CPC · California Plumbing Code
When are slip‑joint connections required to be accessible and what access is required?
If a fixture’s slip‑joint is hidden behind finish, the California Plumbing Code requires an access panel or utility space with a least dimension of 12 inches and arranged without obstructions so the joint can be inspected and repaired; if a future fixture is stubbed and the plug is at the trap location, the plumbing for that fixture must be completed in accordance with the CPC (see **§ 402.10** and **§ 402.11**).
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Fixtures that have concealed slip‑joint connections must be provided with an access panel or utility space with a least dimension of 12 inches (305 mm) and arranged so the connection is accessible for inspection and repair — this is the rule in § 402.10.
Where piping is stubbed for a future fixture, the termination must be made with a plugged fitting and, if that plug is located where the trap would be, the plumbing for that future fixture must be complete and comply with the CPC — see § 402.11.
The single most important rule: if a fixture’s slip‑joint is concealed, you must provide an unobstructed access panel or utility space at least 12 inches in its smallest dimension to permit inspection and repair.
Requirements in detail
Scope — when the rule applies
- Applies when a fixture has a concealed slip‑joint connection (i.e., the slip‑joint is not exposed for direct access). § 402.10 is the controlling provision.
- The CPC separately addresses the permissibility of slip joints in fixture drains and traps — slip joints are permitted when listed/approved (see § 705.9.1).
What "accessible" means here
- The code requires either an access panel or a utility space that meets the minimum dimension and is "so arranged without obstructions as to make such connections accessible for inspection and repair." The CPC does not prescribe a precise depth or reach‑angle, only the minimum opening dimension and the requirement that there be no obstructions to access. § 402.10.
Decision table — quick reference
| Decision dimension | Required value / outcome | Code Reference |
|---|---|---|
| Trigger — concealed slip‑joint present? | Access panel or utility space required | § 402.10 |
| Minimum access opening (least dimension) | 12 inches (305 mm) | § 402.10 |
| Arrangement of opening | Must be without obstructions so connections are accessible for inspection & repair | § 402.10 |
| Slip joints permitted in fixture drains/traps? | Yes, where approved/listed | § 705.9.1 |
| Future fixture stump/plug at trap point | Plumbing for that fixture must be complete and comply with the code | § 402.11 |
Practical notes from the text
- The CPC language focuses on the opening size and that it be unobstructed; it does not specify panel type, exact mounting height, or required clearances around the joint beyond "so arranged without obstructions." Use common‑sense service clearance and manufacturer instructions where the code is silent. § 402.10.
- The CPC allows slip joints in fixture drains/traps (so using a slip‑joint is not prohibited) but still requires access when that slip‑joint is concealed. § 705.9.1 and § 402.10.
Exceptions & special cases
- Ground‑joint, flared, or ferrule‑type connections that form a rigid joint are specifically not considered slip joints in CPC language; those are treated differently (see § 705.9.3) — do not confuse them with slip‑joint access requirements.
- The CPC does not create a separate exception for small or concealed utility spaces other than the dimensional and unobstructed requirements given in § 402.10; if the slip‑joint is concealed and the opening does not meet the required dimension/arrangement, the rule is not satisfied.
- For future fixtures: if piping is terminated with a plugged fitting and that plug is at the trap location, the plumbing for that fixture must be complete and in accordance with the CPC — i.e., you cannot leave an incomplete trap assembly at that point. § 402.11.
Common mistakes
- Providing an access panel smaller than 12 inches (305 mm) in the least dimension (e.g., 8" x 8") and assuming that is acceptable — code minimum is 12 in. § 402.10.
- Installing a panel but placing permanent obstructions (shelves, insulation, screw‑fixed blocking) behind it so the slip‑joint cannot be reached — the code requires the opening be "so arranged without obstructions." § 402.10.
- Confusing slip‑joints with ground‑joint / flared / ferrule connections; those latter types are not treated as slip joints and are discussed separately. § 705.9.3 and § 705.9.1.
- Assuming a plugged stub for a future fixture can be left incomplete where the trap would be — if the plug is at the trap point the code requires the plumbing for that fixture be complete. § 402.11.
Worked example — concrete scenario
Scenario: A wall‑hung lavatory will be installed and the manufacturer’s trap assembly uses a slip‑joint. The trap arm and slip‑joint will be concealed inside the finished wall.
- Code requirement: Provide an access panel or utility space with a least dimension of 12 inches (305 mm) and arrange it without obstructions so the slip‑joint can be inspected and repaired. § 402.10.
- Practical implementation: Install a removable access panel that is at least 12 in by 12 in (12" least dimension satisfied) located directly behind and aligned with the trap/slip‑joint so a plumber can reach the nut and trap assembly. Ensure no insulation, blocking, or cabinets block the opening. This satisfies the code minimum; if you prefer extra room for tools, use a larger panel (e.g., 12" × 18"). The CPC does not mandate a second dimension beyond the 12" least dimension nor a specific depth, so document location and size in plans and follow manufacturer instructions where applicable. § 402.10.
