CPC · California Plumbing Code

Roof termination heights and clearances from openings and intakes

Q: Do vents always need to be 6 inches above the roof?

Yes — § 906.1 requires each vent pipe or stack to terminate not less than 6 inches (152 mm) above the roof. That is the baseline vertical requirement; additional clearance rules to openings or intakes may force a higher termination.

Q: If a vent is 12 feet from an intake, does it need to be 3 feet higher?

No — if the vent is at least 10 feet horizontally from the intake, the 10 ft horizontal rule is satisfied and the 3 ft vertical above‑opening option is not required. § 906.2 provides the alternatives.

Q: How does the 25‑foot OSHPD rule work?

For the OSHPD facility classes listed in the code, § 906.2.1 requires that each vent pipe terminate not less than 25 ft (7620 mm) from any air intake or vent shaft. This is a separate, more stringent requirement for those facility types.

Q: Are lot lines treated the same as streets and alleys?

No — § 906.2 requires a vent termination to be not less than 3 ft in every direction from a lot line, but the text explicitly excepts alley and street locations from that lot‑line limitation.

Your plumbing vents must extend through the roof flashing and be at least 6 inches above the roof and 1 foot from any vertical surface. Additionally each vent must be either 10 feet away from, or 3 feet higher than, any openable window, door, air intake, or vent shaft — and in certain OSHPD healthcare facilities the vent must be 25 feet from intakes. These numeric clearances come directly from **§ 906.1**, **§ 906.2**, and **§ 906.2.1** of the California Plumbing Code.

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Last reviewed: July 6, 2026

What the code requires — plain English

Vents and stacks must extend through their flashings and terminate at least 6 inches above the roof and 1 foot from a vertical surface per § 906.1. Each vent termination must also be either at least 10 feet away from, or at least 3 feet above, any openable window, door, opening, air intake, or vent shaft (and 3 feet from lot lines) per § 906.2. For hospitals/OSHPD facilities a larger separation applies: a vent must be at least 25 feet from any air intake or vent shaft per § 906.2.1.

The single most important rule: place vent terminations at least 6 in above the roof and keep them either 10 ft away from or 3 ft higher than any operable opening or air intake (or 25 ft from intakes at certain OSHPD facilities).

Requirements in detail

Key defined terms (first mention bolded)

Vent — the pipe that carries sewer/gas venting to the outdoors.
Roof termination / termination — the point where the vent exits above the roof flashing.
Air intake — an opening that brings outdoor air to HVAC or mechanical systems.
Openable window / opening — any window or opening that can be opened to the outdoors.

Mandatory minimums (summary table)

Dimension / Requirement	Value	When it applies	Code Reference
Minimum vertical above roof	6 in (152 mm)	Every vent pipe or stack must extend through flashing and terminate at least this high above roof	§ 906.1
Minimum horizontal distance from a vertical surface	1 ft (305 mm)	Applies to vent termination location from vertical surfaces	§ 906.1
Separation from openable window/door/opening/air intake/vent shaft	10 ft (3048 mm) horizontally OR 3 ft (914 mm) vertically above the opening	Vent must meet at least one of these (whichever is achieved)	§ 906.2
Minimum distance from lot line (in every direction)	3 ft (914 mm)	Applies except where alley and street are excepted	§ 906.2
OSHPD / certain health-care facilities	25 ft (7620 mm) from any air intake or vent shaft	Applies to the listed OSHPD facility classes	§ 906.2.1
Protection of ABS/PVC exposed to sunlight	Painting with water‑based synthetic latex paint required	Applies when ABS/PVC piping is exposed to sunlight at the termination	§ 906.1

Notes:

The code gives alternatives for separation: being 10 ft horizontally away OR 3 ft vertically higher than the opening are alternative compliance methods for each opening/intake. § 906.2 clarifies the “or” condition.
Lot line clearance is stated as 3 ft in every direction, but alleys and streets are excepted (they do not require that 3 ft separation per the text of § 906.2).

Practical placement rules (short bullets)

The vent must pass through the roof flashing and terminate vertically (not slanted) at the required height. § 906.1.
If an intake is close (<10 ft) to a vent, raise the vent so it is at least 3 ft above the intake opening, or relocate the vent to be ≥10 ft away. § 906.2.
For OSHPD (hospital) projects check § 906.2.1 — the stricter 25 ft separation to any air intake or vent shaft applies.

