Chapter 3 — GENERAL REGULATIONS
316.1 General. Where different sizes of pipes and fittings
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.
are to be connected, the proper size increasers or reducers or reducing fittings shall be used between the two sizes. Copper alloy or cast-iron body cleanouts shall not be used as a
TABLE 313.3 HANGERS AND SUPPORTS
| MATERIALS | TYPES OF JOINTS | HORIZONTAL | VERTICAL | ||
|---|---|---|---|---|---|
| Cast | Lead and Oakum | 5 feet, except 10 feet where 10 foot lengths are installed1, 2, 3 |
5 feet, except 10 feet where 10 foot lengths are installed1, 2, 3 |
5 feet, except 10 feet where 10 foot lengths are installed1, 2, 3 |
Base and each floor, not to exceed 15 feet |
| Cast | Compression Gasket | Every other joint, unless over 4 feet then support each joint1, 2, 3 |
Every other joint, unless over 4 feet then support each joint1, 2, 3 |
Every other joint, unless over 4 feet then support each joint1, 2, 3 |
Base and each floor, not to exceed 15 feet |
| Cast-Iron Hubless | Shielded Coupling | Every other joint, unless over 4 feet then support each joint1,2,3,4 |
Every other joint, unless over 4 feet then support each joint1,2,3,4 |
Every other joint, unless over 4 feet then support each joint1,2,3,4 |
Base and each floor, not to exceed 15 feet |
| Copper & Copper Alloys |
Soldered, Brazed, Threaded, or Mechanical |
11⁄2 inches and smaller, 6 feet; 2 inches and larger, 10 feet |
11⁄2 inches and smaller, 6 feet; 2 inches and larger, 10 feet |
11⁄2 inches and smaller, 6 feet; 2 inches and larger, 10 feet |
Each floor, not to exceed 10 feet5 |
| Steel Pipe for Water or DWV |
Threaded or Welded | 3⁄4 inch and smaller, 10 feet; 1 inch and larger, 12 feet |
3⁄4 inch and smaller, 10 feet; 1 inch and larger, 12 feet |
3⁄4 inch and smaller, 10 feet; 1 inch and larger, 12 feet |
Every other floor, not to exceed 25 feet5 |
| Steel Pipe for Gas | Threaded or Welded | 1⁄2 inch, 6 feet;3⁄4 inch and 1 inch, 8 feet; 11⁄4 inches and larger, 10 feet |
1⁄2 inch, 6 feet;3⁄4 inch and 1 inch, 8 feet; 11⁄4 inches and larger, 10 feet |
1⁄2 inch, 6 feet;3⁄4 inch and 1 inch, 8 feet; 11⁄4 inches and larger, 10 feet |
1⁄2 inch, 6 feet;3⁄4 inch and 1 inch, 8 feet; 11⁄4 inches every floor level |
| Schedule 40 PVC and ABS DWV |
Solvent Cemented | All sizes, 4 feet; allow for expansion every 30 feet3 |
All sizes, 4 feet; allow for expansion every 30 feet3 |
All sizes, 4 feet; allow for expansion every 30 feet3 |
Base and each floor; provide mid-story guides; provide for expansion every 30 feet |
| CPVC | Solvent Cemented | 1 inch and smaller, 3 feet; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 3 feet; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 3 feet; 11⁄4 inches and larger, 4 feet |
Base and each floor; provide mid-story guides |
| CPVC-AL-CPVC | Solvent Cemented | 1⁄2 inch, 5 feet;3⁄4 inch, 65 inches; 1 inch, 6 feet |
1⁄2 inch, 5 feet;3⁄4 inch, 65 inches; 1 inch, 6 feet |
1⁄2 inch, 5 feet;3⁄4 inch, 65 inches; 1 inch, 6 feet |
Base and each floor; provide mid-story guides |
| Lead | Wiped or Burned | Continuous Support | Continuous Support | Continuous Support | Not to exceed 4 feet |
| Steel | Mechanical | In accordance with standards acceptable to the Authority Having Jurisdiction | In accordance with standards acceptable to the Authority Having Jurisdiction | In accordance with standards acceptable to the Authority Having Jurisdiction | In accordance with standards acceptable to the Authority Having Jurisdiction |
| PEX | Cold Expansion, Insert and Compression |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
Base and each floor; provide mid-story guides |
| PEX-AL-PEX | Metal Insert and Metal Compression |
1⁄2 inch 3⁄4 inch 1 inch |
} |
All sizes 98 inches |
Base and each floor; provide mid-story guides |
| PE-AL-PE | Metal Insert and Metal Compression |
1⁄2 inch 3⁄4 inch 1 inch |
} | All sizes 98 inches | Base and each floor; provide mid-story guides |
| PE-RT | Insert and Compression | 1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
Base and each floor; provide mid-story guides |
| Polypropylene (PP) | Fusion weld (socket, butt, sad- dle, electrofusion), threaded (metal threads only), or mechanical |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
1 inch and smaller, 32 inches; 11⁄4 inches and larger, 4 feet |
Base and each floor; provide mid-story guides |
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm Notes: 1 Support adjacent to joint, not to exceed 18 inches (457 mm). 2 Brace not to exceed 40 foot (12 192 mm) intervals to prevent horizontal movement. 3 Support at each horizontal branch connection. 4 Hangers shall not be placed on the coupling. 5 Vertical water lines shall be permitted to be supported in accordance with recognized engineering principles with regard to expansion and contraction, where first approved by the Authority Having Jurisdiction.