If instead the building owner asked for a future lavatory rough‑in and the trap location is plugged: terminate piping with a plugged fitting. If the plug is at the trap location the code requires the plumbing for that fixture be complete and in accordance with the CPC (i.e., you cannot leave required components out where the trap would be). § 402.11.
Related provisions
- § 402.10 — Slip Joint Connections (access requirement).
- § 402.11 — Future Fixtures (plugged fittings/complete system when plug at trap point).
- § 705.9.1 — Slip Joints permitted in fixture drains and traps (approved materials/uses).
- § 705.9.3 — Ground joint / flared / ferrule connections are not considered slip joints.
- § 606.6 — Accessibility requirement for required shutoff/control valves (valves must be accessible) — related accessibility principle for serviceable plumbing components.
- § 403.3 — Protection/insulation of exposed pipes under accessible lavatories (context for accessibility and safety).
Code references
Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:
CPC § 402.10 High relevance — show source text
402.10 Slip Joint Connections. Fixtures having concealed slip joint connections shall be provided with an access panel or utility space not less than 12 inches (305 mm) in its least dimension and so arranged without obstructions as to make such connections accessible for inspection and repair. 402.11 Future Fixtures. Where provisions are made for the future installation of fixtures, those provided for shall be considered in determining the required sizes of the drain and water supply piping. Construction for future installations shall be terminated with a plugged fitting or fittings. Where the plugged
fitting is at the point where the trap of a fixture is installed, the plumbing system for such fixture shall be complete and be in accordance with the plumbing requirements of this code.
403.0 Accessible Plumbing Facilities. 403.1 General. Where accessible facilities are required in applicable building regulations, the facilities shall be installed in accordance with those regulations. [HCD 1-AC] For spe- cific requirements regarding accommodations for persons with disabilities, see Chapter 11A of the California Building Code. 403.2 Fixtures and Fixture Fittings for Persons with Disabilities. Plumbing fixtures and fixture fittings for persons with disabilities shall be in accordance with ICC A117.1 and the applicable standards referenced in Chapter 4. [HCD 1-AC] Specific requirements regarding accommodations for persons with disabilities are contained in Chapter 11A of the California Building Code. 403.3 Exposed Pipes and Surfaces. Water supply and drainpipes under accessible lavatories and sinks shall be insulated or otherwise be configured to protect against contact. Protectors, insulators, or both shall comply with ASME A112.18.9 or ASTM C1822. [HCD 1-AC] Specific requirements regard- ing accommodations for persons with disabilities are contained in Chapter 11A of the California Building Code.
404.0 Waste Fittings and Overflows. 404.1 Waste Fittings. Waste fittings shall comply with ASME A112.18.2/CSA B125.2, ASTM F409 or Table 701.2 for aboveground drainage piping and fittings. 404.2 Overflows. Where a fixture is provided with an overflow, the overflow shall comply with Section 404.2.1 or Section 404.2.2.
404.2.1 Sinks, Lavatories, and Bathtubs. The waste shall be so arranged that the standing water in the fixture shall not rise in the overflow where the stopper is closed or remain in the overflow where the fixture is empty. The overflow pipe from a fixture shall be connected to the house or inlet side of the fixture trap.
404.2.2 Water Closets and Urinals. Overflows on flush tanks shall be permitted to discharge into the water closets or urinals served by them.
405.0 Prohibited Fixtures.
405.1 Prohibited Water Closets. Water closets having an invisible seal or an unventilated space or having walls which are not thoroughly washed at each discharge shall be prohibited. A water closet that might permit siphonage of the contents of the bowl back into the tank shall be prohibited. 405.2 Prohibited Urinals. Trough urinals and urinals with an invisible seal shall be prohibited.
CPC § 402.6.2 High relevance — show source text
Closet rings (closet flanges) shall be adequately designed and secured to support fixtures connected thereto.
402.6.2 Securing Closet Flanges. Closet screws, bolts, washers, and similar fasteners shall be of copper alloy, copper, or other listed equally corrosion-resistant materials. Screws and bolts shall be of a size and number to properly support the fixture installed. 402.6.3 Securing Floor-Mounted, Back-Outlet Water Closet Bowls. Floor-mounted, back-outlet water closet bowls shall be set level with an angle of 90 degrees (1.57 rad) between the floor and wall at the centerline of the fixture outlet. The floor and wall shall have a flat mounting surface not less than 5 inches (127 mm) to the right and left of the fixture outlet centerline. The closet flange shall be secured to the wall mounting surface. Offset, eccentric, or reducing closet flanges shall not be permitted with these fixtures.
