . . . . . . . . .502.0
Pressure-relief valves . . . . . . . . . . .504.4, 504.6, 505.2,
608.2 – 608.5
Protection . . . . . . . . . . . . . . . . . . .504.3 – 504.6, 505.2,
507.2, 507.8, 507.10,
507.14.1, 507.24
Relief valve discharge . . . . . . . . . . . . . . . . . . . . . .608.5 Seismic provisions . . . . . . . . . . . . . . . . . . . . . . . . .507.2 Temperature and pressure-relief valves . . . . . . . . . . . . . . .504.6, 505.2 Temperature-limiting devices . . . . . . . . . . . . . . . . .504.5
Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . .509.0, 510.0
Water heating system requirements . . . . . . . . . . . .501.2 WATER SOFTENERS . . . . . . . . . . . . . . . . 611.4, Table 611.4
WATER STATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .225.0
WATER TESTS
Building sewers . . . . . . . . . . . . . . . . . . . . . . . . . . .723.0 Drainage and vent systems . . . . . . . . . . . . .105.3, 712.2 Storm drainage . . . . . . . . . . . . . . . . . .1107.2.1, 1107.2.3 Water supply systems . . . . . . . .105.2.1.1, 105.3, 609.4
WATERPROOFING
AND WATERTIGHT
Building sewer . . . . . . . . . . . . . . . . . . . . . . . . . . . .723.1
Cleanouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .707.3
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105.3
Drain pans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .507.5
Fixtures . . . . . . . . . . . . . . . . .402.2, 408.6, 408.8, 418.2
CPC § 408.8 High relevance — show source text
Exceptions:
(1) Showers that are designed to be in accordance with Chapter 11A of the California Building Code .
(2) The minimum required area and dimension shall not apply for a shower receptor having overall dimensions of not less than 30 inches (762 mm) in width and 60 inches (1524 mm) in length. 408.8 Lining for Showers and Receptors. Shower receptors built on-site shall be watertight and shall be constructed from approved-type dense, nonabsorbent, and noncorrosive materials. Each such receptor shall be adequately reinforced, shall be provided with an approved flanged floor drain designed to make a watertight joint on the floor, and shall have smooth, impervious, and durable surfaces.
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408.3.2 Multiple Showerheads Serving One Shower. [BSC-CG & DSA-SS] When a shower is served by more than one showerhead, the combined flow rate of all showerheads and/or other shower outlets controlled by a single valve shall not exceed 1.8 gallons (6.81 L) per minute at 80 psi, or the shower shall be designed to allow only one shower outlet to be in operation at a time in com- pliance with Chapter 5, Division 5.3 of the California Green Building Standards Code (CALGreen).
Note: A hand-held shower shall be considered a show-
erhead.
408.4 Individual Shower and Tub-Shower Combina-
tion Control Valves. Showers and tub-shower combinations shall be provided with individual control valves of the pressure balance, thermostatic, or combination pressure balance/thermostatic mixing valve type that provide scald and thermal shock protection for the rated flow rate of the installed showerhead. These valves shall be installed at the point of use and comply with ASSE 1016/ASME A112.1016/CSA B125.16 or ASME A112.18.1/CSA B125.1.
408.4.1 Gang Showers. Where gang showers are supplied with a single temperature-controlled water supply pipe, it shall be controlled by a mixing valve that complies with ASSE 1069.
408.4.2 Temperature Limiting. The maximum water temperature discharging from an individual showerhead shall be limited to 120°F (49°C) by one of the following methods:
(1) A shower or tub/shower combination valve conforming to ASSE 1016/ASME A112.1016/CSA B125.16 where either:
(a) The valve is field-adjusted to the required maximum temperature, or
(b) The handle position, stop, or temperature limiting control is set in accordance with the manufacturer’s instructions to the required maximum temperature.
(2) For gang showers supplied by a single water supply pipe, a mixing valve that conforms to ASSE 1069 that is field-adjusted to the required maximum temperature.