54 2022 CALIFORNIA PLUMBING CODE
reducer or adapter from cast-iron drainage pipe to iron pipe size (IPS) pipe.
Get a plain-English answer with a citation back to this text.
Ask AI about this code▸Contents — California Plumbing Code (Title 24, Part 5)
- Chapter 1 — GENERAL CODE PROVISIONS
- Chapter 2 — DEFINITIONS
▸Chapter 3 — GENERAL REGULATIONS
Overview- 301.1 Applicability. This chapter shall govern the general
- 301.2 Minimum Standards. Pipe, pipe fittings, traps, fixtures,…
- 301.3 Alternate Materials and Methods of Construc-
- 301.4 Flood Hazard Areas. Plumbing systems shall be
- 301.5 Alternative Engineered Design. An alternative
- 301.6 One- and Two-Family Dwellings. [HCD 1] The
- 301.7 OSHPD 1R [OSHPD 1R]. For OSHPD 1R, refer to
- 302.1 General. Iron, steel, copper, and copper alloy pipe
- 303.1 General. It shall be unlawful for a person to cause,
- 304.1 General. Plumbing fixtures, drains, appurtenances,
- 305.1 Unlawful Practices. It shall be unlawful for a person to…
- 306.1 Detrimental Wastes. Wastes detrimental to the public sew…
- 306.2 Safe Discharge. Sewage or other waste from a
- 307.1 System. Except as otherwise provided in this code,
- 307.2 Ownership. No subdivision, sale, or transfer of ownershi…
- 308.1 General. Piping, fixtures, or equipment shall not be
- 309.1 Engineering Practices. Design, construction, and
- 309.2 Concealing Imperfections. It is unlawful to conceal crac…
- 309.3 Burred Ends. Burred ends of pipe and tubing shall
- 309.4 Installation Practices. Plumbing systems shall be
- 309.5 Sound Transmission. Plumbing piping systems
- 309.6 Dead Legs. Dead legs shall have a method of flushing.
- 310.1 Fittings. No double hub fitting, single or double tee
- 310.2 Drainage and Vent Piping. No drainage or vent
- 310.3 Waste Connection. No waste connection shall be
- 310.4 Use of Vent and Waste Pipes. Except as hereinafter provi…
- 310.5 Obstruction of Flow. No fitting, fixture and piping
- 310.6 Dissimilar Metals. Except for necessary valves,
- 310.7 Direction of Flow. Valves, pipes, and fittings shall
- 310.8 Screwed Fittings. Screwed fittings shall be ABS,
- 310.9 [OSHPD 1, 2, 3, 4 & 5] Drainage piping over oper-
- 310.10 [OSHPD 1, 3, 4 & 5] Floor drains, waste traps, san-
- 310.11 [SFM] For applications listed in Section 1.11.0 regu-
- 310.12 [OSHPD 1, 2, 4 & 5] Services/Systems and Util-
- 310.13 Telephone and Data Equipment Rooms
- 311.1 General. The drainage system of each new building
- 312.1 General. Piping passing under or through walls shall
- 312.2 Installation. Piping in connection with a plumbing
- 312.3 Building Sewer and Drainage Piping. No building sewer or…
- 312.4 Corrosion, Erosion, and Mechanical Damage.
