CPC · California Plumbing Code

Fixture connections — inlet fittings and single-vertical drainage conditions

Q: Can I use a double sanitary tee for the two inlets?

The code requires an approved double‑fixture fitting with inlet openings at the same level for a single vertical serving two fixtures (see § 704.2 ). Whether a specific double sanitary tee is an “approved double‑fixture fitting” depends on its construction and listing; confirm with the AHJ and the fitting’s listing.

Q: If my trap‑arm length is just over the limit in Table 1002.2, is there any flexibility?

No — the single‑vertical permission in § 704.2 ties to being “within the distance allowed between a trap and its vent,” which is governed by Table 1002.2. If you exceed the table limit, you cannot rely on the single‑vertical allowance; you must reconfigure or vent differently.

Q: Do the two inlets have to be exactly at the same elevation?

Yes — § 704.2 requires the approved double‑fixture fitting to have inlet openings at the same level . Select a fitting whose inlet geometry meets that requirement and install so the inlets are level.

Q: Where do I find the numeric trap‑to‑vent distances to check compliance?

See Table 1002.2 (referenced in § 1002.2 ) for developed length limits by trap‑arm diameter; use those numbers when evaluating whether two fixtures are within the allowable trap‑to‑vent distance.

For a homeowner: the plumbing code requires that each sink or fixture connect to the drain with a proper, approved inlet fitting. Two adjacent fixtures can share one vertical drain only if the distance from each trap to its vent is short enough and each fixture drains into its own opening in a listed double‑inlet fitting that has both inlets at the same height. Always have the fitting’s listing and the trap‑arm measurements available for your permit/inspector. file

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

Drainage piping must have approved inlet fittings sized and located to match the size and type of fixture to be connected (see § 704.1). Two fixtures placed back‑to‑back or side‑by‑side that are within the permitted trap‑to‑vent distance may be served by a single vertical drainage pipe only when each fixture discharges separately into an approved double‑fixture fitting with inlet openings at the same level (see § 704.2). These rules appear in the Fixture Connections chapter of the CPC.

The single most important practical rule: if you plan to share a vertical stack for two adjacent fixtures, each fixture must waste separately into a listed double‑fixture fitting with both inlets at the same level — and the fixtures must be within the allowable trap‑to‑vent developed length.

Requirements in detail

Inlet fittings (what the code says)

The code requires drainage piping be provided with approved inlet fittings for fixture connections, correctly located according to the size and type of fixture. This is the explicit requirement in § 704.1.

Notes:

The text of § 704.1 states the obligation but does not give prescriptive offsets, offsets from centerline, or exact inlet dimensions — those details come from manufacturer listings and other installation tables and fittings standards (not specified in § 704.1 itself).

Single‑vertical drainage (what the code says)

§ 704.2 permits two fixtures set back‑to‑back or side‑by‑side to be served by a single vertical drainage pipe provided:
- Both fixtures are within the distance allowed between a trap and its vent, and
- Each fixture wastes separately into an approved double‑fixture fitting having inlet openings at the same level.
The phrase distance allowed between a trap and its vent refers to the developed length limits for a trap arm (see Table 1002.2). Table 1002.2 lists the maximum developed lengths (and minimum clearance) by trap‑arm pipe diameter — those dimensional limits govern whether two fixtures are “within the distance allowed” and therefore eligible for the single‑vertical allowance.

Decision‑relevant dimensions / values (quick reference)

Decision item	Key value(s)	Code reference
Requirement for inlet fittings	Approved inlet fittings, located according to size and type of fixture	§ 704.1
Single vertical permitted when	Fixtures are within the trap‑to‑vent distance and each wastes separately into an approved double‑fixture fitting with inlets at same level	§ 704.2
Trap‑to‑vent developed length — 1 1/4" trap arm	Maximum 30 in. (min. trap‑to‑vent 2½ in.)	Table 1002.2 / § 1002.2
Trap‑to‑vent developed length — 1 1/2" trap arm	Maximum 42 in. (min. trap‑to‑vent 3 in.)	Table 1002.2 / § 1002.2
Trap‑to‑vent developed length — 2" trap arm	Maximum 60 in. (min. trap‑to‑vent 4 in.)	Table 1002.2 / § 1002.2
Trap‑to‑vent developed length — 3" trap arm	Maximum 72 in. (min. trap‑to‑vent 6 in.)	Table 1002.2 / § 1002.2
Trap‑to‑vent developed length — 4" trap arm	Maximum 120 in. (min. trap‑to‑vent 8 in.)	Table 1002.2 / § 1002.2

(See Table 1002.2 for full table and notes on slope and special cases.)

What “approved” and “separately wastes” mean here

Approved inlet fitting: the code text of § 704.1 uses the term “approved” but does not list which standards or listings satisfy approval; approval is by the Authority Having Jurisdiction or a referenced standard. The code text itself does not enumerate acceptable product standards in this section.
Wastes separately: the fixtures must discharge into separate inlet openings of the double‑fixture fitting so the discharge from one cannot enter the other inlet, i.e., each has its own inlet at the same level. This is stated by § 704.2.

Exceptions & special cases

The code text for § 704.1 is general (approved fittings, correctly located) and does not include numeric exceptions in that section; specific product exceptions or alternative details are handled elsewhere or by local authority review.
Single vertical drainage allowance is limited by the trap‑arm (trap‑to‑vent developed length) rules in Table 1002.2; if the developed length for a fixture exceeds the table limits, the single‑vertical allowance no longer applies. The CPC text for single‑vertical connections references that distance but does not restate the numeric table in § 704.2 itself. file
If you need a formal determination of whether a specific fitting is “approved” for the intended arrangement, that determination is made by the Authority Having Jurisdiction (AHJ) based on product listings and local interpretations — the controlling sections here do not list specific product standards.

Common mistakes

Assuming any two adjacent fixtures can simply tie into the same vertical stack: the code requires the fixtures be within the permitted trap‑to‑vent developed length and to discharge into an approved double‑fixture fitting with both inlets at the same level — missing either condition is noncompliant. file
Installing a double‑inlet fitting with inlets at different elevations and calling it a “double‑fixture fitting.” § 704.2 expressly requires inlet openings at the same level.
Using an unlisted or non‑“approved” inlet fitting or locating the inlet incorrectly for the fixture type/size — § 704.1 requires approved fittings “correctly located according to the size and type of fixture.” If the fitting isn’t listed/approved, the AHJ can reject it.
Ignoring trap‑arm developed length limits (Table 1002.2) when planning shared verticals — measure the developed length from the trap weir to the inner edge of the vent per § 1002.2 before assuming a single vertical is allowed.

Worked example — concrete scenario

Scenario: Two lavatories (each with a 1½‑inch trap and trap arm) are installed back‑to‑back on a shared wall. Can they be served by one vertical drainage stack using a double‑fixture fitting?

Step 1 — Check trap‑to‑vent developed length:

For a 1½‑inch trap arm, Table 1002.2 gives maximum developed length = 42 inches and minimum trap‑to‑vent clearance = 3 inches. If each lavatory's developed trap arm length to its vent is ≤ 42 in., the length condition is met.

Step 2 — Check the inlet/fitting condition:

§ 704.2 requires that each fixture wastes separately into an approved double‑fixture fitting having inlet openings at the same level. Therefore the installer must use a listed/approved double‑fixture fitting with both inlet openings at the same elevation and connect each lavatory to its own inlet.

Conclusion:

If the trap‑arm developed lengths are ≤ 42 in. and an approved double‑fixture fitting with same‑level inlets is used, the two lavatories may be served by a single vertical drainage pipe under § 704.2. Document the fitting’s approval/listing for the permit inspection. file

Related provisions

§ 704.1 — Inlet fittings (fixture connections) (see above).
§ 704.2 — Single vertical drainage pipe (allows two fixtures on one vertical when conditions are met).
§ 1002.2 / Table 1002.2 — Developed length limits for trap arms (measurement and numeric maxima used to determine eligibility for single vertical).
Table 702.1(1) — Trap and trap arm DFU capacity (useful when sizing traps and checking allowed fixture unit loads).
Table 703.2 — Maximum unit loading and maximum length of drainage and vent piping (useful when you combine fixture loads on stacks).