The fixture shall be secured to the wall outlet flange or drainage connection and the floor by corrosion-resistant screws or bolts.
402.7 Supply Fittings. The supply lines and fittings for every plumbing fixture shall be so installed as to prevent backflow in accordance with Chapter 6.
402.8 Installation. Fixtures shall be installed in accordance
with the manufacturer’s installation instructions.
402.9 Design and Installation of Plumbing Fixtures. Plumbing fixtures shall be installed in accordance with the manufacturer’s installation instructions. The means of backflow prevention shall not be compromised by the designated fixture fitting mounting surface. 402.10 Slip Joint Connections. Fixtures having concealed slip joint connections shall be provided with an access panel or utility space not less than 12 inches (305 mm) in its least dimension and so arranged without obstructions as to make such connections accessible for inspection and repair. 402.11 Future Fixtures. Where provisions are made for the future installation of fixtures, those provided for shall be considered in determining the required sizes of the drain and water supply piping. Construction for future installations shall be terminated with a plugged fitting or fittings. Where the plugged
fitting is at the point where the trap of a fixture is installed, the plumbing system for such fixture shall be complete and be in accordance with the plumbing requirements of this code.
403.0 Accessible Plumbing Facilities. 403.1 General. Where accessible facilities are required in applicable building regulations, the facilities shall be installed in accordance with those regulations. [HCD 1-AC] For spe- cific requirements regarding accommodations for persons with disabilities, see Chapter 11A of the California Building Code. 403.2 Fixtures and Fixture Fittings for Persons with Disabilities. Plumbing fixtures and fixture fittings for persons with disabilities shall be in accordance with ICC A117.1 and the applicable standards referenced in Chapter 4. [HCD 1-AC] Specific requirements regarding accommodations for persons with disabilities are contained in Chapter 11A of the California Building Code. 403.3 Exposed Pipes and Surfaces. Water supply and drainpipes under accessible lavatories and sinks shall be insulated or otherwise be configured to protect against contact. Protectors, insulators, or both shall comply with ASME A112.18.9 or ASTM C1822.
CPC § 401.2 Medium relevance — show source text
401.2 Quality of Fixtures . . . . . . . . . . . . .59
401.3 Water-Conserving Fixtures and Fittings . . . . . . . . . . . . . . . . . . .59
402.0 Installation . . . . . . . . . . . . . . . . . . .59
402.1 Cleaning . . . . . . . . . . . . . . . . . . . . .59
402.2 Joints . . . . . . . . . . . . . . . . . . . . . . .59
402.3 Securing Fixtures . . . . . . . . . . . . . .59
402.4 Wall-Hung Fixtures . . . . . . . . . . . . .59
402.5 Setting . . . . . . . . . . . . . . . . . . . . . .59
402.6 Flanged Fixture Connections . . . . .59
402.7 Supply Fittings . . . . . . . . . . . . . . . .60
402.8 Installation . . . . . . . . . . . . . . . . . . .60
402.9 Design and Installation of Plumbing Fixtures . . . . . . . . . . . . . .60
402.10 Slip Joint Connections . . . . . . . . . .60
402.11 Future Fixtures . . . . . . . . . . . . . . . .60
403.0 Accessible Plumbing Facilities . . . .60
403.1 General . . . . . . . . . . . . . . . . . . . . . .60
403.2 Fixtures and Fixture Fittings for Persons with Disabilities . . . . . .60
403.3 Exposed Pipes and Surfaces . . . . .60
404.0 Waste Fittings and Overflows . . . . .60
404.1 Waste Fittings . . . . . . . . . . . . . . . . .60
404.2 Overflows . . . . . . . . . . . . . . . . . . . .60
405.0 Prohibited Fixtures . . . . . . . . . . . . .60
405.1 Prohibited Water Closets . . . . . . . .60
405.2 Prohibited Urinals . . . . . . . . . . . . . .60
405.3 Miscellaneous Fixtures . . . . . . . . . .60
406.0 Special Fixtures and Specialties . . .61
406.1 Water and Waste Connections . . . .61
406.2 Special Use Sinks . . . . . . . . . . . . .61
406.3 Special Use Fixtures . . . . . . . . . . .61
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TABLE OF CONTENTS
406.4 Zinc Alloy Components . . . . . . . . .61
407.0 Lavatories . . . . . . . . . . . . . . . . . . . .61
407.1 Application . . . . . . . . . . . . . . . . . . .61
407.2 Water Consumption . . . . . . . . . . . .61
407.3 Limitation of Hot Water
CPC § 1003.3.3.1 Medium relevance — show source text
1003.3.3.1 Horizontal projections for Group I-2 occupancies. Structural elements, fixtures or furnishings shall not project hori- zontally from either side more than 1 [1] / 2 inches (38 mm) into the required width of an exit access corridor serving any area caring for one or more nonambulatory or bedridden persons.