Exceptions & special cases

OSHPD facilities (the code text labels specific OSHPD classes) require 25 ft separation from any air intake or vent shaft — this supersedes the 10 ft / 3 ft rule for those facilities. § 906.2.1.
The lot line separation excludes alley and street locations — the text of § 906.2 excludes alley and street from the lot‑line limitation.
ABS and PVC exposed to sunlight at the roof termination must be protected with a water‑based synthetic latex paint (per § 906.1). If you are using materials subject to UV degradation, comply with that protection requirement.
The code provides other related termination provisions for gas vents and appliance vents (see Related provisions below) — these can impose additional vertical heights or clearance rules for specific vent types; consult those sections when gas appliances are involved.

If a detail you need (for example, a definition for a particular term like “openable window” or an exception by appliance type) is not within § 906.1–906.2.1, check the related sections cited below because the CPC distributes venting rules across Chapter 9 and appliance venting chapters. The retrieved text for the controlling sections covers the numeric clearances above; it does not, for example, redefine “openable” beyond common meaning.

Common mistakes

Treating the 3 ft and 10 ft requirements as cumulative rather than alternatives — the vent needs to meet either the horizontal 10 ft separation or the vertical 3 ft separation to that opening, not both, unless other sections require more. § 906.2.
Forgetting the 1 ft clear distance from a vertical surface when counting roof‑edge, parapet, or wall proximity to the termination (§ 906.1).
Overlooking the 3 ft lot‑line clearance (in every direction) for vents adjacent to property lines (unless adjacent to an alley/street, which the section excepts). § 906.2.
Not applying the 25 ft OSHPD rule where it applies. Designers sometimes miss that health‑care projects are in the special‑case bracket in § 906.2.1.
Failing to protect PVC/ABS exposed to sunlight at the termination as required by § 906.1.

Worked example

Scenario:

A roof‑mounted plumbing vent terminates 18 inches (1.5 ft) above an adjacent roof surface.
An HVAC outside air intake opening sits on the adjacent roof and its opening lip is at roof level. The horizontal distance between the vent termination and the intake opening is 8 ft (less than 10 ft). The project is a non‑OSHPD residential building.

Code check:

Because the vent is within 10 ft horizontally of the intake (8 ft), the vent must be at least 3 ft (36 in) above the intake opening per § 906.2. Currently the vent is 18 in above the intake. § 906.2.
Therefore you must increase the vent termination height by at least 18 in (36 in required − 18 in existing) so the termination becomes at least 3 ft above the intake. Also ensure the final termination remains at least 6 in above the roof and 1 ft from any vertical surface per § 906.1.

If this were an OSHPD hospital intake, the required separation would instead be 25 ft, so a different approach (relocation or different routing) would be necessary. § 906.2.1.

Related provisions (check these when designing or reviewing)

§ 905.4 Roof Termination — additional roof termination context in the vent‑grade/venting chapter.
§ 905.3 Vent Pipe Rise — vent rise requirements before offsets (may affect where the termination can be located).
§ 509.6 Gas Vents — special termination heights and offsets for gas vents and listed caps (applies when the vent is a gas appliance vent).
§ 906.3 Use of Roof — rules about flag‑poling and extending vents when the roof is used for assembly or parking.

(These related sections appear elsewhere in Chapter 9 and the appliance venting sections; consult them for appliance‑specific or roof‑use special rules.)

Code references

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

CPC § 904.2 High 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.

2025 CALIFORNIA PLUMBING CODE 189

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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 § 510.3 High relevance — show source text
118 2025 CALIFORNIA MECHANICAL CODE

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EXHAUST SYSTEMS

on the top portion of the grease duct in accordance with Section 510.3 and shall be labeled at the interior portion of the duct.

510.9 Termination of Type I Hood Exhaust System. The exhaust system shall terminate as follows:

(1) Outside the building with a fan or duct.

(2) Through the roof or to the roof from outside, as in Section 510.9.1, or through a wall, as in Section 510.9.2. [NFPA 96:7.8.1] 510.9.1 Rooftop Terminations. Rooftop terminations shall be arranged with or provided with the following:

(1) A minimum of 10 feet (3048 mm) of horizontal clearance from the outlet to adjacent buildings, property lines, and air intakes.

(2) A minimum of 5 feet (1524 mm) of horizontal clearance from the outlet (fan housing) to any combustible structure.

(3) A vertical separation of 3 feet (914 mm) above any air intakes within 10 feet (3048 mm) of the exhaust outlet.

(4) The ability to drain grease out of any traps or low points formed in the fan or duct near the termination of the system into a collection container that is noncombustible, closed, rainproof, and structurally sound for the service to which it is applied and that will not sustain combustion.

(5) A grease collection device that is applied to exhaust systems that does not inhibit the performance of any fan.