(If you want, I can produce a one‑page, print‑ready checklist for permit submittal that lists the measurements, the fitting listing info to collect, and the inspection notes you should expect for this arrangement.)

Code references

Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:

CPC § 704.0 High relevance — show source text

704.0 Fixture Connections (Drainage). 704.1 Inlet Fittings. Drainage piping shall be provided with approved inlet fittings for fixture connections, correctly located according to the size and type of fixture proposed to be connected.

704.2 Single Vertical Drainage Pipe. Two fixtures set back-to-back, or side-by-side, within the distance allowed between a trap and its vent, shall be permitted to be served by a single vertical drainage pipe provided that each fixture wastes separately into an approved double-fixture fitting having inlet openings at the same level. 704.3 Commercial Sinks. Pot sinks, scullery sinks, dishwashing sinks, silverware sinks, and other similar fixtures shall be connected directly to the drainage system. A floor drain shall be provided adjacent to the fixture and shall be connected on the sewer side of the sink. No other drainage

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SANITARY DRAINAGE

TABLE 703.2

MAXIMUM UNIT LOADING AND MAXIMUM LENGTH OF DRAINAGE AND VENT PIPING

SIZE OF PIPE (inches)	11⁄4	11⁄2	2	3	4	5	6	8	10	12
Maximum Units Drainage Piping1 Vertical Horizontal	1 1	22, 7 17	163 83	484 354	256 2165	600 4285	1380 7205	3600 26405	5600 46805	8400 82005
Maximum Length Drainage Piping Vertical, (feet) Horizontal (unlimited)	45	65	85	212	300	390	510	750	–	–
Vent Piping Horizontal and Vertical6 Maximum Units Maximum Lengths, (feet)	1 45	83 60	24 120	84 212	256 300	600 390	1380 510	3600 750	–	–

For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm

Notes: 1 Excluding trap arm. 2 Except for sinks, urinals, and dishwashers – exceeding 1 fixture unit. 3 Except for six-unit traps or water closets.

CPC § 0.06 High relevance — show source text

INTERMITTENT FLOW ONLY*

GPM	FIXTURE UNITS
Up to 71⁄2	Equals 1 Fixture Unit
Greater than 71⁄2 to 15	Equals 2 Fixture Units
Greater than 15 to 30	Equals 4 Fixture Units
Greater than 30 to 50	Equals 6 Fixture Units

For SI units: 1 gallon per minute = 0.06 L/s

Discharge capacity exceeding 50 gallons per minute (3.15 L/s) shall be determined by the Authority Having Jurisdiction.

702.3 Continuous Flow. For a continuous flow into a drainage system, such as from a pump, sump ejector, air conditioning equipment, or similar device, 2 fixture units shall be equal to each gallon per minute (gpm) (L/s) of flow.

703.0 Size of Drainage Piping. 703.1 Minimum Size. The minimum sizes of vertical, horizontal, or both drainage piping shall be determined from the total of fixture units connected thereto, and additionally, in the case of vertical drainage pipes, in accordance with their length.

703.2 Maximum Number of Fixture Units. Table 703.2

shows the maximum number of fixture units allowed on a vertical or horizontal drainage pipe, building drain, or building sewer of a given size; the maximum number of fixture units allowed on a branch interval of a given size; and the maximum length (in feet and meters) of a vertical drainage pipe of a given size. 703.3 Sizing per Appendix C. For alternate method of sizing drainage piping, see Appendix C.

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TABLE 703.2

MAXIMUM UNIT LOADING AND MAXIMUM LENGTH OF DRAINAGE AND VENT PIPING

SIZE OF PIPE (inches)	11⁄4	11⁄2	2	3	4	5	6	8	10	12
Maximum Units Drainage Piping1 Vertical Horizontal	1 1	22,

CPC § 702.2 High relevance — show source text
Table 702.2 Discharge Capacity in Gallons Per Minute for

Intermittent Flow Only . . . . . . . . .168

702.3 Continuous Flow . . . . . . . . . . . . . .168

703.0 Size of Drainage Piping . . . . . . . .168

703.1 Minimum Size . . . . . . . . . . . . . . . .168

703.2 Maximum Number of Fixture

Units . . . . . . . . . . . . . . . . . . . . . . .168

703.3 Sizing per Appendix C . . . . . . . . .168

704.0 Fixture Connections (Drainage) . .168

704.1 Inlet Fittings . . . . . . . . . . . . . . . . .168

704.2 Single Vertical Drainage Pipe . . . .168

704.3 Commercial Sinks . . . . . . . . . . . . .168

Table 703.2 Maximum Unit Loading and Maximum Length of Drainage and Vent Piping . . . . . . . . . . . . . .169

705.0 Joints and Connections . . . . . . . .169

705.1 ABS and ABS Co-Extruded

Plastic Pipe and Joints . . . . . . . . .169

705.2 Cast-Iron Pipe and Joints . . . . . . .169

705.3 Copper or Copper Alloy Pipe (DWV) and Joints . . . . . . . . .170

705.4 Galvanized Steel Pipe and Joints . . . . . . . . . . . . . . . . . . .170

705.5 Polyethylene (PE) Sewer Pipe . . .170

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TABLE OF CONTENTS

705.6 PVC and PVC Co-Extruded

Plastic Pipe and Joining Methods . . . . . . . . . . . . . . . . . . . .171

705.7 Stainless Steel Pipe and Joints . . .171

705.8 Vitrified Clay Pipe and Joints . . . .171

705.9 Special Joints . . . . . . . . . . . . . . . .171

705.10 Joints Between

Various Materials . . . . . . . . . . . . .171

706.0 Changes in Direction of Drainage Flow . . . . . . . . . . . . . . .172

706.1 Approved Fittings . . . . . . . . . . . . .172

706.2 Horizontal to Vertical . . . . . . . . . .172

706.3 Horizontal to Horizontal . . . . . . . .172

706.4 Vertical to Horizontal . . . . . . . . . .172

707.0 Cleanouts . . . . . . . . . . . . . . . . . . .172

707.1 Plug . . . . . . . . . . . . . . . . . . . . . . .172

Table 707.1 Cleanouts . . . . . . . . . . . . . . . . . . .172

707.2 Approved . . . . . . . . . . . . . . . . . . .172
CPC § 701.0 High relevance — show source text
701.0 General . . . . . . . . . . . . . . . . . . . . .165

701.1 Applicability . . . . . . . . . . . . . . . . . .165

701.2 Drainage Piping . . . . . . . . . . . . . .165

701.3 Drainage Fittings . . . . . . . . . . . . .165

701.4 Continuous Wastes . . . . . . . . . . .165

701.5 Lead . . . . . . . . . . . . . . . . . . . . . . .165

701.6 Caulking Ferrules . . . . . . . . . . . . .165

701.7 Soldering Bushings . . . . . . . . . . . .165

Table 701.6 Caulking Ferrules . . . . . . . . . . . . .165

Table 701.7 Soldering Bushings . . . . . . . . . . . .165

702.0 Fixture Unit Equivalents . . . . . . . .165

702.1 Trap Size . . . . . . . . . . . . . . . . . . .165

Table 701.2 Materials for Drain, Waste, Vent Pipe and Fittings . . . . . . . . .166

Table 702.1 Drainage Fixture Unit Values (DFU) . . . . . . . . . . . . . . . .167