Exceptions: 1. Handrails are permitted to protrude 3 [1] / 2 inches (89 mm) from the wall. 2. Alcohol-based hand-rub dispensers are permitted to protrude 4 inches. 3. Manual fire alarm boxes with a protective cover installed are permitted to protrude 4 inches.
1003.3.4 Clear width. Protruding objects shall not reduce the minimum clear width of accessible routes as required in Chapter 11A or Chapter 11B.
1003.4 Slip-resistant surface. Circulation paths of the means of egress shall have a slip-resistant surface and be securely attached.
1003.5 Elevation change. Where changes in elevation of less than 12 inches (305 mm) exist in the means of egress, sloped surfaces shall be used. Where the slope is greater than one unit vertical in 20 units horizontal (5-percent slope), ramps complying with Section 1012 shall be used. Where the difference in elevation is 6 inches (152 mm) or less, the ramp shall be equipped with either handrails or floor finish materials that contrast with adjacent floor finish materials.
Exceptions:
- Steps at exterior doors complying with Section 1010.1.4.
- A stair with a single riser or with two risers and a tread is permitted at locations not required to be accessible by Chapter 11 A or 11B where the risers and treads comply with Section 1011.5, the minimum depth of the tread is 13 inches (330 mm) and not less than one handrail complying with Section 1014 is provided within 30 inches (762 mm) of the centerline of the normal path of egress travel on the stair.
- A step is permitted in aisles serving seating that has a difference in elevation less than 12 inches (305 mm) at locations not required to be accessible by Chapter 11 A or 11B, provided that the risers and treads comply with Section 1030.14 and the aisle is provided with a handrail complying with Section 1030.16.
Throughout a story in a Group I-2 occupancy, any change in elevation in portions of the means of egress that serve nonambulatory persons shall be by means of a ramp or sloped walkway.
1003.6 Means of egress continuity. The path of egress travel along a means of egress shall not be interrupted by a building element other than a means of egress component as specified in this chapter. Obstructions shall not be placed in the minimum width or required capacity of a means of egress component except projections permitted by this chapter. The minimum width or required capacity of a means of egress system shall not be diminished along the path of egress travel.
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MEANS OF EGRESS
CPC § 606.3 Medium relevance — show source text
Such shutoff valves shall be accessible. A fullway valve shall be installed on the discharge piping from water supply tanks at or near the tank. A fullway valve shall be installed on the cold water supply pipe to each water heater at or near the water heater. 606.3 Multidwelling Units. In multidwelling units, one or more shutoff valves shall be provided in each dwelling unit so that the water supply to a plumbing fixture or group of fixtures in that dwelling unit can be shut off without stopping water supply to fixtures in other dwelling units. These valves shall be accessible in the dwelling unit that they control. 606.4 Multiple Openings. Valves used to control two or more openings shall be fullway gate valves, ball valves, or other approved valves designed and approved for the service intended.
606.5 Control Valve. A control valve shall be installed immediately ahead of each water-supplied appliance and immediately ahead of each slip joint or appliance supply. Parallel water distribution systems shall provide a control valve either immediately ahead of each fixture being supplied or installed at the manifold, and shall be identified with the fixture being supplied. Where parallel water distribution system manifolds are located in attics, crawl spaces, or other locations not readily accessible, a separate shutoff valve shall be required immediately ahead of each individual fixture or appliance served. 606.5.1 Manifolds. Field installed manifolds for water distribution shall conform with the applicable requirements for valves, pipes, and fittings as referenced in this code. Manufactured water distribution manifolds shall
be in accordance with IAPMO IGC 109.
606.6 Accessible. Required shutoff or control valves shall be accessible.
606.7 Multiple Fixtures. A single control valve shall be installed on a water supply line ahead of an automatic metering valve that supplies a battery of fixtures. 606.8 [OSHPD 1, 1R, 2, 3, 4 & 5] Each riser or branch shall be provided with an accessible sectionalizing valve in hot-and cold-water systems to permit servicing or replace- ment of piping or equipment. Stop valves shall be provided at each fixture. 606.9 Check Valve Required. All systems that circulate water by means of a pump or other mechanical device or method shall have a check valve(s) or equal device(s) installed so as to ensure the direction of flow.
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WATER SUPPLY AND DISTRIBUTION
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606.10 Leak Detection Devices. Where leak detection devices for water supply and distribution are installed, they shall comply with ANSI/CAN/IAPMO Z1349.
607.0 Potable Water Supply Tanks. 607.1 General. Potable water supply tanks shall be installed in accordance with the manufacturer’s installation instructions and supported in accordance with the California Building Code . 607.2 Private Well Water Tanks. Pressurized potable water tanks for private well water systems shall comply with ASSE 1099/WSC-PST 2000.