408.4.3 Temperature-Actuated, Flow-Reduction Devices for Individual Fixture Fittings. Temperature-actuated, flow-reduction devices, where installed for individual fixture fittings, shall comply with ASSE 1062. Such devices shall not be used alone as a substitute for the balanced pressure, thermostatic or combination shower valves requirements or as a substitute for bathtub or whirlpool tub water temperature-limiting valves requirements.
CPC § 507.25 High relevance — show source text
507.25, 508.4
Approval requirements . . . . . . . . . . . . . . . . . . . . . .501.1 Approved standards . . . . . .Table 501.1(1), 505.3, 505.4 Clearances. . . . . . . . . . . . . . . . . . . . . . 504.3 – 504.3.2,
508.1, 508.2.1
Combustion air required . . . . . . . . . . . . . . . . . . . .506.0
Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . .604.13
Dual purpose, definition . . . . . . . . . . . . . . . . . . . .225.0
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .225.0
Garages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .507.13 Inspections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .503.2
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .507.0
Location . . . . . . . . . . . . . . . . . . .504.1, 507.12 – 507.15
Oil-burning and other . . . . . . . . . . . . . . . . . . . . . .505.0 Permits required . . . . . . . . . . . . . . . . . . . . . . . . . .502.0
Pressure-relief valves . . . . . . . . . . .504.4, 504.6, 505.2,
608.2 – 608.5
Protection . . . . . . . . . . . . . . . . . . .504.3 – 504.6, 505.2,
507.2, 507.8, 507.10,
507.14.1, 507.24
Relief valve discharge . . . . . . . . . . . . . . . . . . . . . .608.5 Seismic provisions . . . . . . . . . . . . . . . . . . . . . . . . .507.2 Temperature and pressure-relief valves . . . . . . . . . . . . . . .504.6, 505.2 Temperature-limiting devices . . . . . . . . . . . . . . . . .504.5
Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . .509.0, 510.0
Water heating system requirements . . . . . . . . . . . .501.2 WATER SOFTENERS . . . . . . . . . . . . . . . . 611.4, Table 611.4
CPC § 501.1 High relevance — show source text
Table 501.1(1) Water Heaters . . . . . . . . . . . . . . . .83
501.2 California Energy Code Water Heating System Requirements . . . . . . . . . . . . . . . . .83
502.0 Permits . . . . . . . . . . . . . . . . . . . . . .83
502.1 General . . . . . . . . . . . . . . . . . . . . . .83
503.0 Inspection . . . . . . . . . . . . . . . . . . . .83
503.1 Inspection of Chimneys or Vents . . .83
503.2 Final Water Heater Inspection . . . .83
504.0 Water Heater Requirements . . . . . .83
504.1 Location . . . . . . . . . . . . . . . . . . . . .83
Table 501.1(2) First Hour Rating . . . . . . . . . . . . . .83
504.2 Vent . . . . . . . . . . . . . . . . . . . . . . . .84
504.3 Clearance . . . . . . . . . . . . . . . . . . . .84
504.4 Pressure-Limiting Devices . . . . . . .84
504.5 Temperature-Limiting Devices . . . .84
504.6 Temperature, Pressure, and Vacuum Relief Devices . . . . . . . . .84
504.7 Lead Content . . . . . . . . . . . . . . . . .84
505.0 Oil-Burning and Other Water Heaters . . . . . . . . . . . . . . . . . . . . . .84
505.1 Water Heaters . . . . . . . . . . . . . . . .84
505.2 Safety Devices . . . . . . . . . . . . . . . .84
505.3 Oil-Fired Water Heaters . . . . . . . . .84
505.4 Indirect-Fired Water Heaters . . . . .84
506.0 Air for Combustion and
Ventilation . . . . . . . . . . . . . . . . . . . .84
506.1 General . . . . . . . . . . . . . . . . . . . . . .84
506.2 Indoor Combustion Air . . . . . . . . . .85
506.3 Indoor Opening Size and Location . . . . . . . . . . . . . . . . . . . . .85
506.4 Outdoor Combustion Air . . . . . . . . .85
506.5 Combination Indoor and
Outdoor Combustion Air . . . . . . . . .87
506.6 Engineered Installations . . . . . . . . .87
506.7 Mechanical Combustion Air Supply . . . . . . . . . . . . . . . . . . . . . . .87
506.8 Louvers, Grilles, and Screens . . . .87
506.9 Combustion Air Ducts . . . . . . . . . . .87
507.0 Appliance and Equipment Installation Requirements . . . . . . . .88