Table 702.1(1) Maximum Drainage Fixture Units for a Trap and Trap Arm . . .168

702.2 Intermittent Flow . . . . . . . . . . . . . .168

Table 702.2 Discharge Capacity in Gallons Per Minute for

Intermittent Flow Only . . . . . . . . .168

702.3 Continuous Flow . . . . . . . . . . . . . .168

703.0 Size of Drainage Piping . . . . . . . .168

703.1 Minimum Size . . . . . . . . . . . . . . . .168

703.2 Maximum Number of Fixture

Units . . . . . . . . . . . . . . . . . . . . . . .168

703.3 Sizing per Appendix C . . . . . . . . .168

704.0 Fixture Connections (Drainage) . .168

704.1 Inlet Fittings . . . . . . . . . . . . . . . . .168

704.2 Single Vertical Drainage Pipe . . . .168

704.3 Commercial Sinks . . . . . . . . . . . . .168

Table 703.2 Maximum Unit Loading and Maximum Length of Drainage and Vent Piping . . . . . . . . . . . . . .169

705.0 Joints and Connections . . . . . . . .169

705.1 ABS and ABS Co-Extruded

Plastic Pipe and Joints . . . . . . . . .169

705.2 Cast-Iron Pipe and Joints . . . . . . .169

705.3 Copper or Copper Alloy Pipe (DWV) and Joints . . . . . . . . .170

705.4 Galvanized Steel Pipe and Joints . . . . . . . . . . . . . . . . . . .170

705.5 Polyethylene (PE) Sewer Pipe . . .170
CPC § 301.2.1 High relevance — show source text
E 301.2.1 Inlet, System, and Lateral Sizing. Each manufactured home lot drainage inlet shall be assigned a waste loading value of 12 drainage fixture units, and each park drainage system shall be sized in accordance with Table E 301.2(1) or as provided herein. Drainage laterals shall be not less than 3 inches (80 mm) in diameter. E 301.2.2 Engineered Design. A park drainage system that exceeds the fixture unit loading of Table E 301.2(1) or in which the grade and slope of drainage pipe do not meet the minimum specified in Table E 301.2(2) shall be designed by a registered design professional. E 301.2.3 Materials. Pipe and fittings installed underground in manufactured home park drainage systems shall be of a material approved for the purpose. Manufactured home lot drainage inlets and extensions to grade shall be of a material approved for underground use within a building. E 301.3 Lot Drainage Inlet. Provision shall be made for plugging or capping the sewage drain inlet where a manufactured home does not occupy the lot. Surface drainage shall be diverted away from the inlet. The rim of the inlet shall extend to a maximum of 4 inches (102 mm) aboveground elevation. E 301.3.1 Location. Each lot drainage inlet shall be located in the third rear section and within 4 feet (1219 mm) of the proposed location of the manufactured home. E 301.3.2 Materials. Materials used for drainage connections between a manufactured home, and the lot drainage inlet shall be semi-rigid, corrosion resistant, nonabsorbent, and durable. The inner surface shall be smooth.

E 301.4 Drain Connector. A manufactured home shall be connected to the lot drainage inlet using a drain connector consisting of approved pipe not less than Schedule 40, approved fittings and connectors, and not less in size than the manufactured home drainage outlet. An approved cleanout shall be provided between the manufactured home and the lot drainage inlet. The fitting connected to the lot drainage inlet shall be a directional fitting to discharge the flow into the drainage inlet. E 301.4.1 Grade and Gastightness. A drain connector shall be installed or maintained with a grade not less than [1] ⁄ 4 inch per foot (20.8 mm/m). A drain connector shall be gastight and no longer than necessary to make the connection between the manufactured home outlet

and the drain inlet on the lot. A flexible connector shall be permitted to be used at the lot drainage inlet area. Each lot drainage inlet shall be capped gastight where not in use.

E 302.0 Manufactured/Mobile Home Park Water Sup- ply.

E 302.1 Potable Water Supply. An accessible and approved supply of potable water shall be provided in each manufactured home park. Where a public supply of water of approved quantity, quality, and pressure is available at or within the boundary of the park site, the connection shall be made to it and its supply used exclusively. Where an approved public water supply is not available, a private water supply system shall be developed and used as approved by the Authority Having Jurisdiction.
CPC § 1.11.0. Medium relevance — show source text
0||||X|||||||||||||||||||||

This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

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CHAPTER 2

DEFINITIONS

201.0 General.

201.1 Applicability. For the purpose of this code, the following terms have the meanings indicated in this chapter.

No attempt is made to define ordinary words, which are used in accordance with their established dictionary meanings, except where a word has been used loosely, and it is necessary to define its meaning as used in this code to avoid misunderstanding.

202.0 Definition of Terms.

202.1 General. The definitions of terms are arranged alphabetically according to the first word of the term.

203.0 – A –

ABS. Acrylonitrile-butadiene-styrene. Accepted Engineering Practice. That which conforms to technical or scientific-based principles, tests, or standards that are accepted by the engineering profession. Accessible. Where applied to a fixture, connection, appliance, or equipment, “accessible” means having access thereto, but which first may require the removal of an access panel, door, or similar obstruction. Accessible, Readily. Having a direct access without the necessity of removing a panel, door, or similar obstruction. Accessory Dwelling Unit. [HCD 1 & HCD 2] An attached or detached residential dwelling unit that provides complete independent living facilities for one or more per- sons and is located on a lot with a proposed or existing pri- mary residence. Accessory dwelling units shall include permanent provisions for living, sleeping, eating, cooking, and sanitation on the same parcel as the single-family or mul- tifamily dwelling is or will be situated. (See Government Code Section 65852.2.) Air Break. A physical separation which may be a low inlet into the indirect waste receptor from the fixture, appliance, or device indirectly connected. Air Gap, Drainage. The unobstructed vertical distance through the free atmosphere between the lowest opening from a pipe, plumbing fixture, appliance, or appurtenance conveying waste to the flood-level rim of the receptor. Air Gap, Water Distribution. The unobstructed vertical distance through the free atmosphere between the lowest opening from a pipe or faucet conveying potable water to the flood-level rim of a tank, vat, or fixture.

Alternate Water Source. Nonpotable source of water that includes but not limited to gray water, on-site treated nonpotable water, on-site treated nonpotable gray water, rainwater, and reclaimed (recycled) water. Anchors. See Supports. Anodeless Riser. An assembly of steel-cased plastic pipe used to make the transition between plastic piping installed

underground and metallic piping installed aboveground.

[NFPA 54:3.3.3] **Appliance.
CPC § 904.2 Medium relevance — show source text
904.2 Length. Not more than one-third of the total permitted length, in accordance with Table 703.2, of a minimumsized vent shall be installed in a horizontal position. Where a minimum-sized vent is increased one pipe size for its entire length, the maximum length limitation shall not apply.

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VENTS

905.0 Vent Pipe Grades and Connections. 905.1 Grade. Vent and branch vent pipes shall be free from drops or sags, and each such vent shall be level or shall be so graded and connected as to drip back by gravity to the drainage pipe it serves. 905.2 Horizontal Drainage Pipe. Where vents connect to a horizontal drainage pipe, each vent pipe shall have its invert taken off above the drainage centerline of such pipe downstream of the trap being served. 905.3 Vent Pipe Rise. Unless prohibited by structural conditions, each vent shall rise vertically to a point not less than 6 inches (152 mm) above the flood-level rim of the fixture served before offsetting horizontally, and where two or more vent pipes converge, each such vent pipe shall rise to a point not less than 6 inches (152 mm) in height above the floodlevel rim of the plumbing fixture it serves before being connected to any other vent. Vents less than 6 inches (152 mm) above the flood-level rim of the fixture shall be installed with approved drainage fittings, material, and grade to the drain. 905.4 Roof Termination. Vent pipes shall extend undiminished in size above the roof, or shall be reconnected with soil or waste vent of the proper size. 905.5 Location of Opening. The vent pipe opening from soil or waste pipe shall not be below the weir of the trap.

Exception: Water closets and similar fixtures. 905.6 Common Vertical Pipe. Two fixtures shall be permitted to be served by a common vertical pipe where each such fixture wastes separately into an approved double fitting having inlet openings at the same level.