CPC § 12.11.6 Medium relevance — show source text
accordance with the manufacturer’s instructions.
(3) Other approved means. {NFPA 54:12.11.6}
509.10.6 Connector Junctions. Where vent connectors are joined together, the connection shall be made with a manufactured tee or wye fitting. [NFPA 54:12.11.7]
509.10.7 Slope. A vent connector shall be installed without any dips or sags and shall slope upward toward the vent or chimney at least [1] ⁄ 4 inch per foot (20.8 mm/m).
Exception: Vent connectors attached to a mechanical draft system installed in accordance with appliance and the draft system manufacturers’ instructions. [NFPA 54:12.11.8]
509.10.8 Length of Vent Connector. The length of vent connectors shall comply with Section 509.10.8.1 or Section 509.10.8.2.
509.10.8.1 Single Wall Connector. The maximum horizontal length of a single-wall connector shall be 75 percent of the height of the chimney or vent, except for engineered systems. [NFPA 54:12.11.9.1] 509.10.8.2 Type B Double Wall Connector. The maximum horizontal length of a Type B double-wall connector shall be 100 percent of the height of the chimney or vent, except for engineered systems. The maximum length of an individual connector for a chimney or vent system serving multiple appliances, from the appliance outlet to the junction with the common vent or another connector, shall be 100 percent of the height of the chimney or vent.
[NFPA 54:12.11.9.2]
509.10.9 Support. A vent connector shall be supported for the design and weight of the material employed to maintain clearances and prevent physical damage and separation of joints. [NFPA 54:12.11.10]
509.10.10 Chimney Connection. Where entering a flue in a masonry or metal chimney, the vent connector shall be installed above the extreme bottom to avoid stoppage.
Where a thimble or slip joint is used to facilitate removal of the connector, the connector shall be firmly attached to or inserted into the thimble or slip joint to prevent the connector from falling out.
Means shall be employed to prevent the connector from entering so far as to restrict the space between its end and the opposite wall of the chimney flue. [NFPA 54:12.11.11.1 – 12.11.11.3]
509.10.11 Inspection. The entire length of a vent connector shall be readily accessible for inspection, cleaning, and replacement. [NFPA 54:12.11.12]
509.10.12 Fireplaces. A vent connector shall not be connected to a chimney flue serving a fireplace unless the fireplace flue opening is permanently sealed. [NFPA 54:12.11.13]
509.10.13 Passage Through Ceilings, Floors, or Walls. A vent connector shall not pass through a ceiling, floor, or fire-resistance-rated wall. A single-wall metal pipe connector shall not pass through an interior wall.
Exceptions:
(1) Vent connectors made of listed Type B or Type L vent material and serving listed appliances with draft hoods and other appliances listed for use with Type
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CPC § 1.2 Medium relevance — show source text
Calculations_ shall be submitted to OSHPD for review and approval. 11. For in-plane collectors transferring axial loads into the sideplate connection, coordination between sideplate and the regis- tered design professional in responsible charge will be required to confirm the collector connection is sufficient to transfer the load into the moment frame system. This requirement shall be satisfied by designing the sideplate connections in the first bay of a multi-bay sideplate moment frame or an end bay to have a minimum connection capacity, including combined shear (V u + V g ) and moment (M pr ) demands, of at least 1.2 times the M pr at the plastic hinge location when the axial load, as determined by ASCE 7, Section 12.10.2.1 without Ω o , exceeds 0.1 F y A g of the sideplate beam. 12. A complete frame analysis for gravity and design wind loading using LRFD load combinations in Section 1605.1 shall be performed including Demand/Capacity Ratios. Frame beam member nominal moment strengths (M n ) used for gravity and design wind loading for the bolted sideplate connection using Class A or Class B faying surfaces shall be taken as 0.80F y Z for frame beams up to 300 plf and 0.60F y Z for frame beams greater than 300 plf. 13. For moment frame beams with maximum beam shear greater than 90 percent of the vertical bolt shear capacity, a second- ary check is to be provided to confirm the vertical bolt shear capacities are sufficient.
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14. Bolted sideplate connections used on heavy-shallow frame beams for beams greater than 200 plf and shallower than 24 inches (610 mm) in depth shall be considered as an alternative system. 15. Skewed beams shall utilize the link-beam fabrication method with CJP welded splices for skew angles. The skew angle shall be less than 15 degrees. 16. For two-sided bolted sideplate connections sharing the same side plates at the same height and depth across the column, the vertical offset in the beams shall not exceed 10 inches (254 mm).