(6) Grease collection systems that meet the requirements of Section 510.9.1(4) and Section 510.9.1(5).

(7) A listed grease duct complying with Section 507.4.7 or ductwork complying with Section 507.4.8.

(8) A hinged upblast fan supplied with flexible weatherproof electrical cable and service hold-open retainer to permit inspection and cleaning that is listed for commercial cooking equipment with the following conditions:

(a) Where the fan attaches to the ductwork, the ductwork is a minimum of 18 inches (457 mm) away from any roof surface, as shown in Figure 510.9.1.

(b) The fan discharges a minimum of 40 inches (1016 mm) away from any roof surface, as shown in Figure 510.9.1.

(9) Other approved fan, provided it meets all of the following criteria:

(a) The fan meets the requirements of Section 510.9.1(3) and Section 511.1.3.

(b) Its discharge or its extended duct discharge meets the requirements of Section 510.9.1(2). (See Section 511.1.3)

(c) Exhaust fan discharge is directed up and away from the roof surface. {NFPA 96:7.8.2.1}

For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm

FIGURE 510.9.1

UPBLAST FAN CLEARANCES

[NFPA 96: FIGURE 7.8.2.1]

510.9.1.1 Listed Vibration Isolation Connec-
CPC § 510.7.6 Medium relevance — show source text
510.7.6 Listed. For listed grease ducts, see Section 510.4.

510.7.7 Fire Doors. Where openings in the enclosure walls are provided, they shall be protected by listed fire doors of proper rating. Fire doors shall be installed in accordance with NFPA 80. Openings on other listed materials or products shall be clearly identified and labeled according to the terms of the listing and the manufacturer’s instructions and shall be acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.4.1 – 7.7.4.3] The fire door shall be readily accessible, aligned, and of sufficient size to allow access to the rated access

panels on the ductwork. [NFPA 96:7.7.4.4]

510.7.8 Ducts with Enclosure(s). Each duct system shall constitute an individual system serving only exhaust hoods in one fire zone on one floor. Multiple ducts shall not be permitted in a single enclosure unless acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.5.1 – 7.7.5.2]

510.8 Underground Installations. Grease ducts installed underground shall be approved for underground installation. The material of the grease duct shall be corrosion-resistant and shall comply with Section 510.5.1.

510.8.1 Grease Receptacle. The grease duct shall be sloped to drain the grease back to an approved grease collection device. A grease collection device shall be located at the base of the vertical riser.

510.8.2 Cleanouts. For horizontal installations, cleanouts for cleaning and maintenance shall be provided

118 2025 CALIFORNIA MECHANICAL CODE

), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

EXHAUST SYSTEMS

on the top portion of the grease duct in accordance with Section 510.3 and shall be labeled at the interior portion of the duct.

510.9 Termination of Type I Hood Exhaust System. The exhaust system shall terminate as follows:

(1) Outside the building with a fan or duct.

(2) Through the roof or to the roof from outside, as in Section 510.9.1, or through a wall, as in Section 510.9.2. [NFPA 96:7.8.1] 510.9.1 Rooftop Terminations. Rooftop terminations shall be arranged with or provided with the following:

(1) A minimum of 10 feet (3048 mm) of horizontal clearance from the outlet to adjacent buildings, property lines, and air intakes.

(2) A minimum of 5 feet (1524 mm) of horizontal clearance from the outlet (fan housing) to any combustible structure.

(3) A vertical separation of 3 feet (914 mm) above any air intakes within 10 feet (3048 mm) of the exhaust outlet.

(4) The ability to drain grease out of any traps or low points formed in the fan or duct near the termination of the system into a collection container that is noncombustible, closed, rainproof, and structurally sound for the service to which it is applied and that will not sustain combustion.

(5) A grease collection device that is applied to exhaust systems that does not inhibit the performance of any fan.

CPC § 12.8.5 Medium relevance — show source text

(3) The vent cap or a roof assembly shall have a venting capacity not less than that of the pipe to which it is attached. [NFPA 54:12.8.5]

509.7.5 Support of Single-Wall Metal Pipe. All portions of single-wall metal pipe shall be supported for the design and weight of the material employed. [NFPA 54:12.8.6]

509.7.6 Marking. Single-wall metal pipe shall comply with the marking provisions of Section 509.6.5. [NFPA 54:12.8.7]

509.8 Through-the-Wall Vent Termination. Throughthe-wall vent termination shall be in accordance with Section 509.8.1 through Section 509.8.3.

509.8.1 Clearance for Through-the-Wall Vent Ter- mination. The clearance for through-the-wall direct and non-direct vent terminals shall be in accordance with Table 509.8.1 and Figure 509.8.1.