507.1 Dielectric Insulator . . . . . . . . . . . . .88
CPC § 49.9 High relevance — show source text
** Systems containing more than 110 pounds (49.9 kg) of refrigerant shall have stop valves installed at the following locations: (1) The suction inlet of each compressor, compressor unit, or condensing unit. (2) The discharge outlet of each compressor, compressor unit, or condensing unit. (3) The inlet of each liquid receiver, except for self-contained systems or where the receiver is an integral part of the condenser or condensing unit. (4) The outlet of each liquid receiver. (5) The inlets and outlets of condensers when more than one condenser is used in parallel in the system. Exceptions: (1) Systems that have a refrigerant pumpout function capable of storing entire the refrigerant charge.
(2) Systems that are equipped with the provisions for pumpout of the refrigerant.
(3) Self-contained systems. [ASHRAE 15:9.12.5] 1110.3 Support. Stop valves installed in copper refrigerant lines of [3] ⁄ 4 of an inch (20 mm) or less outside diameter shall be supported independently of the tubing or piping.
1110.4 Access. Stop valves required by Section 1110.0 shall be readily accessible from the refrigeration machinery room floor or a level platform.
1110.5 Identification. Stop valves shall be identified by tagging in accordance with the reference standard for identification. A valve chart shall be mounted under glass at an approved location near the principal entrance to a refrigeration machinery room.
1111.0 Pressure-Limiting Devices.
1111.1 Where Required. Pressure-limiting devices complying with Section 1111.2 through Section 1111.4 shall be provided for compressors on all systems operating above atmospheric pressure.
Exception: Pressure limiting devices are not required for listed factory-sealed systems containing less than 22 pounds (9.9 kg) of Group A1 refrigerant. [ASHRAE 15:9.9.1] 1111.2 Setting. Pressure limiting devices shall be set in accordance with one the following:
(1) For positive displacement compressors:
(a) When systems are protected by a highside pressure relief device, the compressor’s pressure limiting device shall be set not more than 90 percent of the operating pressure for the highside pressure relief device.
(b) When systems are not protected by a highside pressure relief device, the compressor’s pressure limiting device shall be set not more than the system’s highside design pressure.
(2) For nonpositive displacement compressors:
(a) When systems are protected by a highside pressure relief device, the compressor’s pressure limiting device shall be set not more than 90 percent of the operating pressure for the highside pressure relief device.
(b) When systems are protected by a lowside pressure relief device that is only subject to lowside pressure, and is provided with a permanent relief path between the systems’ highside and lowside, without intervening valves, the compressor’s pressure limiting device shall be set not more than the systems’ highside design pressure. [ASHRAE 15:9.9.2]
1111.3 Location. Stop valves shall not be installed between the pressure imposing element and pressure limiting devices serving compressors. [ASHRAE 15:9.9.3] 1111.4 Emergency Stop. Activation of a pressure-limiting device shall stop the action of the pressure-imposing element.
[ASHRAE 15:9.9.4]
CPC § 408.4.1 High relevance — show source text
408.4.1 Gang Showers. Where gang showers are supplied with a single temperature-controlled water supply pipe, it shall be controlled by a mixing valve that complies with ASSE 1069.
408.4.2 Temperature Limiting. The maximum water temperature discharging from an individual showerhead shall be limited to 120°F (49°C) by one of the following methods:
(1) A shower or tub/shower combination valve conforming to ASSE 1016/ASME A112.1016/CSA B125.16 where either:
(a) The valve is field-adjusted to the required maximum temperature, or
(b) The handle position, stop, or temperature limiting control is set in accordance with the manufacturer’s instructions to the required maximum temperature.