- 312.5 Protectively Coated Pipe. Protectively coated pipe
- 312.6 Freezing Protection. No water, soil, or waste pipe
- 312.7 Fire-Resistant Construction. Piping penetrations
- 312.8 Waterproofing of Openings. Joints at the roof
- 312.9 Steel Nail Plates. Plastic and copper or copper alloy
- 312.10 Sleeves. Sleeves shall be provided to protect piping th…
- 312.11 Structural Members. A structural member weakened or imp…
- 312.12 Rodentproofing. Strainer plates on drain inlets
- 313.1 General. Piping, fixtures, appliances, and appurtenances…
- 313.2 Material. Hangers and anchors shall be of sufficient
- 313.3 Suspended Piping. Suspended piping shall be supported at…
- 313.4 Alignment. Piping shall be supported in such a manner as…
- 313.5 Underground Installation. Piping in the ground
- 313.6 Hanger Rod Sizes. Hanger rod sizes shall be not
- 313.7 Gas Piping. Gas piping shall be supported by metal
- 313.8 [OSHPD 1, 2, 3, 4 & 5] Refer to Title 24, Part 2 of the
- 314.1 Trenches. Trenches deeper than the footing of a
- 314.2 Tunneling and Driving. Tunneling and driving shall
- 314.3 Open Trenches. Excavations required to be made
- 314.4 Excavations. Excavations shall be completely backfilled …
- 315.1 Unions. Approved unions shall be permitted to be
- 315.2 Prohibited Joints and Connections. A fitting or
- 316.1 General. Where different sizes of pipes and fittings
- 317.1 General. Food or drink shall not be stored, prepared,
- 318.1 General. Tests in accordance with this code, which
- 318.2 Pressure Tests (10 psi or less). Required pressure tests…
- 318.3 Pressure Tests (greater than 10 psi to 100 psi).
- 318.4 Pressure Tests (exceeding 100 psi). Required
- 318.5 Pressure Range. Test gauges shall have a pressure
- 319.1 General. Such piping shall be in accordance with the
- 320.1 General. Where pressure piping systems are rehabilitated…
- Chapter 4 — PLUMBING FIXTURES AND FIXTURE FITTINGS
- Chapter 5 — WATER HEATERS
- Chapter 6 — WATER SUPPLY AND DISTRIBUTION
- Chapter 7 — SANITARY DRAINAGE
- Chapter 8 — INDIRECT WASTES
- Chapter 9 — VENTS
- Chapter 10 — TRAPS AND INTERCEPTORS
- Chapter 11 — STORM DRAINAGE
- Chapter 12 — FUEL GAS PIPING
- Chapter 13 — HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICA…
- Chapter 14 — FIRESTOP PROTECTION
- Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS
- Chapter 16 — NONPOTABLE RAINWATER CATCHMENT SYSTEMS
- Chapter 17 — REFERENCED STANDARDS
- Appendix A — RECOMMENDED RULES FOR SIZING THE WATER SUPPLY SYS…
- Appendix B — EXPLANATORY NOTES ON COMBINATION WASTE AND VENT S…
- Appendix C — ALTERNATE PLUMBING SYSTEMS
- Appendix D — SIZING STORM WATER DRAINAGE SYSTEMS
- Appendix E — MANUFACTURED/MOBILE HOME PARKS AND RECREATIONAL V…
- Appendix F — FIREFIGHTER BREATHING AIR REPLENISHMENT SYSTEMS
- Appendix G — SIZING OF VENTING SYSTEMS
- Appendix H — PRIVATE SEWAGE DISPOSAL SYSTEMS
- Appendix I — INSTALLATION STANDARDS
- Appendix J — COMBINATION OF INDOOR AND OUTDOOR COMBUSTION AND …
- Appendix K — POTABLE RAINWATER CATCHMENT SYSTEMS
- Appendix L — SUSTAINABLE PRACTICES
- Appendix M — PEAK WATER DEMAND CALCULATOR
- Appendix N — IMPACT OF WATER TEMPERATURE ON THE POTENTIAL FOR …