Exception: The clearances in Table 509.8.1 shall not apply to the combustion air intake of a direct vent appliance. [NFPA 54:12.9.1]

» FIGURE 509.8.1 EXIT TERMINALS OF MECHANICAL DRAFT AND DIRECT-VENT VENTING SYSTEMS

[NFPA 54: FIGURE 12.9.1]

100 2025 CALIFORNIA PLUMBING CODE

WATER HEATERS

TABLE 509.8.1

THROUGH-THE-WALL DIRECT-VENT TERMINATION CLEARANCES

[NFPA 54: TABLE 12.9.1]

FIGURE CLEARANCE	CLEARANCE LOCATION	MINIMUM CLEARANCES FOR DIRECT VENT TERMINALS	MINIMUM CLEARANCES FOR NON-DIRECT VENT TERMINALS
A	Clearance above finished grade level, veranda, porch, deck, or balcony	12 inches	12 inches
B	Clearance to window or door that is openable	6 inches for appliances ≤ 10 000 Btu/hr	4 feet below or to side of opening or 1 foot above opening
B	Clearance to window or door that is openable	9 inches for appliances > 10 000 Btu/hr≤ 50 000 Btu/hr	9 inches for appliances > 10 000 Btu/hr≤ 50 000 Btu/hr
B	Clearance to window or door that is openable	12 inches for appliances > 50 000 Btu/hr≤ 150 000 Btu/hr	12 inches for appliances > 50 000 Btu/hr≤ 150 000 Btu/hr
B	Clearance to window or door that is openable	Appliances > 150 000 Btu/hr, in accordance with the appliance manufacturer’s instructions and not less than the clearances specified for non-direct vent terminals in row B	Appliances > 150 000 Btu/hr, in accordance with the appliance manufacturer’s instructions and not less than the clearances specified for non-direct vent terminals in row B
C	Clearance to non-openable window	None unless otherwise specified by the appliance

CBC § 2025 Medium relevance — show source text
; deck:
1″ T&G; filler: 3″ of ashes on1/2″ boards nailed to
joist sides 2″ from bottom; 2″ air space;
membrane:3/8″ gypsum board.|60 psf|36 min|||7|1, 2|1/2| |F/C-W-2|1/2″|12′ clear span, 2″ × 7″ joists 15″ o.c.; deck: 1″
nominal lumber; membrane:1/2″ fiberboard.|60 psf|22 min|||7|1–3|1/4| |F/C-W-3|1/2″|12′ clear span, 2″ × 7″ wood joists 16″ o.c.;
2″ × 11/2″ bridging at center; deck: 1″ T&G;
membrane:1/2″ fiberboard; 2 coats “distemper”
paint.|30 psf|28 min|||7|1, 3,
15|1/3| |F/C-W-4|3/16″|12′ clear span, 2″ × 7″ wood joists 16″ o.c.; 2″ ×
11/2″ bridging at center span; deck: 1″ nominal
lumber; membrane:1/2″ fiberboard under3/16″
gypsum plaster.|30 psf|32 min|||7|1, 2|1/2| |F/C-W-5|5/8″|As per F/C-W-4, except membrane is
5/8″ lime plaster.|70 psf|48 min|||7|1, 2|3/4| |F/C-W-6|5/8″|As per F/C-W-5, except membrane is
5/8″ gypsum plaster on 22 gage3/8″ metal lath.|70 psf|49 min|||7|1, 2|3/4| |F/C-W-7|1/2″|As per F/C-W-6, except membrane is1/2″ fiber-
board under1/2″ gypsum plaster.|60 psf|43 min|||7|1–3|2/3| |F/C-W-8|1/2″|As per F/C-W-7, except membrane is1/2″ gypsum
board.|60 psf|33 min|||7|1–3|1/2| |F/C-W-9|9/16″|12′ clear span, 2″ × 7″ wood joists 15″ o.c.;
2″ × 11/2″ bridging at center; deck: 1″ nominal
lumber; membrane:3/8″ gypsum board;
3/16″ gypsum plaster.|60 psf|24 min|||7|1–3|1/3|

2025 CALIFORNIA EXISTING BUILDING CODE RESOURCE A-101

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

RESOURCE A—GUIDELINES ON FIRE RATINGS OF ARCHAIC MATERIALS AND ASSEMBLIES
CPC § 509.1 Medium relevance — show source text
509.1 Listing . . . . . . . . . . . . . . . . . . . . . . .91

