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Chapter 5 — WATER HEATERS

509.2 Connection to Venting Systems.

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.

Except as permitted in Section 509.2.1 through Section 509.2.7, all appliances shall be connected to venting systems. [NFPA 54:12.3.1]

509.2.1 Appliances Not Required to be Vented. The following appliances shall not be required to be vented: (1) A single listed booster-type (automatic instanta neous) water heater, when designed and used solely for the sanitizing rinse requirements of a dishwashing machine, provided that the appliance is installed with the draft hood in place and unaltered, if a draft hood is required, in a commercial kitchen having a mechanical exhaust system. [Where installed in this manner, the draft hood outlet shall not be less than

WATER HEATERS

36 inches (914 mm) vertically and 6 inches (152 mm) horizontally from any surface other than the appliance.] [NFPA 54:12.3.2(5)] (2) Other appliances listed for unvented use and not pro vided with flue collars. [NFPA 54:12.3.2(10)] 509.2.2 Maximum Input Rating. Where any or all of the appliances in Section 509.2.1(1) and Section 509.2.1(2) are installed so the aggregate input rating exceeds 20 (Btu/h)/ft 3 (207 W/m 3 ) of room or space in which it is installed, one or more shall be provided with venting systems or other approved means for conveying the vent gases to the outdoors so that the aggregate input rating of the remaining unvented appliances does not exceed 20 (Btu/h)/ft 3 (207 W/m 3 ). [NFPA 54:12.3.2.1] 509.2.3 Adjacent Room or Space. Where the calculation includes the volume of an adjacent room or space, the room or space in which the appliances are installed shall be directly connected to the adjacent room or space by a doorway, archway, or other opening of comparable size that cannot be closed. [NFPA 54:12.3.2.2] 509.2.4 Ventilating Hoods. The use of ventilating hoods and exhaust systems to vent appliances shall be limited to industrial appliances and appliances installed in commercial applications. [NFPA 54:12.3.3] 509.2.5 Well-Ventilated Spaces. The flue gases from industrial-type appliances shall not be required to be vented to the outdoors where such gases are discharged into a large and well-ventilated industrial space. [NFPA 54:12.3.4] 509.2.6 Direct-Vent Appliances. Listed direct-vent appliances shall be installed in accordance with the manufacturer’s installation instructions and Section 509.8.2.

[NFPA 54:12.3.5] 509.2.7 Appliances with Integral Vents. Appliances incorporating integral venting means shall be installed in accordance with the manufacturer’s installation instructions, Section 509.8 and Section 509.8.1. [NFPA 54:12.3.6]

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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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