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Chapter 5 — WATER HEATERS

509.3 Minimum Safe Performance. Venting systems shall

California Plumbing Code (Title 24, Part 5) · 2022 edition · updated 2026-09-10 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

be designed and constructed to convey all flue and vent gases to the outdoors. [NFPA 54:12.1]

509.3.1 Appliance Draft Requirements. A venting system shall satisfy the draft requirements of the appliance in accordance with the manufacturer’s instructions.

[NFPA 54:12.4.1] 509.3.2 Appliance Venting Requirements. Appliances required to be vented shall be connected to a venting system designed and installed in accordance with the provisions of Section 509.4 through Section 509.15.

[NFPA 54:12.4.2] 509.3.3 Mechanical Draft Systems. Mechanical draft systems shall be listed in accordance with UL 378 and installed in accordance with both the appliance and the mechanical draft system manufacturer’s installation instructions. [NFPA 54:12.4.3.1]

509.3.3.1 Venting. Appliances requiring venting shall be permitted to be vented by means of mechanical draft systems of either forced or induced draft design. [NFPA 54:12.4.3.2]

2022 CALIFORNIA PLUMBING CODE 91

be labeled in accordance with the product standards specified by the appliance manufacturer or shall be listed and labeled in accordance with UL 1738. [NFPA 54:12.5.2] 509.4.2 Plastic Vent Joints. Plastic pipe and fittings used to vent appliances shall be installed in accordance with the appliance manufacturer’s installation instructions. Plastic pipe venting materials listed and labeled in accordance with UL 1738 shall be installed in accordance with the vent manufacturer's installation instructions. Where primer is required, it shall be of a contrasting color. [NFPA 54:12.5.3] 509.4.3 Special Gas Vents. Special gas vents shall be listed and labeled in accordance with UL 1738 and installed in accordance with the special gas vent manufacturer’s installation instructions. [NFPA 54:12.5.4]

TABLE 509.4 TYPE OF VENTING SYSTEM TO BE USED

[NFPA 54: TABLE 12.5.1]

WATER HEATERS

509.3.3.2 Leakage. Forced draft systems and all portions of induced draft systems under positive pressure during operation shall be designed and installed so as to prevent leakage of flue or vent gases into a building. [NFPA 54:12.4.3.3] 509.3.3.3 Vent Connectors. Vent connectors serving appliances vented by natural draft shall not be connected into any portion of mechanical draft systems operating under positive pressure. [NFPA 54:12.4.3.4] 509.3.3.4 Operation. Where a mechanical draft system is employed, provision shall be made to prevent the flow of gas to the main burners when the draft system is not performing so as to satisfy the operating requirements of the appliance for safe performance. [NFPA 54:12.4.3.5] 509.3.3.5 Exit Terminals. The exit terminals of mechanical draft systems shall be not less than 7 feet (2134 mm) above finished ground level where located adjacent to public walkways and shall be located as specified in Section 509.8 and Section 509.8.1 of this code. [NFPA 54:12.4.3.6] 509.3.4 Ventilating Hoods and Exhaust Systems. Where automatically operated appliances, other than commercial cooking appliances, are vented through a ventilating hood or exhaust system equipped with a damper or with a power means of exhaust, provisions shall be made to allow the flow of gas to the main burners only when the damper is open to a position to properly vent the appliance and when the power means of exhaust is in operation. [NFPA 54:12.4.4.1] 509.3.5 Circulating Air Ducts, Above-Ceiling Air- Handling Spaces, and Furnace Plenums. Venting systems shall not extend into or pass through any fabricated air duct or furnace plenum. [NFPA 54:12.4.5.1] 509.3.6 Above-Ceiling or Nonducted Air Han- dling System. Where a venting system passes through an above-ceiling air space or other nonducted portion of an air-handling system, it shall conform to one of the following requirements: (1) The venting system shall be a listed special gas vent,

other system serving a Category III or Category IV appliance, or other positive pressure vent, with joints sealed in accordance with the appliance or vent manufacturer’s instructions. (2) The vent system shall be installed such that no fit tings or joints between sections are installed in the above-ceiling space. (3) The venting system shall be installed in a conduit or

enclosure with joints between the interior of the enclosure and the ceiling space sealed. [NFPA 54:12.4.5.2]