509.2 Connection to Venting Systems . . .91

509.3 Minimum Safe Performance . . . . . .91

509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . . . .92

Table 509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . .92

509.5 Masonry, Metal, and Factory-Built Chimneys . . . . . . . . .93

509.6 Gas Vents . . . . . . . . . . . . . . . . . . . .94

Table 509.6.1 Roof Slope Heights . . . . . . . . . . . .95

509.7 Single-Wall Metal Pipe . . . . . . . . . .97

Table 509.7.3.4(1) Clearances for Connectors . . . . . . .97

Table 509.7.3.4(2) Reduction of Clearances with Specified Forms of Protection . . . .99

509.8 Through-the-Wall Vent Termination . . . . . . . . . . . . . . . . . .100

509.9 Condensation Drain . . . . . . . . . . .100

509.10 Vent Connectors for

Category I Appliances . . . . . . . . .100

Table 509.8.1 Through-the-Wall Direct-Vent Termination Clearances . . . . . . . .101

Table 509.10.1.3 Minimum Thickness for

Galvanized Steel Vent

Connectors for Low-Heat

Appliances . . . . . . . . . . . . . . . . . .102

Table 509.10.1.4 Minimum Thickness for Steel

Vent Connectors for

Medium-Heat Appliances . . . . . . .102

509.11 Vent Connectors for

Category II, Category III, and Category IV Appliances . . . . . . . .104

509.12 Appliances Requiring Draft Hoods . . . . . . . . . . . . . . . . . . . . . .104

509.13 Manually Operated Dampers . . . .104

509.14 Automatically Operated Vent Dampers . . . . . . . . . . . . . . . .104

509.15 Obstructions . . . . . . . . . . . . . . . . .104

510.0 Sizing of Category I Venting Systems . . . . . . . . . . . . . . . . . . . .104

510.1 Additional Requirements to Single Appliance Vent . . . . . . . . .104

510.2 Additional Requirements to Multiple-Appliance Vent . . . . . . . . .106

Table 510.2.1 Vent Connector Maximum

Length . . . . . . . . . . . . . . . . . . . . . .106

Table 510.1.2(1) Type B Double-Wall Gas Vent . . .110

Table 510.1.2(2) Type B Double-Wall Gas Vent . . .113

Table 510.1.2(3) Masonry Chimney . . . . . . . . . . . . .115
CPC § 802.1 Medium relevance — show source text
802.1 Listing . . . . . . . . . . . . . . . . . . . . . . 153

802.2 Connection to Venting Systems . . 153

802.3 Minimum Safe Performance . . . . . 153

802.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . . . . . . 154

802.5 Masonry, Metal, and Factory-Built Chimneys . . . . . . . . . . . . . . . . . . . 154

Table 802.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . . . . . . 155

802.6 Gas Vents. . . . . . . . . . . . . . . . . . . 157

Table 802.6.1 Roof Slope Heights. . . . . . . . . . . . 158

802.7 Single-Wall Metal Pipe . . . . . . . . . 159

Table 802.7.3.3 Clearance for Connectors. . . . . . . 160

802.8 Through-the-Wall Vent Termination . . . . . . . . . . . . . . . . . . 160

802.9 Condensation Drain . . . . . . . . . . . 160

802.10 Vent Connectors for Category I Appliances . . . . . . . . . . . . . . . . . . 160

Table 802.10.1.3 Minimum Thickness for Galvanized

Steel Vent Connectors for Low Heat Appliances . . . . . . . . . . . . . . 161

Table 802.10.1.4 Minimum Thickness for Steel

Vent Connectors for Medium Heat Appliances . . . . . . . . . . . . . . 161

Table 802.8.1 Through-the-Wall Direct Vent Termination Clearances . . . . . . . . 162

802.11 Vent Connectors for Category II, Category III, and Category IV Appliances . . . . . . . . . . . . . . . . . . 164

802.12 Appliances Requiring Draft Hoods . . . . . . . . . . . . . . . . . . 164

802.13 Manually Operated Dampers . . . . 165

802.14 Automatically Operated Vent Dampers . . . . . . . . . . . . . . . . . . . . 165

802.15 Obstruction of Flow. . . . . . . . . . . . 165

803.0 Sizing of Category I Venting Systems . . . . . . . . . . . . . . . . . . . . 165

803.1 Additional Requirements to Single Appliance Vent . . . . . . . . . 165

803.2 Additional Requirements to Multiple-Appliance Vent.. . . . . . . . 167

Table 803.2.1 Vent Connector Maximum

Length. . . . . . . . . . . . . . . . . . . . . . 167

Table 803.1.2(1) Type B Double-Wall Gas Vent . . . 172

Table 803.1.2(2) Type B Double-Wall Gas Vent . . . 175
CPC § 905.1 Medium relevance — show source text
905.1 Grade . . . . . . . . . . . . . . . . . . . . . .190