906.0 Vent Termination.

906.1 Roof Termination. Each vent pipe or stack shall extend through its flashing and shall terminate vertically not less than 6 inches (152 mm) above the roof nor less than 1 foot (305 mm) from a vertical surface. ABS and PVC piping exposed to sunlight shall be protected by water based synthetic latex paints.

906.2 Clearance. Each vent shall terminate not less than 10 feet (3048 mm) from, or not less than 3 feet (914 mm) above, an openable window, door, opening, air intake, or vent shaft, or not less than 3 feet (914 mm) in every direction from a lot line, alley and street excepted. 906.2.1 [OSHPD 1,1R, 2, 3, 4 & 5] Each vent pipe shall terminate not less than twenty-five (25) feet (7620 mm) from any air intake or vent shaft. 906.3 Use of Roof. Vent pipes shall be extended separately or combined, of full required size, not less than 6 inches (152 mm) above the roof or firewall. Flagpoling of vents shall be prohibited except where the roof is used for assembly purposes or parking.
CPC § 705.10.2 Medium relevance — show source text
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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. Where connecting stainless steel pipe to other types of piping, listed mechanical joints of the compression type and listed for the specific transition intended shall be used.

706.0 Changes in Direction of Drainage Flow. 706.1 Approved Fittings. Changes in the direction of drainage piping shall be made by the appropriate use of approved fittings and shall be of the angles presented by a one-sixteenth bend, one-eighth bend, or one-sixth bend, or other approved fittings of equivalent sweep. 706.2 Horizontal to Vertical. Horizontal drainage lines, connecting with a vertical stack, shall enter through 45 degree (0.79 rad) wye branches, 60 degree (1.05 rad) wye branches, combination wye and one-eighth bend branches, sanitary tee or sanitary tapped tee branches, or other approved fittings of equivalent sweep. No fitting having more than one inlet at the same level shall be used unless such fitting is constructed so that the discharge from one inlet cannot readily enter any other inlet. Double sanitary tees shall be permitted to be used where the barrel of the fitting is not less than two pipe sizes larger than the largest inlet, (pipe sizes recognized for this purpose are 2 inches, 2 [1] ⁄ 2 inches, 3 inches, 3 [1] ⁄ 2 inches, 4 inches, 4 [1] ⁄ 2 inches, 5 inches, 6 inches, etc.) (50 mm, 65 mm, 80 mm, 90 mm, 100 mm, 115 mm, 125 mm, 150 mm, etc.). 706.3 Horizontal to Horizontal. Horizontal drainage lines connecting with other horizontal drainage lines shall enter through 45 degree (0.79 rad) wye branches, combination wye and one-eighth bend branches, or other approved fittings of equivalent sweep. 706.4 Vertical to Horizontal. Vertical drainage lines connecting with horizontal drainage lines shall enter through 45 degree (0.79 rad) wye branches, combination wye and oneeighth bend branches, or other approved fittings of equivalent sweep. Branches or offsets of 60 degrees (1.05 rad) shall be permitted to be used where installed in a true vertical position.

707.0 Cleanouts.
CPC § 31-2022 Medium relevance — show source text
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"The information contained in this appendix is not part of this American National Standard (ANS) and has not been processed in accordance with ANSI's requirements for an ANS. As such, this appendix may contain material that has not been subjected to public review or a consensus process. In addition, it does not contain requirements necessary for conformance to the standard."

The following IAPMO Installation Standard is included here for the convenience of the users of the Uniform Plumbing Code. It is not considered as a part of the Uniform Plumbing Code unless formally adopted as such. This Installation Standard is an independent, stand-alone document published by the International Association of Plumbing and Mechanical Officials and is printed herein by the expressed written permission of IAPMO.

INSTALLATION STANDARD FOR PEX TUBING SYSTEMS

FOR HOT- AND COLD-WATER DISTRIBUTION

IAPMO IS 31-2022

The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency, or referenced in the adopting ordinance.

1 Scope

1.1 General

1.1.1 This Standard specifies requirements for the installation of SDR 9 CTS crosslinked polyethylene (PEX) tubing and fittings, including cold-expansion, crimp, press, and mechanical compression fittings, intended for hot- and cold-water distribution systems within buildings.

1.1.2 This Standards applies to

(a) SDR 9 CTS PEX tubing complying with ASTM F876 and pressure-rated in accordance with PPI TR-3; and (b) PEX fitting systems complying with (i) ASTM F877, for mechanical compression fittings and metal or plastic insert fittings with stainless steel press sleeves; (ii) ASTM F1807 or ASTM F2159, for metal or plastic insert fittings with copper crimp rings; (iii) ASTM F1960, for cold expansion fittings with PEX reinforced rings; or (iv) ASTM F2080, for cold expansion fittings with metal compression sleeves. 1.2 Terminology

In this Standard,

(a) “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy to comply with the Standard; (b) “should” is used to express a recommendation, but not a requirement; (c) “may” is used to express an option or something permissible within the scope of the Standard; and (d) “can” is used to express a possibility or a capability. Notes accompanying sections of the Standard do not specify requirements or alternative requirements; their purpose is to separate explanatory or informa

tive material from the text. Notes to tables and figures are considered part of the table or figure and can be written as requirements.

1.3 Units of Measurement

SI units are the primary units of record in global commerce. In this Standard, the inch/pound units are shown in parentheses. The values stated in each measurement system are equivalent in application, but each unit system is to be used independently. All references to gallons are to U.S. gallons.

2 Reference Publications
CPC § 110.10 Medium relevance — show source text
Install alternative plumbing piping to permit the discharge from the clothes washer and all showers and bathtubs to be used for an irrigation system in compliance with the California Plumbing Code and any applicable local ordinances; or iv. Install a rainwater catchment system designed to comply with the California Plumbing Code and any applicable local ordinances, and that uses rainwater flowing from at least 65 percent of the available roof area.

B. Multifamily buildings, hotel/motel occupancies and nonresidential buildings. The solar zone shall be located on the roof or overhang of the building or on the roof or overhang of another structure located within 250 feet of the building or on covered parking installed with the building project, and shall have a total area no less than 15 percent of the total roof area of the building excluding any skylight area. The solar zone requirement is applicable to the entire building, including mixed occupancy.

Exception 1 to Section 110.10(b)1B: High-rise multifamily buildings, hotel/motel occupancies, and nonresidential buildings with a permanently installed solar electric system having a nameplate DC power rating, measured under Standard Test Conditions, of no less than one watt per square foot of roof area.

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ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS

Exception 2 to Section 110.10(b)1B: High-rise multifamily buildings, hotel/motel occupancies with a permanently installed domestic solar water-heating system complying with Section 150.1(c)8Biii.

Exception 3 to Section 110.10(b)1B: Buildings with a designated solar zone area that is no less than 50 percent of the potential solar zone area. The potential solar zone area is the total area of any low-sloped roofs where the annual solar access is 70 percent or greater and any steep-sloped roofs oriented between 90 degrees and 300 degrees of true north where the annual solar access is 70 percent or greater. Solar access is the ratio of solar insolation including shade to the solar insolation without shade. Shading from obstructions located on the roof or any other part of the building shall not be included in the determination of annual solar access.

