Skip to content

Chapter 5 — WATER HEATERS

506.3 Indoor Opening Size and Location. Openings

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.

used to connect indoor spaces shall be sized and located in accordance with the following: (1) Combining spaces on the same story. Each opening shall

have a minimum free area of 1 square inch per 1000 Btu/h (0.002 m 2 /kW) of the total input rating of all appliances in the space but not less than 100 square inches (0.065 m 2 ). One permanent opening shall commence

2022 CALIFORNIA PLUMBING CODE 85

WATER HEATERS

FIGURE 506.4.1(1) ALL COMBUSTION AIR FROM OUTDOORS – INLET AIR FROM VENTILATED CRAWL SPACE AND

OUTLET AIR TO VENTILATED ATTIC

[NFPA 54: FIGURE A.9.3.3.1(1)(a)]

For SI units: 1 foot = 304.8 mm

FIGURE 506.4.1(2) ALL COMBUSTION AIR FROM OUTDOORS

THROUGH VENTILATED ATTIC

[NFPA 54: FIGURE A.9.3.3.1(1)(b)]

FIGURE 506.4.1(3) ALL COMBUSTION AIR FROM OUTDOORS THROUGH HORIZONTAL DUCTS

[NFPA 54: FIGURE A.9.3.3.1(2)]

FIGURE 506.4.2 ALL COMBUSTION AIR FROM OUTDOORS THROUGH

SINGLE COMBUSTION AIR OPENING

[NFPA 54: FIGURE A.9.3.3.2]

86 2022 CALIFORNIA PLUMBING CODE

(2) Where communicating with the outdoors through

horizontal ducts, each opening shall have a minimum free area of 1 square inch per 2000 Btu/h (0.001 m 2 /kW) of total input rating of all appliances in the enclosure. [NFPA 54:9.3.3.1] [See Figure 506.4.1(3)] 506.4.2 One Permanent Opening Method. One permanent opening, commencing within 12 inches (305 mm) of the top of the enclosure, shall be provided. The appliance shall have clearances of at least 1 inch (25.4 mm) from the sides and back and 6 inches (152 mm) from the front of the appliance. The opening shall directly communicate with the outdoors or shall communicate through a vertical or horizontal duct to the outdoors or spaces that freely communicate with the outdoors (see Figure 506.4.2) and shall have a minimum free area of the following:

(1) One square inch per 3000 Btu/h (0.0007 m 2 /kW) of

the total input rating of all appliances located in the enclosure. (2) Not less than the sum of the areas of all vent con nectors in the space. [NFPA 54:9.3.3.2]

Get a plain-English answer with a citation back to this text.

Ask AI about this code
Export this section
▸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 …

GoCodebook provides public access, search, citation, multilingual explanation, and practical interpretation of legally adopted building regulations. It is not a substitute for the official ICC or California code publications.