905.2 Horizontal Drainage Pipe . . . . . . .190

905.3 Vent Pipe Rise . . . . . . . . . . . . . . .190

905.4 Roof Termination . . . . . . . . . . . . .190

905.5 Location of Opening . . . . . . . . . . .190

905.6 Common Vertical Pipe . . . . . . . . .190

906.0 Vent Termination . . . . . . . . . . . . .190

906.1 Roof Termination . . . . . . . . . . . . .190

906.2 Clearance . . . . . . . . . . . . . . . . . . .190

906.3 Use of Roof . . . . . . . . . . . . . . . . .190

906.4 Outdoor Installations . . . . . . . . . . .190

906.5 Joints . . . . . . . . . . . . . . . . . . . . . .190

906.6 Lead . . . . . . . . . . . . . . . . . . . . . . .190

906.7 Frost or Snow Closure . . . . . . . . .190

907.0 Vent Stacks and Relief Vents . . . .190

907.1 Drainage Stack . . . . . . . . . . . . . . .190

907.2 Yoke Vent . . . . . . . . . . . . . . . . . . .190

908.0 Wet Venting . . . . . . . . . . . . . . . . .190

908.1 Vertical Wet Venting . . . . . . . . . . .190

908.2 Horizontal Wet Venting for a Bathroom Group . . . . . . . . . . . . . .191

909.0 Special Venting for Island Fixtures . . . . . . . . . . . . . . . . . . . . .191

909.1 General . . . . . . . . . . . . . . . . . . . . .191

910.0 Combination Waste and Vent

Systems . . . . . . . . . . . . . . . . . . . .191

910.1 Where Permitted . . . . . . . . . . . . . .191

910.2 Approval . . . . . . . . . . . . . . . . . . . .191

910.3 Vents . . . . . . . . . . . . . . . . . . . . . .191

910.4 Connections and Size . . . . . . . . .191

910.5 Vertical Waste Pipe . . . . . . . . . . .191

910.6 Cleanouts . . . . . . . . . . . . . . . . . . .191

910.7 Fixtures . . . . . . . . . . . . . . . . . . . . .191

911.0 Circuit Venting . . . . . . . . . . . . . . .191

911.1 Circuit Vent Permitted . . . . . . . . .191

911.2 Circuit Vent Size and

Connection . . . . . . . . . . . . . . . . . .192
CPC § 407.2.2 Medium relevance — show source text
Plumbing vents shall be located in relation to out-_ door air intakes per California Plumbing Code. The bot- tom of outdoor air intakes shall be located as high as practicable, but not less than 10 feet (3048 mm) above ground level. If installed above the roof, they shall be located 18 inches (457 mm) above roof level or 3 feet (914 mm) above a flat roof where heavy snowfall is anticipated. Outside air intakes located in a below grade areaway shall have the top of the areaway extend a minimum of 10 feet (3048 mm) above grade.

Exceptions:

(1) These dimensions may be reduced if it is demon- strated by the submission of details and calculations that location of intakes with respect to exhausts and

their orientation, or the use of special filters, pro- vides equal performance.

(2) The requirements regarding the bottom of outdoor air intakes and installation through the roof do not apply to skilled nursing facilities, intermediate-care facilities or nonsensitive areas in correctional treat-

ment centers.

407.2.2 Exhaust Outlets. Exhaust outlets shall be located a minimum of 10 feet (3048 mm) above adjoining grade and 10 feet (3048 mm) from doors, occupied areas, and operable windows.

Exception: Airborne infection isolation rooms shall comply with Section 414.1.

407.2.2.1 Hazardous Exhaust Outlets. Haz- ardous exhaust outlets from airborne infection iso- lation rooms, bronchoscopy and sputum collection exhaust, hazardous drug compounding, morgues, autopsy rooms and laboratory chemical fume hoods shall discharge a minimum of 10 feet (3048 mm) above the adjacent roof surface and a minimum of 30 feet (9144.mm) from outdoor air intakes, build- ing openings and areas normally accessible to the public.

407.3 Air Balance.

407.3.1 The ventilation systems shall be designed and balanced to provide the general air balance relationship to adjacent areas, shown in Table 4-A. The ventilation systems shall be balanced in accordance with the latest edition of standards published by the Associated Air Bal- ance Council (AABC), the National Environmental Bal- ancing Bureau (NEBB), or the Testing, Adjusting and Balancing Bureau (TABB). Air balance tolerancing val- ues shall not result in noncompliance of the minimum required pressurization per Table 4-A.