Exception 4 to Section 110.10(b)1B: Low-rise and high-rise multifamily buildings with all thermostats in each dwelling unit are demand response controls that comply with Section 110.12(a), and are capable of receiving and responding to Demand Response Signals prior to granting of an occupancy permit by the enforcing agency. In addition, either A or B below:

A. In each dwelling unit, comply with one of the following measures: i. Install a dishwasher that meets or exceeds the ENERGY STAR Program requirements with either a refrigerator that meets or exceeds the ENERGY STAR Program requirements or a whole house fan driven by an electronically commutated motor; or ii. Install a home automation system that complies with Section 110.12(a) and is capable of, at a minimum, controlling the appliances and lighting of the dwelling and responding to demand response signals; or iii. Install alternative plumbing piping to permit the discharge from the clothes washer and all showers and bathtubs to be used for an irrigation system in compliance with the California Plumbing Code and any applicable local ordinances; or iv.
CPC § 301.2 Medium relevance — show source text
For SI units: 1 inch = 25 mm
- Except for six unit fixtures
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APPENDIX E

TABLE E 301.2(2) MINIMUM GRADE AND SLOPE OF DRAINAGE PIPE

PIPE SIZE SLOPE
(per 100 feet) PIPE SIZE SLOPE
(per 100 feet)

inches inches inches inches

2 25 6 8

3 25 8 4

4 15 10 31⁄2

5 11 12 3

For SI units: 1 inch = 25 mm, 1 inch per foot = 83.3 mm/m

E 301.2.1 Inlet, System, and Lateral Sizing. Each manufactured home lot drainage inlet shall be assigned a waste loading value of 12 drainage fixture units, and each park drainage system shall be sized in accordance with Table E 301.2(1) or as provided herein. Drainage laterals shall be not less than 3 inches (80 mm) in diameter. E 301.2.2 Engineered Design. A park drainage system that exceeds the fixture unit loading of Table E 301.2(1) or in which the grade and slope of drainage pipe do not meet the minimum specified in Table E 301.2(2) shall be designed by a registered design professional. E 301.2.3 Materials. Pipe and fittings installed underground in manufactured home park drainage systems shall be of a material approved for the purpose. Manufactured home lot drainage inlets and extensions to grade shall be of a material approved for underground use within a building. E 301.3 Lot Drainage Inlet. Provision shall be made for plugging or capping the sewage drain inlet where a manufactured home does not occupy the lot. Surface drainage shall be diverted away from the inlet. The rim of the inlet shall extend to a maximum of 4 inches (102 mm) aboveground elevation. E 301.3.1 Location. Each lot drainage inlet shall be located in the third rear section and within 4 feet (1219 mm) of the proposed location of the manufactured home. E 301.3.2 Materials. Materials used for drainage connections between a manufactured home, and the lot drainage inlet shall be semi-rigid, corrosion resistant, nonabsorbent, and durable. The inner surface shall be smooth.
CPC § 811.0. Medium relevance — show source text
defined in Section 811.0.

903.2.3 Marking. Copper or copper alloy tubing, in addition to the required incised marking, shall be marked in accordance with either ASTM B306 or ASTM B88. The colors shall be Type K, green; Type L, blue; Type M, red; and Type DWV, yellow. 903.3 Changes in Direction. Changes in the direction of vent piping shall be made by the appropriate use of approved fittings, and no such pipe shall be strained or bent. Burred ends shall be reamed to the full bore of the pipe.

904.0 Size of Vents.

904.1 Size. The size of vent piping shall be determined from its length and the total number of fixture units connected thereto, in accordance with Table 703.2. The diameter of an individual vent shall be not less than 1 [1] ⁄ 4 inches (32 mm) nor less than one-half the diameter of the drain to which it is connected. In addition, the drainage piping of each building and each connection to a public sewer or a private sewage disposal system shall be vented by means of one or more vent pipes, the aggregate cross-sectional area of which shall be not less than that of the largest required building sewer as determined from Table 703.2. Vent pipes from fixtures located upstream from pumps, ejectors, backwater valves, or other devices that obstruct the free flow of air and other gases between the building sewer and the outside atmosphere shall not be used for meeting the cross-sectional area venting requirements of this section. Exception: Where connected to a common building sewer, the drainage piping of two or more buildings located on the same lot and under one ownership shall be permitted to be vented by means of piping sized in accordance with Table 703.2, provided the aggregate cross-sectional area of vents is not less than that of the largest required common building sewer. 904.2 Length. Not more than one-third of the total permitted length, in accordance with Table 703.2, of a minimumsized vent shall be installed in a horizontal position. Where a minimum-sized vent is increased one pipe size for its entire length, the maximum length limitation shall not apply.

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VENTS

905.0 Vent Pipe Grades and Connections. 905.1 Grade. Vent and branch vent pipes shall be free from drops or sags, and each such vent shall be level or shall be so graded and connected as to drip back by gravity to the drainage pipe it serves. 905.2 Horizontal Drainage Pipe. Where vents connect to a horizontal drainage pipe, each vent pipe shall have its invert taken off above the drainage centerline of such pipe downstream of the trap being served. 905.3 Vent Pipe Rise. Unless prohibited by structural conditions, each vent shall rise vertically to a point not less than 6 inches (152 mm) above the flood-level rim of the fixture served before offsetting horizontally, and where two or more vent pipes converge, each such vent pipe shall rise to a point not less than 6 inches (152 mm) in height above the floodlevel rim of the plumbing fixture it serves before being connected to any other vent. Vents less than 6 inches (152 mm) above the flood-level rim of the fixture shall be installed with approved drainage fittings, material, and grade to the drain.
CPC § 907.2 Medium relevance — show source text
907.2 Yoke Vent. The yoke vent connection to the vent stack shall be placed not less than 42 inches (1067 mm) above the floor level, and the yoke vent connection to the drainage stack shall be using a wye-branch fitting placed below the lowest drainage branch connection serving that floor.

908.0 Wet Venting. 908.1 Vertical Wet Venting. Wet venting is limited to vertical drainage piping receiving the discharge from the trap arm of one and two fixture unit fixtures that also serves as a vent not exceeding four fixtures. Wet-vented fixtures shall be within the same story; provided, further, that fixtures with a continuous vent discharging into a wet vent shall be within the same story as the wet-vented fixtures. No wet vent shall exceed 6 feet (1829 mm) in developed length. 908.1.1 Size. The vertical piping between two consecutive inlet levels shall be considered a wet-vented sec tion. Each wet-vented section shall be not less than one pipe size exceeding the required minimum waste pipe size of the upper fixture or shall be one pipe size exceeding the required minimum pipe size for the sum of the fixture units served by such wet-vented section, whichever is larger, but in no case less than 2 inches (50 mm) in diameter. 908.1.2 Vent Connection. Common vent sizing shall be the sum of the fixture units served but, in no case,

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VENTS

smaller than the minimum vent pipe size required for a fixture served, or by Section 904.0. 908.2 Horizontal Wet Venting for a Bathroom Group. A bathroom group located on the same floor level shall be permitted to be vented by a horizontal wet vent where all of the conditions of Section 908.2.1 through Section 908.2.5 are met.

908.2.1 Vent Connection. The dry vent connection to the wet vent shall be an individual vent for the bidet, shower, or bathtub. One or two vented lavatory(s) shall be permitted to serve as a wet vent for a bathroom group. Only one wet-vented fixture drain or trap arm shall discharge upstream of the dry-vented fixture drain connection. Dry vent connections to the horizontal wet vent shall be in accordance with Section 905.2 and Section

905.3.

908.2.2 Size. The wet vent shall be sized based on the fixture unit discharge into the wet vent. The wet vent shall be not less than 2 inches (50 mm) in diameter for 4 drainage fixture units (dfu) or less, and not less than 3 inches (80 mm) in diameter for 5 dfu or more. The dry vent shall be sized in accordance with Table 702.1 and Table 703.2 based on the total fixture units discharging into the wet vent.

908.2.3 Trap Arm. The length of the trap arm shall not exceed the limits in Table 1002.2. The trap size shall be in accordance with Section 1003.3. The vent pipe opening from the horizontal wet vent, except for water closets and similar fixtures, shall not be below the weir of the trap.
CPC § 25.4 Medium relevance — show source text
For SI units: 1 inch = 25.4 mm

Notes: 1 Maintain 1 ⁄ 4 inch per foot slope (20.8 mm/m). 2 The developed length between the trap of a water closet or similar fixture (measured from the face of the closet flange to the inner edge of the vent) and its vent shall not exceed 6 feet (1829 mm). 3 Horizontally wet vented bathtubs, showers and similar fixtures shall be limited to a maximum of 6 feet (1829 mm) for 1½ inch (40 mm) fixture drains and 8 feet (2438 mm) for 2 inch (50 mm) fixture drains, maintaining ¼ inch per foot slope (20.8 mm/m).