(2) For gang showers supplied by a single water supply pipe, a mixing valve that conforms to ASSE 1069 that is field-adjusted to the required maximum temperature.
408.4.3 Temperature-Actuated, Flow-Reduction Devices for Individual Fixture Fittings. Temperature-actuated, flow-reduction devices, where installed for individual fixture fittings, shall comply with ASSE 1062. Such devices shall not be used alone as a substitute for the balanced pressure, thermostatic or combination shower valves requirements or as a substitute for bathtub or whirlpool tub water temperature-limiting valves requirements.
408.5 Waste Outlet. Showers shall have a waste outlet and fixture tailpiece not less than 2 inches (50 mm) in diameter. Fixture tailpieces shall be constructed from the materials specified in Section 701.2 for drainage piping. Strainers serving shower drains shall comply with ASME A112.18.2/CSA B125.2.
62 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
PLUMBING FIXTURES AND FIXTURE FITTINGS
shall be insulated from conducting substances, other than the connecting drain, by 15 pound (6.8 kg) asphalt felt or an equivalent. Sheet lead shall be joined by burning. 408.8.4 Sheet Copper. Sheet copper shall comply with ASTM B152 and shall weigh not less than 12 ounces per square foot (oz/ft [2] ) (3.7 kg/m [2] ) or No. 24 B & S Gauge (0.02 inches) (0.51 mm). The copper sheet shall be insulated from conducting substances, other than the connecting drain, by 15 pound (6.8 kg) asphalt felt or an equivalent. Sheet copper shall be joined by brazing or soldering. 408.8.5 Tests for Shower Receptors. Shower receptors shall be tested for watertightness by filling with water to a depth of not less than 2 inches (51 mm) for not less than 15 minutes. Where no threshold is present, a 2 inch (51 mm) barrier shall be temporarily constructed for testing. The test plug shall be so placed that both upper and under sides of the subpan shall be subjected to the test at the point where it is clamped to the drain. 408.9 Public Shower Floors. Floors of public shower rooms shall have a nonskid surface and shall be drained in such a manner that wastewater from one bather shall not pass over areas occupied by other bathers.
CPC § 160.2 Medium relevance — show source text
A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
4. Unitary system serving one dwelling unit
5. Central system serving multiple dwelling units|1. Requirements only apply when using Balanced Ventilation to meet 160.2(b)2Aivb.
2. HSPF2 means “heating seasonal performance factor.”
3. A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
4. Unitary system serving one dwelling unit
5. Central system serving multiple dwelling units|1. Requirements only apply when using Balanced Ventilation to meet 160.2(b)2Aivb.
2. HSPF2 means “heating seasonal performance factor.”
3. A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
4. Unitary system serving one dwelling unit
5. Central system serving multiple dwelling units|1. Requirements only apply when using Balanced Ventilation to meet 160.2(b)2Aivb.
2. HSPF2 means “heating seasonal performance factor.”
3. A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
4. Unitary system serving one dwelling unit
5. Central system serving multiple dwelling units|1. Requirements only apply when using Balanced Ventilation to meet 160.2(b)2Aivb.
2. HSPF2 means “heating seasonal performance factor.”
3. A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
4. Unitary system serving one dwelling unit
5. Central system serving multiple dwelling units|1. Requirements only apply when using Balanced Ventilation to meet 160.2(b)2Aivb.
2. HSPF2 means “heating seasonal performance factor.”
3. A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
4. Unitary system serving one dwelling unit
5. Central system serving multiple dwelling units|1. Requirements only apply when using Balanced Ventilation to meet 160.2(b)2Aivb.