2202.4.4 Modifications to AISC 358 Chapter 12. The Simpson Strong-Tie (SST) Strong Frame bolted moment connection shall be permitted, provided: 1. Only T-stub yield links are permitted. End plate yield links are not permitted. 2. The biaxial dual-strong axis and column minor axis configurations of the moment connection shall be considered as an alternative system. 3. Beam flange width-to-thickness ratio shall satisfy AISC 341 Table D1.1b. 4. Yield-Link stem-to-beam flange connection bolts shall not slip under wind design demand loads. Yield-Link stem-to-beam flange connection shall be designed to prevent slip using AISC 360 Equation J3-4, where the slip resistance, μ , is taken to be 0.3.
5. Double shear plate connection is permitted to increase connection axial capacity for collector loads. A partial joint penetra- tion (PJP) groove weld for second shear plate is permissible due to space restrictions.
CPC § 318.1 Medium relevance — show source text
318.1 General . . . . . . . . . . . . . . . . . . . . . .54
318.2 Pressure Tests (10 psi or less) . . .54
318.3 Pressure Tests (greater than 10 psi to 100 psi) . . . . . . . . . . . . . .54
318.4 Pressure Tests (exceeding 100 psi) . . . . . . . . . . . . . . . . . . . . . .54
318.5 Pressure Range . . . . . . . . . . . . . . .54
319.0 Medical Gas and Vacuum
Systems . . . . . . . . . . . . . . . . . . . . .54
319.1 General . . . . . . . . . . . . . . . . . . . . . .54
320.0 Rehabilitation of Piping Systems . .54
320.1 General . . . . . . . . . . . . . . . . . . . . . .54
321.0 Essential Plumbing Provisions . . . .54
322.0 Psychiatric Services . . . . . . . . . . . .54
323.0 Plumbing Equipment Schedules . . .55
Table 313.3 Hangers and Supports . . . . . . . . . .55
CHAPTER 4 PLUMBING FIXTURES
AND FIXTURE FITTINGS . . . . . . .57
401.0 General . . . . . . . . . . . . . . . . . . . . . .59
401.1 Applicability . . . . . . . . . . . . . . . . . . .59
401.2 Quality of Fixtures . . . . . . . . . . . . .59
401.3 Water-Conserving Fixtures and Fittings . . . . . . . . . . . . . . . . . . .59
402.0 Installation . . . . . . . . . . . . . . . . . . .59
402.1 Cleaning . . . . . . . . . . . . . . . . . . . . .59
402.2 Joints . . . . . . . . . . . . . . . . . . . . . . .59
402.3 Securing Fixtures . . . . . . . . . . . . . .59
402.4 Wall-Hung Fixtures . . . . . . . . . . . . .59
402.5 Setting . . . . . . . . . . . . . . . . . . . . . .59
402.6 Flanged Fixture Connections . . . . .59
402.7 Supply Fittings . . . . . . . . . . . . . . . .60
402.8 Installation . . . . . . . . . . . . . . . . . . .60
402.9 Design and Installation of Plumbing Fixtures . . . . . . . . . . . . . .60
402.10 Slip Joint Connections . . . . . . . . . .60
402.11 Future Fixtures . . . . . . . . . . . . . . . .60
403.0 Accessible Plumbing Facilities . . . .60
403.1 General . . . . . . . . . . . . . . . . . . . . . .60
CPC § 509.10.10 Medium relevance — show source text
509.10.10 Chimney Connection. Where entering a flue in a masonry or metal chimney, the vent connector shall be installed above the extreme bottom to avoid stoppage.
Where a thimble or slip joint is used to facilitate removal of the connector, the connector shall be firmly attached to or inserted into the thimble or slip joint to prevent the connector from falling out.
Means shall be employed to prevent the connector from entering so far as to restrict the space between its end and the opposite wall of the chimney flue. [NFPA 54:12.11.11.1 – 12.11.11.3]
509.10.11 Inspection. The entire length of a vent connector shall be readily accessible for inspection, cleaning, and replacement. [NFPA 54:12.11.12]
509.10.12 Fireplaces. A vent connector shall not be connected to a chimney flue serving a fireplace unless the fireplace flue opening is permanently sealed. [NFPA 54:12.11.13]
509.10.13 Passage Through Ceilings, Floors, or Walls. A vent connector shall not pass through a ceiling, floor, or fire-resistance-rated wall. A single-wall metal pipe connector shall not pass through an interior wall.