1003.2 Slip Joint Fittings. A maximum of one approved slip joint fitting shall be permitted to be used on the outlet side of a trap, and no tubing trap shall be installed without a listed tubing trap adapter. Listed plastic trap adapters shall be permitted to be used to connect listed metal tubing traps.

1003.3 Size. The size (nominal diameter) of a trap for a given fixture shall be sufficient to drain the fixture rapidly but in no case less than nor more than one pipe size larger than given in Table 702.1. The trap shall be the same size as the trap arm to which it is connected.

TABLE 1002.2

HORIZONTAL LENGTHS OF TRAP ARMS (EXCEPT FOR WATER CLOSETS AND SIMILAR FIXTURES) [1, 2, 3]

For SI units: 1 inch = 25.4 mm

Notes: 1 Maintain 1 ⁄ 4 inch per foot slope (20.8 mm/m). 2 The developed length between the trap of a water closet or similar fixture (measured from the face of the closet flange to the inner edge of the vent) and its vent shall not exceed 6 feet (1829 mm). 3 Horizontally wet vented bathtubs, showers and similar fixtures shall be limited to a maximum of 6 feet (1829 mm) for 1½ inch (40 mm) fixture drains and 8 feet (2438 mm) for 2 inch (50 mm) fixture drains, maintaining ¼ inch per foot slope (20.8 mm/m).

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TRAPS AND INTERCEPTORS

1004.0 Traps.

1004.1 Prohibited. No form of trap that depends for its seal upon the action of movable parts shall be used. No trap that has concealed interior partitions, except those of plastic, glass, or similar corrosion-resisting material, shall be used. “S” traps, bell traps, and crown-vented traps shall be prohibited. No fixture shall be double trapped. Drum and bottle traps shall be installed for special conditions. No trap shall be installed without a vent, except as otherwise provided in this code.

1004.2 Movable Parts. Bladders, check valves or another type of devices with moveable parts shall be prohibited to serve as a trap.

PIPE SIZE	SLOPE (per 100 feet)	PIPE SIZE	SLOPE (per 100 feet)
inches	inches	inches	inches
2	25	6	8
3	25	8	4
4	15	10	31⁄2
5	11	12	3

CPC § 2.2 Medium relevance — show source text

For drainage fixture unit values related to lots within special occupancy parks in all parts of the State of Cal-_ ifornia, see California Code of Regulations, Title 25, Division 1, Chapter 2.2, Article 5, Section 2268.

required, and the unit equivalent of fixtures and devices not shown in Table 702.1 shall be based on the size of trap or trap

arm.

Maximum drainage fixture units for a fixture trap and trap arm loadings for sizes up to 4 inches (100 mm) shall be in accordance with Table 702.1(1).

TABLE 702.1(1) MAXIMUM DRAINAGE FIXTURE UNITS FOR A

TRAP AND TRAP ARM*

SIZE OF TRAP AND TRAP ARM (inches)	DRAINAGE FIXTURE UNIT VALUES (DFU)
11⁄4	1 unit
11⁄2	3 units
2	4 units
3	6 units
4	8 units

For SI Units: 1 inch = 25 mm

*** Exception:** On self-service laundries.

702.2 Intermittent Flow. Drainage fixture units for intermittent flow into the drainage system shall be computed on the rated discharge capacity in gallons per minute (gpm) (L/s) in accordance with Table 702.2.

TABLE 702.1(1) MAXIMUM DRAINAGE FIXTURE UNITS FOR A

TRAP AND TRAP ARM*

For SI Units: 1 inch = 25 mm

*** Exception:** On self-service laundries.

TABLE 702.2

DISCHARGE CAPACITY IN GALLONS PER MINUTE FOR

INTERMITTENT FLOW ONLY*

GPM	FIXTURE UNITS
Up to 71⁄2	Equals 1 Fixture Unit
Greater than 71⁄2 to 15	Equals 2 Fixture Units
Greater than 15 to 30	Equals 4 Fixture Units
Greater than 30 to 50	Equals 6 Fixture Units

For SI units: 1 gallon per minute = 0.06 L/s

Discharge capacity exceeding 50 gallons per minute (3.15 L/s) shall be determined by the Authority Having Jurisdiction.

703.2 Maximum Number of Fixture Units. Table 703.2

CPC § 910.0 Medium relevance — show source text
910.0 Combination Waste and Vent Systems. 910.1 Where Permitted. Combination waste and vent systems shall be permitted where structural conditions preclude the installation of conventional systems as otherwise prescribed by this code. 910.2 Approval. Construction documents for each combination waste and vent system shall first be approved by the Authority Having Jurisdiction before a portion of such system is installed.

910.3 Vents. Each combination waste and vent system, as defined in Chapter 2, shall be provided with a vent or vents adequate to ensure free circulation of air. A branch exceeding 15 feet (4572 mm) in length shall be separately vented in an approved manner. The area of a vent installed in a combination waste and vent system shall be not less than one-half the inside cross-sectional area of the drainpipe served. The vent connection shall be downstream of the uppermost fixture. 910.4 Connections and Size. Branches serving traps shall connect to the main line at an angle not exceeding 2 percent. Each waste pipe and each trap in such a system shall be not less than two pipe sizes exceeding the sizes required by Chapter 7 of this code, and not less than two pipe sizes exceeding a fixture tailpiece or connection. 910.5 Vertical Waste Pipe. No vertical waste pipe shall be used in such a system, except the tailpiece or connection between the outlet of a plumbing fixture and the trap. Such tailpieces or connections shall be as short as possible, and in no case shall exceed 2 feet (610 mm).

Exception: Branch lines shall be permitted to have 45 degree (0.79 rad) vertical offsets.

910.6 Cleanouts. An accessible cleanout shall be installed in each vent for the combination waste and vent system. Cleanouts shall not be required on a wet-vented branch serving a single trap where the fixture tailpiece or connection is not less than 2 inches (50 mm) in diameter and provides ready access for cleaning through the trap.

910.7 Fixtures. No water closet or urinal shall be installed on such a system. Other one, two, or three unit fixtures remotely located from the sanitary system and adjacent to a combination waste and vent system shall be permitted to be connected to such system in the conventional manner by means of waste and vent pipes of regular sizes, providing that the two pipe size increase required in Section 910.4 is based on the total fixture unit load connected to the system.

See Appendix B of this code for explanatory notes on the design of combination waste and vent systems.

911.0 Circuit Venting. 911.1 Circuit Vent Permitted. A maximum of eight flooroutlet water closets, showers, bathtubs, or floor drains con

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VENTS

nected to a horizontal branch shall be permitted to be circuit vented. Each trap arm shall connect horizontally to the horizontal branch being circuit vented in accordance with Table 1002.2. The horizontal branch shall be classified as a drain and a vent from the most downstream trap arm connection to the most upstream trap arm connection to the horizontal branch.

Exception: Back-outlet and wall-hung water closets shall be permitted to be circuit vented provided that no floor-outlet fixtures are connected to the same horizontal branch. Backoutlet and wall-hung water closets shall connect horizontally to the horizontal circuit vented drain.