407.4 Air Circulation.

407.4.1 Design of the ventilation system shall provide air movement that is generally from clean to less clean areas.

407.4.1.1 All air distribution devices and supply air outlets shall meet the requirements of ASHRAE 170, Section 6.7.2 and Table 6-2.

407.4.1.2 Supply outlets and return and exhaust air inlets shall be located to prevent short-circuiting.

CPC § 3.1 Medium relevance — show source text

2|1/3| |F/C-3-RC-2|31/4″|31/4″ deep (3540 psi) concrete deck;3/8″ main
reinforcement bars at 51/2″ pitch with7/8″
cover;3/8″ main reinforcement bars at 41/2″
pitch perpendicular with1/2″ cover; 13′1″
span restrained.|195
psf|2 hrs|||7|1, 3, 4|2| |F/C-3-RC-3|31/4 ″|31/4″ deep (4175 psi) concrete deck;3/8″ main
reinforcement bars at 51/2″ pitch with7/8″
cover;3/8″ main reinforcement bars at 41/2″
pitch perpendicular with1/2″ cover; 13′1″
span restrained.|195
psf|31
min|||7|1, 5|1/2| |F/C-3-RC-4|31/4″|31/4″ deep (4355 psi) concrete deck;
3/8″ main reinforcement bars at 51/2″ pitch
with7/8″ cover;3/8″ main reinforcement bars
at 41/2″ pitch perpendicular with1/2″ cover;
13′1″ span restrained.|195
psf|41
min|||7|1, 5, 6|1/2|

2025 CALIFORNIA EXISTING BUILDING CODE RESOURCE A-91

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

RESOURCE A—GUIDELINES ON FIRE RATINGS OF ARCHAIC MATERIALS AND ASSEMBLIES

TABLE 3.1—continued FLOOR/CEILING ASSEMBLIES—REINFORCED CONCRETE	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10
ITEM CODE	ASSEMBLY THICKNESS	CONSTRUCTION DETAILS	PERFORMANCE	PERFORMANCE	REFERENCE NUMBER	REFERENCE NUMBER	REFERENCE NUMBER	NOTES	REC. HOURS
ITEM CODE	ASSEMBLY THICKNESS	CONSTRUCTION DETAILS	LOAD	TIME	PRE-BMS-92	BMS-92	POST-BMS-92	POST-BMS-92	POST-BMS-92
F/C-3-RC-5	31/4″	31/4″ thick (3800 psi) concrete deck;3/8″ main reinforcement bars at 51/2″ pitch with7/8″ cover;3/8″ main reinforcement bars at 41/2″ pitch perpendicular with1/2″ cover; 13′1″ span restrained.	195 psf	1 hr 5 min			7	1, 5	1
F/C-4-RC-6	41/4″	41/4″ thick; 31/4″ (4000 psi) concrete deck; 1″ sprayed asbestos lower surface;

CPC § 507.20 Medium relevance — show source text
507.20 Gas Appliance Pressure Regulators . . . . . . . . . . . . . . . . . . .89

507.21 Bleed Lines for Diaphragm-Type Valves . . . . . . . . . . . . . . . . . . . . . . .89

2025 CALIFORNIA PLUMBING CODE xxxi

), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

TABLE OF CONTENTS

507.22 Combination of Appliances and Equipment . . . . . . . . . . . . . . . .90

507.23 Installation Instructions . . . . . . . . . .90

507.24 Protection of Outdoor

Appliances . . . . . . . . . . . . . . . . . . .90

507.25 Accessibility for Service . . . . . . . . .90

507.26 Clearance to Combustible

Materials . . . . . . . . . . . . . . . . . . . . .90

508.0 Appliances on Roofs, in Attics or Under-Floor Spaces . . . . . . . . . .90

508.1 General . . . . . . . . . . . . . . . . . . . . . .90

508.2 Installation of Appliances on Roofs . . . . . . . . . . . . . . . . . . . . .90

508.3 Appliances on Roofs . . . . . . . . . . .90

508.4 Appliances in Attics and Under-Floor Spaces . . . . . . . . . . . .91

509.0 Venting of Appliances . . . . . . . . . . .91

509.1 Listing . . . . . . . . . . . . . . . . . . . . . . .91

509.2 Connection to Venting Systems . . .91

509.3 Minimum Safe Performance . . . . . .91

509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . . . .92

Table 509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . .92

509.5 Masonry, Metal, and Factory-Built Chimneys . . . . . . . . .93

509.6 Gas Vents . . . . . . . . . . . . . . . . . . . .94

Table 509.6.1 Roof Slope Heights . . . . . . . . . . . .95

509.7 Single-Wall Metal Pipe . . . . . . . . . .97

Table 509.7.3.4(1) Clearances for Connectors . . . . . . .97

Table 509.7.3.4(2) Reduction of Clearances with Specified Forms of Protection . . . .99