Exceptions:
(1) Vent connectors made of listed Type B or Type L vent material and serving listed appliances with draft hoods and other appliances listed for use with Type
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WATER HEATERS
planes and shall be located so that the relief opening is not obstructed by any part of the appliance or adjacent construction. The appliance and its draft hood shall be located so that the relief opening is accessible for checking vent operation. [NFPA 54:12.13.6]
509.12.6 Clearance. A draft hood shall be located so that its relief opening is not less than 6 inches (152 mm) from any surface except that of the appliance it serves and the venting system to which the draft hood is connected. Where a greater or lesser clearance is indicated on the appliance label, the clearance shall not be less than that specified on the label. Such clearances shall not be reduced. [NFPA 54:12.13.7] 509.13 Manually Operated Dampers. A manually operated damper shall not be placed in any appliance vent connector. Fixed baffles and balancing baffles shall not be classified as manually operated dampers. Balancing baffles shall be mechanically locked in the desired position before placing the appliance in service. Balancing baffles shall be listed in accordance with UL 378. [NFPA 54:12.14.1 – 12.14.3] 509.14 Automatically Operated Vent Dampers. An automatically operated vent damper shall be listed. [NFPA 54:12.15]
509.14.1 Listing. Automatically operated vent dampers for oil fired appliances shall comply with UL 17. The automatic damper control shall comply with UL 378.
509.15 Obstructions. Devices that retard the flow of vent gases shall not be installed in a vent connector, chimney, or vent. The following shall not be considered as obstructions:
CPC § 705.8.1 Medium relevance — show source text
705.8.1 Mechanical Joints. Mechanical joints shall be designed to provide a permanent seal and shall be of the mechanical or push-on joint type. The push-on joint shall include an elastomeric gasket that complies with ASTM C425 and shall provide a compressive force against the spigot and socket after assembly to provide a permanent seal. 705.9 Special Joints. Special joints shall comply with Section 705.9.1 through Section 705.9.4. 705.9.1 Slip Joints. In fixture drains and traps, slip joints of approved materials shall be permitted to be used in accordance with their approvals. 705.9.2 Expansion Joints. Expansion joints shall be accessible, except where in vent piping or drainage stacks, and shall be permitted to be used where necessary to provide for expansion and contraction of the pipes.
705.9.3 Ground Joint, Flared, or Ferrule Con- nections. Copper or copper alloy ground joint flared, or ferrule-type connections that allow adjustment of tubing, but provide a rigid joint where made up, shall not be considered as slip joints.
705.9.4 Transition Joint. A solvent cement transition joint between ABS and PVC building drain and building sewer shall be made using listed transition solvent cement in accordance with ASTM D3138.
[HCD 1 & HCD 2] Plastic pipe and fittings joined with solvent cement shall utilize Low VOC primer(s), if a primer is required, and Low VOC cement(s) as defined in Section 214.0.
705.10 Joints Between Various Materials. Joints
between various materials shall be installed in accordance
with the manufacturer’s installation instructions and with Section 705.10.1 through Section 705.10.4. Mechanical couplings used to join different materials shall comply with ASTM C1173 for belowground use, ASTM C1460 for aboveground use, or ASTM C1461 for aboveground and belowground use. 705.10.1 Copper or Copper Alloy Pipe to Cast- Iron Pipe. Joints from copper or copper alloy pipe or tubing to cast-iron pipe shall be made with a listed compression-type joint or copper alloy ferrule. The copper or copper alloy pipe or tubing shall be soldered or brazed to the ferrule, and the ferrule shall be joined to the castiron hub by a compression or caulked joint.
2025 CALIFORNIA PLUMBING CODE 171
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
SANITARY DRAINAGE
705.10.2 Copper or Copper Alloy Pipe to Threaded Pipe Joints. Joints from copper or copper alloy pipe or tubing to threaded pipe shall be made by the use of a listed copper alloy adapter or dielectric fitting. The joint between the copper or copper alloy pipe and the fitting shall be a soldered or brazed, and the connection between the threaded and the fittings shall be made with a standard pipe size threaded joint. 705.10.3 Plastic Pipe to Other Materials. Where connecting plastic pipe to other types of plastic or other types of piping material; approved listed adapter or transition fittings and listed for the specific transition intended shall be used. Except as provided in Section 705.9.4, PVC and ABS pipe and fittings shall not be solvent welded to any other unlike material. **705.10.4 Stainless Steel Pipe to Other Materials.