CPC § 1.6 Medium relevance — show source text

PLUMBING APPLIANCES, APPURTENANCES, OR FIXTURES	MINIMUM SIZE TRAP AND TRAP ARM7 (inches)	PRIVATE	PUBLIC	ASSEMBLY8
Water Closet, greater than 1.6 GPF Gravity Tank6	3	4.0	6.0	8.0
Water Closet, greater than 1.6 GPF Flushometer Valve6	3	4.0	6.0	8.0

For SI units: 1 inch = 25 mm

Notes: 1 Indirect waste receptors shall be sized based on the total drainage capacity of the fixtures that drain thereinto, in accordance with Table 702.2. 2 Provide a 2 inch (50 mm) minimum drain. 3 For refrigerators, coffee urns, water stations, and similar low demands. 4 For commercial sinks, dishwashers, and similar moderate or heavy demands. 5 Buildings having a clothes-washing area with clothes washers in a battery of three or more clothes washers shall be rated at 6 fixture units each for purposes of sizing common horizontal and vertical drainage piping. 6 Water closets shall be computed as 6 fixture units where determining septic tank sizes based on Appendix H of this code. 7 Trap sizes shall not be increased to the point where the fixture discharge is capable of being inadequate to maintain their self-scouring properties. 8 Assembly [Public Use (see Table 422.1)]. 9 For a bathtub to shower retrofit, a 1 1 / 2 inch (40 mm) trap and trap arm shall be permitted with a maximum shower size of 36 inches (914 mm) in width and 60 inches (1524 mm) in length. See Section 408.6 and Section 408.7. 10 For drainage fixture unit values related to lots within mobilehome parks in all parts of the State of California, see California Code of Regulations, Title 25, Division 1, Chapter 2, Article 5, Section 1268. For drainage fixture unit values related to lots within special occupancy parks in all parts of the State of Cal- ifornia, see California Code of Regulations, Title 25, Division 1, Chapter 2.2, Article 5, Section 2268.

required, and the unit equivalent of fixtures and devices not shown in Table 702.1 shall be based on the size of trap or trap

arm.

Maximum drainage fixture units for a fixture trap and trap arm loadings for sizes up to 4 inches (100 mm) shall be in accordance with Table 702.1(1).

TABLE 702.1(1) MAXIMUM DRAINAGE FIXTURE UNITS FOR A

TRAP AND TRAP ARM*

SIZE OF TRAP AND TRAP ARM (inches)	DRAINAGE FIXTURE UNIT VALUES (DFU)
11⁄4	1 unit
11⁄2	3 units
2	4 units
3	6 units
4	8 units

For SI Units: 1 inch = 25 mm

*** Exception:** On self-service laundries.

TABLE 702.1(1) MAXIMUM DRAINAGE FIXTURE UNITS FOR A

TRAP AND TRAP ARM*

CPC § 223.0 Medium relevance — show source text
Trap Arm. Those portions of a fixture drain between a trap and the vent.

Trap Primer. A device and system of piping that maintains a water seal in a remote trap. Trap Seal. The vertical distance between the crown weir and the top dip of the trap. Crown Weir (Trap Weir). The lowest point in the cross-section of the horizontal waterway at the exit of the trap. Top Dip (of the trap). The highest point in the internal cross-section of the trap at the lowest part of the bend (inverted siphon). By contrast, the bottom dip is the lowest point in the internal cross-section. Treated Gray Water. [BSC-CG & HCD 1] Nonpotable water meeting the definition of “gray water” collected and treated on-site suitable for direct beneficial use.

223.0 – U –

UPC. [HCD 1] “UPC” is the latest edition of the Uniform Plumbing Code, published by the International Association of Plumbing and Mechanical Officials. Unsanitary. See Insanitary.

User Outlet. See Station Outlet.

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DEFINITIONS

224.0 – V –

Vacuum. A pressure less than that exerted by the atmosphere.

Vacuum Breaker. See Backflow Preventer.

Vacuum Relief Valve. A device that prevents excessive vacuum in a pressure vessel. Vacuum System-Level 1. A system consisting of central vacuum-producing equipment with pressure and operating controls, shutoff valves, alarm warning systems, gauges, and a network of piping extending to and terminating with suitable station inlets at locations where patient suction could be required. Valve, Balancing. A valve that regulates and controls the return of water to the water heater in a recirculating hot water piping system. Valve, Isolation. A valve that isolates one piece of equipment from another.

Valve, Pressure-Relief. A pressure-actuated valve held closed by a spring or other means and designed automatically to relieve pressure in excess of its setting.

Valve, Riser. A valve at the base of a vertical riser that isolates that riser.

Valve, Service. A valve is serving horizontal piping extending from a riser to a station outlet or inlet. Valve, Source. A single valve at the source that controls a number of units that makes up the source. Valve, Zone. A valve that controls the gas or vacuum to a particular area. Vent. See Plumbing Vent; Dry Vent; Wet Vent. Vent Connector, Gas. That portion of a gas venting system that connects a listed gas appliance beginning at the draft hood or flue collar to a gas vent and is installed entirely within the space or area in which the appliance is located. Vent Offset. An arrangement of two or more fittings and pipe installed for the purpose of locating a vertical section of vent pipe in a different but parallel plane with respect to an adjacent section of vertical vent pipe. [NFPA 54:3.3.101] Vent Pipe. See Plumbing Vent. **Vent Stack.
CPC § 1002.2 Medium relevance — show source text
1002.2 Fixture Traps. Each fixture trap shall have a protecting vent so located that the developed length of the trap arm from the trap weir to the inner edge of the vent shall be within the distance given in Table 1002.2 but in no case less than two times the diameter of the trap arm. 1002.3 Change of Direction. A trap arm shall be permitted to change direction without the use of a cleanout where such change of direction does not exceed 90 degrees (1.57 rad). Horizontal changes in the direction of trap arms shall be in accordance with Section 706.3.

Exception: For trap arms, 3 inches (80 mm) in diameter and larger, the change of direction shall not exceed 135 degrees (2.36 rad) without the use of a cleanout. 1002.4 Vent Pipe Opening. The vent pipe opening from soil or waste pipe, except for water closets and similar fixtures, shall not be below the weir of the trap.

1003.0 Traps – Described. 1003.1 General Requirements. Each trap, except for traps within an interceptor or similar device shall be selfcleaning. Traps for bathtubs, showers, lavatories, sinks, laun

dry sinks, floor drains, urinals, drinking fountains, dental units, and similar fixtures shall be of standard design, weight and shall be of ABS, cast-brass, cast-iron, lead, PP, PVC, or other approved material. An exposed and readily accessible drawn-copper alloy tubing trap, not less than 17 B & S Gauge (0.045 inch) (1.143 mm), shall be permitted to be used on fixtures discharging domestic sewage.

Exception s :

(1) Drawn-copper alloy tubing traps shall not be used for urinals. Each trap shall have the manufacturer’s name stamped legibly in the metal of the trap, and each tubing trap shall have the gauge of the tubing in addition to the manufacturer’s name. A trap shall have a smooth and uniform interior waterway.

(2) [HCD 1 & HCD 2] Non-water supplied urinals conform- ing to ASME A112.19.19-2016, Standard for Vitreous China Nonwater Urinals, or reference standards in Table 1701.1 for non-vitreous ceramic or plastic urinal fixtures.

TABLE 1002.2

HORIZONTAL LENGTHS OF TRAP ARMS (EXCEPT FOR WATER CLOSETS AND SIMILAR FIXTURES) [1, 2, 3]

TRAP ARM PIPE
DIAMETER (inches) DISTANCE TRAP TO
VENT MINIMUM
(inches) LENGTH MAXIMUM
(inches)

11⁄4 21⁄2 30

11⁄2 3 42

2 4 60

3 6 72

4 8 120

Exceeding 4 2 x Diameter 120

For SI units: 1 inch = 25.4 mm
CPC § 904.0. Medium relevance — show source text
VENTS

smaller than the minimum vent pipe size required for a fixture served, or by Section 904.0. 908.2 Horizontal Wet Venting for a Bathroom Group. A bathroom group located on the same floor level shall be permitted to be vented by a horizontal wet vent where all of the conditions of Section 908.2.1 through Section 908.2.5 are met.

908.2.1 Vent Connection. The dry vent connection to the wet vent shall be an individual vent for the bidet, shower, or bathtub. One or two vented lavatory(s) shall be permitted to serve as a wet vent for a bathroom group. Only one wet-vented fixture drain or trap arm shall discharge upstream of the dry-vented fixture drain connection. Dry vent connections to the horizontal wet vent shall be in accordance with Section 905.2 and Section

905.3.