2. HSPF2 means “heating seasonal performance factor.”
3.CPC § 422.1 Medium relevance — show source text
422.1 Fixture Count . . . . . . . . . . . . . . . . .67
422.2 Separate Facilities . . . . . . . . . . . . .68
422.3 Fixture Requirements for Special Occupancies . . . . . . . . . . .68
422.4 Toilet Facilities Serving Employees and Customers . . . . . .68
422.5 Toilet Facilities for Workers . . . . . .69
422.6 Water Closet Compartment . . . . . .69
422.7 Urinal Partitions . . . . . . . . . . . . . . .69
422.8 Cosmetology . . . . . . . . . . . . . . . . .69
422.9 Cosmetology Establishments . . . . .69
422.10 Commissaries Serving Mobile Food Preparation Units . . . . . . . . .69
422.11 Employee Lavatories in Food Establishments . . . . . . . . . . .69
Table 422.1 Minimum Plumbing Facilities . . . . .70
Table 4-1 Occupant Load Factor
[BSC and DSA-SS] . . . . . . . . . . . .75
Table 4-2 Minimum Plumbing Facilities
[OSHPD 1, 2, 3, 4 & 5] . . . . . . . . .76
CHAPTER 5 WATER HEATERS . . . . . . . . . . . .81
501.0 General . . . . . . . . . . . . . . . . . . . . . .83
501.1 Applicability . . . . . . . . . . . . . . . . . . .83
Table 501.1(1) Water Heaters . . . . . . . . . . . . . . . .83
501.2 California Energy Code Water Heating System Requirements . . . . . . . . . . . . . . . . .83
502.0 Permits . . . . . . . . . . . . . . . . . . . . . .83
502.1 General . . . . . . . . . . . . . . . . . . . . . .83
503.0 Inspection . . . . . . . . . . . . . . . . . . . .83
503.1 Inspection of Chimneys or Vents . . .83
503.2 Final Water Heater Inspection . . . .83
504.0 Water Heater Requirements . . . . . .83
504.1 Location . . . . . . . . . . . . . . . . . . . . .83
Table 501.1(2) First Hour Rating . . . . . . . . . . . . . .83
504.2 Vent . . . . . . . . . . . . . . . . . . . . . . . .84
504.3 Clearance . . . . . . . . . . . . . . . . . . . .84
504.4 Pressure-Limiting Devices . . . . . . .84
504.5 Temperature-Limiting Devices . . . .84
504.6 Temperature, Pressure, and Vacuum Relief Devices . . . . . . . . .84
504.7 Lead Content . . . . . . . . . . . . . . . . .84
CPC § 1208.9 Medium relevance — show source text
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1208.9 Overpressure Protection Devices. Overpressure protection devices shall be one of the following:
(1) Pressure relief valve.
(2) Monitor regulator.
(3) Series regulator installed upstream from the line regulator and set to continuously limit the pressure on the inlet of the line regulator to the maximum values specified by Section 1208.10 or less.
(4) Automatic shutoff device installed in series with the line pressure regulator and set to shut off when the pressure on the downstream piping system reaches the maximum values specified by Section 1208.10 or less. This device shall be designed so that it will remain closed until manually reset. [NFPA 54:5.8.3.1] 1208.9.1 Separate Devices. The devices in Section 1208.9 shall be installed either as an integral part of the service or line pressure regulator or as separate units. Where separate overpressure protection devices are installed, they shall comply with Section 1208.9.2 through Section 1208.9.7. [NFPA 54:5.8.3.2]
1208.9.2 Construction and Installation. All overpressure protection devices shall meet the following requirements:
(1) Be constructed of materials so that the operation of the device is not impaired by corrosion of external parts by the atmosphere or of internal parts by the gas.
(2) Be designed and installed so they can be operated to determine whether the valve is free. The devices shall also be designed and installed so they can be tested to determine the pressure at which they operate and be examined for leakage when in the closed position. [NFPA 54:5.8.4] 1208.9.3 External Control Piping. External control piping shall be designed and installed so that damage to the control piping of one device does not render both the regulator and the overpressure protective device inoperative. [NFPA 54:5.8.5] 1208.9.4 Setting. Each pressure limiting or pressure relieving device shall be set so that the gas pressure supplied to the connected appliance(s) does not exceed the limits specified in Section 1208.10 and Section 1208.10.1.