CPC § 605.6 Medium relevance — show source text
PE pipe or tubing . . . . . . . . . . . . . . . . . .605.6, 1208.5.4 PE-AL-PE pipe or tubing . . . . . . . . . . . . . . . . . . . .605.7 PE-RT tubing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .605.8
570 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
INDEX
PEX tubing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .605.9 PEX-AL-PEX pipe or tubing . . . . . . . . . . . . . . . . .605.10 Plastic piping, joints, and fittings . . . . .605.2 – 605.3.2.1,
605.6 – 605.12.3,
705.1.1 – 705.1.3,
705.5 – 705.5.1.3,
705.6 – 705.6.3,
705.10.3, 1208.5.10,
1210.1.7.1
PP piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .605.11 Prohibited fittings and practices . . . . . . . . . . . . . . . .310.0, 315.2, 604.2,
1321.8.4, 1321.12.3, 1322.7 PVC piping . . . . . . . . . . . . . . . . .605.12, 705.6, 705.9.4 Screwed joint . . . . . . . . . . . . . . . . . . . . . .310.8, 701.3.1 Slip joint . . . . . . . . . . . . . . . . . . . . . . . . . .221.0, 402.10,
605.14, 705.9.1, 1003.2 Soldered joint . . . . . . . .212.0, 605.1.4, 705.3.3, A 107.3 Solvent cement plastic pipe . . . . . . . . .605.2.2, 605.3.1,
605.12.2, 705.1.2,
705.6.2, 705.9.4 Stainless steel pipe . . . . . . . . . . . . . . .605.13, 605.16.3,
705.7, 705.10.4
Threaded joint . . . . . . . . . . . .605.1.5, 605.2.3, 605.5.2,
605.11.3, 605.12.3, 605.16.1,
705.1.3, 705.3.4, 705.4.2, 705.6.3,
705.10.2, 1208.5.8, 1208.5.9.1,
CPC § 1321.8.4 Medium relevance — show source text
1321.8.4, 1321.12.3, 1322.7 PVC piping . . . . . . . . . . . . . . . . .605.12, 705.6, 705.9.4 Screwed joint . . . . . . . . . . . . . . . . . . . . . .310.8, 701.3.1 Slip joint . . . . . . . . . . . . . . . . . . . . . . . . . .221.0, 402.10,
605.14, 705.9.1, 1003.2 Soldered joint . . . . . . . .212.0, 605.1.4, 705.3.3, A 107.3 Solvent cement plastic pipe . . . . . . . . .605.2.2, 605.3.1,
605.12.2, 705.1.2,
705.6.2, 705.9.4 Stainless steel pipe . . . . . . . . . . . . . . .605.13, 605.16.3,
705.7, 705.10.4
Threaded joint . . . . . . . . . . . .605.1.5, 605.2.3, 605.5.2,
605.11.3, 605.12.3, 605.16.1,
705.1.3, 705.3.4, 705.4.2, 705.6.3,
705.10.2, 1208.5.8, 1208.5.9.1,
1208.5.9.5, 1322.5, A 107.3
Tightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105.3 Transition joint . . . . . . . . . . . . . . . . . . . . . . . . . .705.9.4 Various materials . . . . . . . . .605.16, 705.10, 1210.1.3.8
Vitrified clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .705.8 Welded joint . . . . . . . . . . . . . .212.0, 605.13.2, 705.7.2, 1208.5.9.1, 1322.1, F 1101.2
– L –
LABELED . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.0, 301.2
LAUNDRY SINKS . . . . . . . . . . . . . . . . . . . . . . . . . . . .1001.2
LAVATORIES . . . . . . . . . . . . . . . .407.0, 422.9, Table 702.1,
1503.8.2.1, E 501.4
LAVATORIES IN SETS . . . . . . . . . . . . . .214.0, Table 702.1
LAVATORY
Frequently asked questions
Do I always need an access panel if the trap nut is behind a finished wall?
Yes — if the slip‑joint connection is concealed, § 402.10 requires an access panel or utility space meeting the 12‑inch least dimension and arranged without obstructions so the connection is accessible.
Is a 12" × 8" panel acceptable because one dimension is 12"?
No — the code requires 12 inches (305 mm) in its least dimension. That means the smallest side must be at least 12". A 12" × 8" panel does not meet the requirement because the least dimension is 8". § 402.10.
If I use a ground‑joint or flared connection, do I still need an access panel?
Ground‑joint, flared, or ferrule‑type connections are not considered slip joints under the CPC, per § 705.9.3; however, accessibility for inspection/repair of any concealed serviceable connection is still governed by applicable installation requirements (and best practice is to provide access).
Can I leave a stubbed/plugged fitting for a future fixture without finishing the trap?
You can terminate with a plugged fitting, but § 402.11 says if the plug is at the point where the trap would be installed, the plumbing system for that future fixture shall be complete and in accordance with the plumbing requirements of this code.
Are there CPC requirements for the type of access panel (material, latch, fire rating)?
§ 402.10 specifies minimum size and unobstructed arrangement only; it does not prescribe material, latch type, or fire rating. Use a panel appropriate to the construction, manufacturer instructions, and any other applicable code requirements (e.g., fire assembly continuity). § 402.10.
More in California Plumbing Code
- Administration
- Definitions
- General Regulations
- Plumbing Fixtures and Fixture Fittings
- Water Heaters
- Water Supply and Distribution
- Sanitary Drainage (Drain, Waste, and Vent)
- Indirect Wastes
- Vents
- Traps and Interceptors
- Storm Drainage
- Fuel Gas Piping
- Health Care Facilities — Medical Gas and Medical Vacuum Systems
- Alternate Water Sources and Nonpotable Rainwater Catchment Systems
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