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Earlier editions: 20222019

Chapter 3 — GENERAL REGULATIONS

301.2 Minimum Standards.

California Plumbing Code (Title 24, Part 5) · 2025 edition · updated 2026-09-10 · California

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

Pipe, pipe fittings, traps, fixtures, material, and devices used in a plumbing system shall be listed (third-party certified) by a listing agency (accredited conformity assessment body) as complying with the approved applicable recognized standards referenced in this code, and shall be free from defects. Unless otherwise provided for in this code, materials, fixtures, or devices used or entering into the construction of plumbing systems, or parts thereof shall be submitted to the Authority Having Jurisdiction for approval prior to being installed. 301.2.1 Marking. Each length of pipe and each pipe fitting, trap, fixture, material, and device used in a plumbing system shall have cast, stamped, or indelibly marked on it any markings required by the applicable referenced standards and listing agency, and the manufacturer’s mark or name, which shall readily identify the manufacturer to the end user of the product. Where required by the approved standard that applies, the product shall be marked with the weight and the quality of the product. Materials and devices used or entering into the construction of plumbing and drainage systems, or parts thereof shall be marked and identified in a manner satisfactory to the Authority Having Jurisdiction. Such marking shall be done by the manufacturer. Field markings shall not be acceptable.

Exception: Markings shall not be required on nipples created from cutting and threading of approved pipe.

301.2.2 Standards. Standards listed or referred to in this chapter or other chapters cover materials that will conform to the requirements of this code, where used in accordance with the limitations imposed in this or other chapters thereof and their listing. Where a standard covers materials of various grades, weights, quality, or configurations, the portion of the listed standard that is applicable shall be used. Design and materials for special conditions or materials not provided for herein shall be permitted to be used by special permission of the Authority Having Jurisdiction after the Authority Having Jurisdiction has been satisfied as to their adequacy. A list of plumbing standards that appear in specific sections of this code is referenced in Table 1701.1. Standards referenced in Table 1701.1 shall be applied as indicated in the applicable referenced section. A list of additional approved standards, publications, practices, and guides that are not referenced in specific sections of this code appear in Table 1701.2. An IAPMO Installation Standard is referenced in Appendix I for the convenience of the users of this code. It is not considered as a part of this code unless formally adopted as such by the Authority Having Jurisdiction.

301.2.3 Plastic Pipe, Plastic Pipe Fittings, and Components. Plastic pipe, plastic pipe fittings, and components other than those for gas shall comply with NSF/ANSI 14.

301.2.4 Cast-Iron Soil Pipe, Fittings, and Hubless Couplings. Cast-iron soil pipe, fittings, and hubless couplings shall be third party certified in accordance with ASTM C1277 and CISPI 310 for couplings and ASTM A888, ASTM A74, and CISPI 301 for pipes and fittings. 301.2.5 Existing Buildings. In existing buildings or premises in which plumbing installations are to be altered, repaired, or renovated, the Authority Having Jurisdiction has discretionary powers to permit deviation from the provisions of this code, provided that such proposal to deviate is first submitted for proper determination in order that health and safety requirements, as they pertain to plumbing, shall be observed.