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▸Contents — California Plumbing Code (Title 24, Part 5)
California Plumbing Code (Title 24, Part 5)
  1. Chapter 1 — GENERAL CODE PROVISIONS
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — GENERAL REGULATIONS
  4. Chapter 4 — PLUMBING FIXTURES AND FIXTURE FITTINGS
  5. ▸Chapter 5 — WATER HEATERS
    Overview
    1. 501.1 Applicability. The regulations of this chapter shall
    2. 501.2 California Energy Code Water Heating System
    3. 502.1 General. It shall be unlawful for a person to install,
    4. 503.1 Inspection of Chimneys or Vents. This inspection shall b…
    5. 503.2 Final Water Heater Inspection. This inspection
    6. 504.1 Location. Water heater installations in bedrooms and
    7. 504.2 Vent. Water heaters of other than the direct-vent type
    8. 504.3 Clearance. The clearance requirements for water
    9. 504.4 Pressure-Limiting Devices. A water heater installation s…
    10. 504.5 Temperature-Limiting Devices. A water heater
    11. 504.6 Temperature, Pressure, and Vacuum Relief
    12. 505.1 Water Heaters. Water heaters deriving heat from
    13. 505.2 Safety Devices. Storage-type water heaters and hot
    14. 505.3 Oil-Fired Water Heaters. Oil-fired water heaters
    15. 506.1 General. Air for combustion, ventilation, and dilution of
    16. 506.2 Indoor Combustion Air. The required volume of
    17. 505.4 Indirect-Fired Water Heaters. Indirect-fired water
    18. 506.4 Outdoor Combustion Air. Outdoor combustion air
    19. 506.3 Indoor Opening Size and Location. Openings
    20. 506.5 Combination Indoor and Outdoor Combustion
    21. 506.6 Engineered Installations. Engineered combustion
    22. 506.7 Mechanical Combustion Air Supply. Where all
    23. 506.8 Louvers, Grilles, and Screens. The required size
    24. 506.9 Combustion Air Ducts. Combustion air ducts shall
    25. 507.1 Dielectric Insulator. The Authority Having Jurisdiction …
    26. 507.2 Seismic Provisions. Water heaters shall be anchored
    27. 507.3 Appliance Support. Appliances and equipment shall
    28. 507.4 Ground Support. A water heater supported from the
    29. 507.5 Drainage Pan. Where a water heater is located in an
    30. 507.6 Added or Converted Equipment or Appliances.
    31. 507.7 Types of Gases. The appliance shall be connected to
    32. 507.8 Safety Shutoff Devices for Unlisted LP-Gas
    33. 507.9 Use of Air or Oxygen Under Pressure. Where air
    34. 507.10 Protection of Gas Appliances from Fumes or
    35. 507.11 Process Air. In addition to air needed for combustion i…
    36. 507.12 Flammable Vapors. Appliances shall not be
    37. 507.13 Installation in Residential Garages. Appliances
    38. 507.14 Installation in Commercial Garages. Appliances
    39. 507.15 Installation in Aircraft Hangars. Heaters in aircraft h…
    40. 507.16 Venting of Flue Gases. Appliances shall be vented
    41. 507.17 Extra Device or Attachment. No device or attachment sha…
    42. 507.18 Adequate Capacity of Piping. When additional
    43. 507.19 Avoiding Strain on Gas Piping. Appliances shall
    44. 507.20 Gas Appliance Pressure Regulators. Where the