908.2.2 Size. The wet vent shall be sized based on the fixture unit discharge into the wet vent. The wet vent shall be not less than 2 inches (50 mm) in diameter for 4 drainage fixture units (dfu) or less, and not less than 3 inches (80 mm) in diameter for 5 dfu or more. The dry vent shall be sized in accordance with Table 702.1 and Table 703.2 based on the total fixture units discharging into the wet vent.

908.2.3 Trap Arm. The length of the trap arm shall not exceed the limits in Table 1002.2. The trap size shall be in accordance with Section 1003.3. The vent pipe opening from the horizontal wet vent, except for water closets and similar fixtures, shall not be below the weir of the trap.

908.2.4 Water Closet. The water closet fixture drain or trap arm connection to the wet vent shall be downstream of fixture drain or trap arm connections to the horizontal wet vent.

908.2.5 Additional Fixtures. Additional fixtures shall discharge downstream of the wet vent system and be conventionally vented. Only the fixtures within the bathroom group shall connect to the wet-vented horizontal branch.

909.0 Special Venting for Island Fixtures. 909.1 General. Traps for island sinks and similar equipment shall be roughed in above the floor and shall be permitted to be vented by extending the vent as high as possible, but not less than the drainboard height and then returning it downward and connecting it to the horizontal sink drain immediately downstream from the vertical fixture drain. The return vent shall be connected to the horizontal drain through a wyebranch fitting and shall, in addition, be provided with a foot vent taken off the vertical fixture vent by means of a wye branch immediately below the floor and extending to the nearest partition and then through the roof to the open air, or shall be permitted to be connected to other vents at a point not less than 6 inches (152 mm) above the flood-level rim of the fixtures served. Drainage fittings shall be used on the vent below the floor level, and a slope of not less than [1] ⁄ 4 inch per foot (20.8 mm/m) back to the drain shall be maintained. The return bend used under the drainboard shall be a one-piece
CPC § 222.0 Medium relevance — show source text
222.0 – T –

T Rating. The time period that the penetration firestop system, including the penetrating item, limits the maximum temperature rise of 325°F (181°C) above its initial temperature through the penetration on the nonfire side, where tested in accordance with ASTM E814 or UL 1479.

Tailpiece. The pipe or tubing that connects the outlet of a plumbing fixture to a trap. Testing Agency. [HCD 1] See “Approved Testing Agency”. Thermostatic (Temperature Control) Valve. A mixing valve that senses outlet temperature and compensates for fluctuations in incoming hot or cold water temperatures. Toilet. [OSHPD 1, 2, 3, 4 & 5] A fixture within a toilet room which is used for defecation or urination. Toilet Facility. A room or space containing not less than one lavatory and one water closet.

Toilet Room. [OSHPD 1, 2, 3, 4 & 5] A room within or on the premises containing water closets, urinals, and other required facilities. Transition Gas Riser. A listed or approved section or sections of pipe and fittings used to convey fuel gas and installed in a gas piping system to provide a transition from belowground to aboveground.

Trap. A fitting or device so designed and constructed as to provide, where properly vented, a liquid seal that will prevent the back passage of air without materially affecting the flow of sewage or wastewater through it.

Trap Arm. Those portions of a fixture drain between a trap and the vent.

Trap Primer. A device and system of piping that maintains a water seal in a remote trap. Trap Seal. The vertical distance between the crown weir and the top dip of the trap. Crown Weir (Trap Weir). The lowest point in the cross-section of the horizontal waterway at the exit of the trap. Top Dip (of the trap). The highest point in the internal cross-section of the trap at the lowest part of the bend (inverted siphon). By contrast, the bottom dip is the lowest point in the internal cross-section. Treated Gray Water. [BSC-CG & HCD 1] Nonpotable water meeting the definition of “gray water” collected and treated on-site suitable for direct beneficial use.

223.0 – U –

UPC. [HCD 1] “UPC” is the latest edition of the Uniform Plumbing Code, published by the International Association of Plumbing and Mechanical Officials. Unsanitary. See Insanitary.

User Outlet. See Station Outlet.

2025 CALIFORNIA PLUMBING CODE 43

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DEFINITIONS

224.0 – V –

Vacuum. A pressure less than that exerted by the atmosphere.

Vacuum Breaker. See Backflow Preventer.
CPC § 1.11.0. Medium relevance — show source text
1 Exception 2_||||X|X|||||||||||||||||||| |1010.2|||||||||||||||||||X|||||| |1010.3|||||||||||||||||||X|||||| |1010.4|||||||||||||||||||X|||||| |1010.5|||||||||||||||||||X|||||| |1014.1A, B, C||||||||||X|X|X|X|X|X|||||||||| |1015.5||||||||||X|X|X|X|X|X|||||||||| |1015.6||||||||||X|X|X|X|X|X||||||||||

This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

2025 CALIFORNIA PLUMBING CODE 193

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194 2025 CALIFORNIA PLUMBING CODE

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CHAPTER 10

TRAPS AND INTERCEPTORS

1001.0 General.

1001.1 Applicability. This chapter shall govern the materials, design, and installation of traps and interceptors.

1001.2 Where Required. Each plumbing fixture shall be separately trapped by an approved type of liquid seal trap. This section shall not apply to fixtures with integral traps. Not more than one trap shall be permitted on a trap arm. Food waste disposers installed with a set of restaurant, commercial, or industrial sinks shall be connected to a separate trap.

Each domestic clothes washer and each laundry sink shall be connected to a separate and independent trap, except that a trap serving a laundry sink shall also be permitted to receive the waste from a clothes washer set adjacent to it.

The vertical distance between a fixture outlet and the trap weir shall be as short as practicable, but in no case shall the tailpiece exceed 24 inches (610 mm) in length.

One trap shall be permitted to serve a set of not more than three single compartment sinks or laundry sinks of the same depth or three lavatories immediately adjacent to each other and in the same room where the waste outlets are not more than 30 inches (762 mm) apart, and the trap is centrally located where three compartments are installed.

1002.0 Traps Protected by Vent Pipes.

1002.1 Vent Pipes. Each plumbing fixture trap, except as otherwise provided in this code, shall be protected against siphonage, backpressure, and air circulation shall be assured throughout the drainage system using a vent pipe installed in accordance with the requirements of this code.

TRAP ARM PIPE DIAMETER (inches)	DISTANCE TRAP TO VENT MINIMUM (inches)	LENGTH MAXIMUM (inches)
11⁄4	21⁄2	30
11⁄2	3	42
2	4	60
3	6	72
4	8	120
Exceeding 4	2 x Diameter	120

Frequently asked questions

When the code says “approved inlet fittings,” what counts as approved?

Approval is determined by the Authority Having Jurisdiction (AHJ) and product listings/standards; § 704.1 requires an “approved” fitting but does not list the specific product standards in that section. You should bring the fitting’s manufacturer listing or product spec to the AHJ for verification.

Can I use a double sanitary tee for the two inlets?

The code requires an approved double‑fixture fitting with inlet openings at the same level for a single vertical serving two fixtures (see § 704.2). Whether a specific double sanitary tee is an “approved double‑fixture fitting” depends on its construction and listing; confirm with the AHJ and the fitting’s listing.

If my trap‑arm length is just over the limit in Table 1002.2, is there any flexibility?

No — the single‑vertical permission in § 704.2 ties to being “within the distance allowed between a trap and its vent,” which is governed by Table 1002.2. If you exceed the table limit, you cannot rely on the single‑vertical allowance; you must reconfigure or vent differently.

Do the two inlets have to be exactly at the same elevation?

Yes — § 704.2 requires the approved double‑fixture fitting to have inlet openings at the same level. Select a fitting whose inlet geometry meets that requirement and install so the inlets are level.

Where do I find the numeric trap‑to‑vent distances to check compliance?

See Table 1002.2 (referenced in § 1002.2) for developed length limits by trap‑arm diameter; use those numbers when evaluating whether two fixtures are within the allowable trap‑to‑vent distance.

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