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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
    Overview
    1. 301.1 Applicability. This chapter shall govern the general
    2. 301.2 Minimum Standards. Pipe, pipe fittings, traps, fixtures,…
    3. 301.3 Alternate Materials and Methods of Construction
    4. 301.4 Flood Hazard Areas. Plumbing systems shall be
    5. 301.5 Alternative Engineered Design. An alternative
    6. 301.6 Tall Wood (Mass Timber) Buildings. Plumbing
    7. 301.7 One- and Two-Family Dwellings. [HCD 1] The
    8. 301.8 OSHPD 1R. [OSHPD 1R] For OSHPD 1R, refer to
    9. 302.1 General. Iron, steel, copper, and copper alloy pipe
    10. 303.1 General. It shall be unlawful for a person to cause,
    11. 304.1 General. Plumbing fixtures, drains, appurtenances,
    12. 305.1 Unlawful Practices. It shall be unlawful for a person to…
    13. 306.1 Detrimental Wastes. Wastes detrimental to the public sew…
    14. 306.2 Safe Discharge. Sewage or other waste from a
    15. 307.1 System. Except as otherwise provided in this code,
    16. 307.2 Ownership. No subdivision, sale, or transfer of ownershi…
    17. 308.1 General. Piping, fixtures, appliances, or equipment
    18. 309.1 Engineering Practices. Design, construction, and
    19. 309.2 Concealing Imperfections. It is unlawful to conceal
    20. 309.3 Burred Ends. Burred ends of pipe and tubing shall
    21. 309.4 Installation Practices. Plumbing systems shall be
    22. 309.5 Sound Transmission. Plumbing piping systems
    23. 309.6 Dead Legs. Dead legs shall have a method of flushing.
    24. 310.1 Fittings. No double hub fitting, single or double tee
    25. 310.2 Drainage and Vent Piping. No drainage or vent
    26. 310.3 Waste Connection. No waste connection shall be
    27. 310.4 Use of Vent and Waste Pipes. Except as hereinafter provi…
    28. 310.5 Obstruction of Flow. No fitting, fixture and piping
    29. 310.6 Dissimilar Metals. Except for necessary valves,
    30. 310.7 Direction of Flow. Valves, pipes, and fittings shall
    31. 310.8 Screwed Fittings. Screwed fittings shall be ABS,
    32. 310.9 Female Plastic Connections. Female plastic
    33. 310.10 ABS and PVC Transition Joints. Except as provided in Se…
    34. 310.11 [OSHPD 1, 2, 3, 4 & 5] Drainage piping over oper-
    35. 310.12 [OSHPD 1, 3, 4 & 5] Floor drains, waste traps, san-
    36. 310.13 [SFM] For applications listed in Section 1.11.0 regu-
    37. 310.14 Services/Systems and Utilities. [OSHPD 1, 2, 4
    38. 310.15 Telephone and Data Equipment Rooms.
    39. 311.1 General. The drainage system of each new building
    40. 312.1 General. Piping passing under or through walls shall
    41. 312.2 Installation. Piping in connection with a plumbing
    42. 312.3 Building Sewer and Drainage Piping. No building sewer or…
    43. 312.4 Corrosion, Erosion, and Mechanical Damage.
    44. 312.5 Protectively Coated Pipe. Protectively coated pipe
    45. 312.6 Freezing Protection. No water, soil, or waste pipe
    46. 312.7 Fire-Resistant Construction. Piping penetrations
    47. 312.8 Waterproofing of Openings. Joints at the roof
    48. 312.9 Steel Nail Plates. Plastic piping or tubing, and copper …
    49. 312.10 Sleeves. Sleeves shall be provided to protect piping th…
    50. 312.11 Structural Members. A structural member weakened or imp…
    51. 312.12 Rodentproofing. Strainer plates on drain inlets
    52. 313.1 General. Piping, tubing, fixtures, appliances, and
    53. 313.2 Material. Hangers, supports, and anchors shall be of
    54. 313.3 Suspended Piping. Suspended piping shall be supported at…
    55. 313.4 Alignment. Piping shall be supported in such a manner as…
    56. 313.5 Underground Installation. Piping in the ground
    57. 313.6 Hanger Rod Sizes. Hanger rod sizes shall be not
    58. 313.7 Gas Piping. Gas piping shall be supported by metal
    59. 313.8 [OSHPD 1, 2, 3, 4 & 5] Refer to Title 24, Part 2 of the
    60. 314.1 Trenches. Trenches deeper than the footing of a
    61. 314.2 Tunneling and Driving. Tunneling and driving shall
    62. 314.3 Open Trenches. Excavations required to be made
    63. 314.4 Excavations. Excavations shall be completely backfilled …
    64. 315.1 Unions. Approved unions shall be permitted to be
    65. 315.2 Prohibited Joints and Connections. A fitting or
    66. 316.1 General. Where different sizes of pipes and fittings
    67. 317.1 General. Food or drink shall not be stored, prepared,
    68. 318.1 General. Tests in accordance with this code, which
    69. 318.2 Pressure Tests (10 psi or less). Required pressure tests…
    70. 318.3 Pressure Tests (greater than 10 psi to 100 psi).
    71. 318.4 Pressure Tests (exceeding 100 psi). Required
    72. 318.5 Pressure Range. Test gauges shall have a pressure
    73. 319.1 General. Such piping shall be in accordance with the
    74. 320.1 General. Where pressure piping systems are rehabilitated…
    75. 323.0 Plumbing Equipment Schedules. [OSHPD 1, 2,
  4. Chapter 4 — PLUMBING FIXTURES AND FIXTURE FITTINGS
  5. Chapter 5 — WATER HEATERS
  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 …
  32. Appendix O — NON-SEWERED SANITATION SYSTEMS
  33. Appendix P — PROFESSIONAL QUALIFICATIONS
  34. Appendix Q — INDOOR HORTICULTURAL FACILITIES
  35. Appendix R — TINY HOUSES
  36. Appendix S — ONSITE STORMWATER TREATMENT SYSTEMS

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