    45. 507.21 Venting of Gas Appliance Pressure Regula-
    46. 507.22 Bleed Lines for Diaphragm-Type Valves. Bleed
    47. 507.23 Combination of Appliances and Equipment.
    48. 507.24 Installation Instructions. The installing agency
    49. 507.25 Protection of Outdoor Appliances. Appliances
    50. 507.26 Accessibility for Service. All appliances shall be
    51. 507.27 Clearance to Combustible Materials. Appliances and thei…
    52. 508.1 General. Appliances on roofs shall be designed or
    53. 508.2 Installation of Appliances on Roofs. Appliances
    54. 508.3 Appliances on Roofs. Appliances located on roofs or
    55. 508.4 Appliances in Attics and Under-Floor Spaces.
    56. 509.1 Listing. Type B and Type B-W gas vents shall comply
    57. 509.2 Connection to Venting Systems. Except as permitted in Se…
    58. 509.3 Minimum Safe Performance. Venting systems shall
    59. 509.4 Type of Venting System to be Used. The type of
    60. 509.5 Masonry, Metal, and Factory-Built Chimneys.
    61. 509.6 Gas Vents. The installation of gas vents shall meet
    62. 509.7 Single-Wall Metal Pipe. Single-wall metal pipe shall
    63. 509.8 Through-the-Wall Vent Termination. A mechanical draft ve…
    64. 509.9 Condensation Drain. Provision shall be made to
    65. 509.10 Vent Connectors for Category I Appliances.
    66. 509.11 Vent Connectors for Category II, Category III,
    67. 509.12 Draft Hoods and Draft Controls. Vented appliances shall…
    68. 509.13 Manually Operated Dampers. A manually operated damper s…
    69. 509.14 Automatically Operated Vent Dampers. An
    70. 509.15 Obstructions. Devices that retard the flow of vent
    71. 510.1 Single Appliance Vent Table 510.1.2(1) through
    72. 510.2 Multiple Appliance Vent Table 510.2(1) through
  6. Chapter 6 — WATER SUPPLY AND DISTRIBUTION
  7. Chapter 7 — SANITARY DRAINAGE
  8. Chapter 8 — INDIRECT WASTES
  9. Chapter 9 — VENTS
  10. Chapter 10 — TRAPS AND INTERCEPTORS
  11. Chapter 11 — STORM DRAINAGE
  12. Chapter 12 — FUEL GAS PIPING
  13. Chapter 13 — HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICA…
  14. Chapter 14 — FIRESTOP PROTECTION
  15. Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS
  16. Chapter 16 — NONPOTABLE RAINWATER CATCHMENT SYSTEMS
  17. Chapter 17 — REFERENCED STANDARDS
  18. Appendix A — RECOMMENDED RULES FOR SIZING THE WATER SUPPLY SYS…
  19. Appendix B — EXPLANATORY NOTES ON COMBINATION WASTE AND VENT S…
  20. Appendix C — ALTERNATE PLUMBING SYSTEMS
  21. Appendix D — SIZING STORM WATER DRAINAGE SYSTEMS
  22. Appendix E — MANUFACTURED/MOBILE HOME PARKS AND RECREATIONAL V…
  23. Appendix F — FIREFIGHTER BREATHING AIR REPLENISHMENT SYSTEMS
  24. Appendix G — SIZING OF VENTING SYSTEMS
  25. Appendix H — PRIVATE SEWAGE DISPOSAL SYSTEMS
  26. Appendix I — INSTALLATION STANDARDS
  27. Appendix J — COMBINATION OF INDOOR AND OUTDOOR COMBUSTION AND …
  28. Appendix K — POTABLE RAINWATER CATCHMENT SYSTEMS
  29. Appendix L — SUSTAINABLE PRACTICES
  30. Appendix M — PEAK WATER DEMAND CALCULATOR
  31. Appendix N — IMPACT OF WATER TEMPERATURE ON THE POTENTIAL FOR …

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