[NFPA 54:5.8.6] 1208.9.5 Unauthorized Operation. Where unauthorized operation of any shutoff valve could render a pressure relieving valve or pressure limiting device inoperative, one of the following shall be accomplished:
(1) The valve shall be locked in the open position. Instruct authorized personnel in the importance of leaving the shutoff valve open and of being present while the shutoff valve is closed so that it can be locked in the open position before leaving the premises.
(2) Duplicate relief valves shall be installed, each having adequate capacity to protect the system, and arrange the isolating valves or three-way valve so that only one relief valve can be rendered inoperative at a time. [NFPA 54:5.8.7]
2025 CALIFORNIA PLUMBING CODE 221
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
FUEL GAS PIPING
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CPC § 603.5.2 Medium relevance — show source text
Urinal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .603.5.2
Water closet . . . . . . . . . . . . . . . . .404.2.2, 405.1, 601.2,
603.5.2, 603.5.3, L 402.2
Water supply . . . . . . . . . . . . . . . . . . . . . . .608.1, 608.6, 608.7, E 502.7, E 506.1
TELEPHONE AND DATA
EQUIPMENT ROOMS . . . . . . . . . . . . . . . . . . . . . . .310.15
TEMPERATURE AND
PRESSURE-RELIEF VALVES . . . . . . . . . . . .504.6, 505.2
TEMPERATURE-LIMITING DEVICES . . . . . . .407.3, 408.4,
409.4, 410.3, 504.5
TEMPORARY USE OF GAS . . . . . . . . . . . . . . . . . . .1207.0
TERMINATION OF VENTS . . . . . . . . . . . . . .509.6.1, 509.8
509.8.1, 906.0, H 501.11
TESTING AGENCY, DEFINITION . . . . . . . . . . . . . . . . . 222.0
TESTS
Air . . . . . . . . . . . . .105.3, 105.3.1, 609.4, 712.3, 723.1,
1107.2.2, 1107.2.3, 1213.1.6
Alternate materials and methods . . . . . . . . . . . . . .301.3
Building sewer . . . . . .102.4.1, 105.2.1, 105.2.1.2, 723.0 Cross-connection . . . . . . . . . . . . . . . . 1502.3, 1502.3.2,
1505.14.2, 1505.14.2.2
Exceptions . . . . . . . . . . . . . . . . . . . . . . .105.3, 1107.2.3
Final . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .712.1
Frequently asked questions
What exactly does “approved, listed device” mean here?
It means the device must be listed by an approved testing/listing agency (listed in its product listing) and be installed according to the terms of that listing and the manufacturer’s instructions, as required by § 504.4 and § 504.5.
Can I set the pressure relief at the exact service pressure?
No. § 504.4 requires the relief device setting to be greater than the water service pressure; it also cannot exceed 150 psi.
Is a separate overtemperature device always required if the heater has thermostatic controls?
Yes. The CPC requires overtemperature protection by an approved, listed device for water heaters and hot water storage vessels per § 504.5; follow the appliance listing and manufacturer instructions.
May I install a shutoff valve between the relief valve and the heater for service?
No. § 504.6 expressly prohibits placing a shutoff valve between the relief valve and the water heater or on discharge pipes from the relief valve to the atmosphere.
What if my relief valve’s discharge capacity is smaller than the heater input?
You must provide a relief device whose hourly Btu (or rated steam relief) discharge capacity is not less than the input rating of the water heater, per § 504.6.
More in California Plumbing Code
- Administration
- Definitions
- General Regulations
- Plumbing Fixtures and Fixture Fittings
- Water Heaters
- Water Supply and Distribution
- Sanitary Drainage (Drain, Waste, and Vent)
- Indirect Wastes
- Vents
- Traps and Interceptors
- Storm Drainage
- Fuel Gas Piping
- Health Care Facilities — Medical Gas and Medical Vacuum Systems
- Alternate Water Sources and Nonpotable Rainwater Catchment Systems
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