509.8 Through-the-Wall Vent Termination . . . . . . . . . . . . . . . . . .100

509.9 Condensation Drain . . . . . . . . . . .100

509.10 Vent Connectors for

Category I Appliances . . . . . . . . .100

Table 509.8.1 Through-the-Wall Direct-Vent Termination Clearances . . . . . . . .101

Table 509.10.1.3 Minimum Thickness for
CPC § 901.0 Medium relevance — show source text
TABLE OF CONTENTS

CHAPTER 9 VENTS . . . . . . . . . . . . . . . . . . . . .187

901.0 General . . . . . . . . . . . . . . . . . . . . .189

901.1 Applicability . . . . . . . . . . . . . . . . . .189

901.2 Vents Required . . . . . . . . . . . . . . .189

901.3 Trap Seal Protection . . . . . . . . . . .189

902.0 Vents Not Required . . . . . . . . . . .189

902.1 Interceptor . . . . . . . . . . . . . . . . . .189

902.2 Bars, Soda Fountains, and Counter . . . . . . . . . . . . . . . . . . . . .189

903.0 Materials . . . . . . . . . . . . . . . . . . . .189

903.1 Applicable Standards . . . . . . . . . .189

903.2 Use of Copper or Copper Alloy Tubing . . . . . . . . . . . . . . . . .189

903.3 Changes in Direction . . . . . . . . . .189

904.0 Size of Vents . . . . . . . . . . . . . . . .189

904.1 Size . . . . . . . . . . . . . . . . . . . . . . . .189

904.2 Length . . . . . . . . . . . . . . . . . . . . . .189

905.0 Vent Pipe Grades and Connections . . . . . . . . . . . . . . . . .190

905.1 Grade . . . . . . . . . . . . . . . . . . . . . .190

905.2 Horizontal Drainage Pipe . . . . . . .190

905.3 Vent Pipe Rise . . . . . . . . . . . . . . .190

905.4 Roof Termination . . . . . . . . . . . . .190

905.5 Location of Opening . . . . . . . . . . .190

905.6 Common Vertical Pipe . . . . . . . . .190

906.0 Vent Termination . . . . . . . . . . . . .190

906.1 Roof Termination . . . . . . . . . . . . .190

906.2 Clearance . . . . . . . . . . . . . . . . . . .190

906.3 Use of Roof . . . . . . . . . . . . . . . . .190

906.4 Outdoor Installations . . . . . . . . . . .190

906.5 Joints . . . . . . . . . . . . . . . . . . . . . .190

906.6 Lead . . . . . . . . . . . . . . . . . . . . . . .190

906.7 Frost or Snow Closure . . . . . . . . .190

907.0 Vent Stacks and Relief Vents . . . .190

907.1 Drainage Stack . . . . . . . . . . . . . . .190

907.2 Yoke Vent . . . . . . . . . . . . . . . . . . .190

Frequently asked questions

Do vents always need to be 6 inches above the roof?

Yes — § 906.1 requires each vent pipe or stack to terminate not less than 6 inches (152 mm) above the roof. That is the baseline vertical requirement; additional clearance rules to openings or intakes may force a higher termination.

If a vent is 12 feet from an intake, does it need to be 3 feet higher?

No — if the vent is at least 10 feet horizontally from the intake, the 10 ft horizontal rule is satisfied and the 3 ft vertical above‑opening option is not required. § 906.2 provides the alternatives.

How does the 25‑foot OSHPD rule work?

For the OSHPD facility classes listed in the code, § 906.2.1 requires that each vent pipe terminate not less than 25 ft (7620 mm) from any air intake or vent shaft. This is a separate, more stringent requirement for those facility types.

Are lot lines treated the same as streets and alleys?

No — § 906.2 requires a vent termination to be not less than 3 ft in every direction from a lot line, but the text explicitly excepts alley and street locations from that lot‑line limitation.

Do gas vents follow the same distances?

Not always. Gas vents and appliance vents have additional specific termination requirements (see § 509.6 and related appliance venting sections) that can require different clearances or caps; consult those sections for appliance vent terminations.

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Related in the CPC

What are the vent pipe rise, grade and connection requirements (drip-back, inverts)?

Permitted vent materials and rules for changes in direction

Installation details: grades, connections and roof termination

California Plumbing Code