CPC · California Plumbing Code
Are cleanouts, traps and access required on storm drains and leaders?
Short answer for a homeowner: The California Plumbing Code requires a cleanout at the base of every rain leader before it ties into the horizontal drain (see § 1101.13.1). Traps are only required on leaders or storm drains when they discharge to a combined sewer — not when they go to a storm-only sewer — and any trap must be the same size as the horizontal drain and have an accessible cleanout on its outlet side (see § 1101.15 and subsections). file
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
- § 1101.13 says that cleanouts for building storm drains must comply with the cleanout provisions of § 719.0.
- § 1101.13.1 requires a cleanout at the base of any rain leader or conductor before it connects to the horizontal drain.
- § 1101.15 requires traps on leaders and storm drains when they connect to a combined sewer (with stated exceptions); trap sizing and installation location rules are in the same section.
The single most important rule: install a cleanout at the base of every rain leader before it ties into the horizontal drain, and trap leaders/storm drains only when they discharge to a combined sewer.
Requirements in detail
Cleanouts
- The code directs that cleanouts for building storm drains follow the requirements of § 719.0 (see § 1101.13). That is the controlling reference for how and where cleanouts for storm piping must be provided.
- For rain leaders and conductors, a cleanout at the base (i.e., before the leader connects to the horizontal storm drain) is mandated by § 1101.13.1. This is a line-item requirement — a cleanout at that specific location.
Note: § 1101.13 points to § 719.0 for the detailed cleanout rules. The uploaded files list § 719.0 in the table of contents, but the full text of § 719.0 was not included in the retrieved snippets I can quote here; follow § 719.0 for the clearances, materials and orientation required for cleanouts.
Traps on storm drains and leaders
- When required: § 1101.15 requires traps on leaders and storm drains where they are connected to a combined sewer. Floor and area drains that tie into a storm drain must also be trapped.
- Where not required / exceptions: The code includes an exception stating traps are not required where roof drains, rain leaders and other inlets are at locations allowed under § 906.0 (Vent Termination); and § 1101.15.1 specifically says no trap is required for leaders or conductors that connect to a sewer carrying storm water exclusively.
- Trap size: § 1101.15.2 says an individual trap installed for a conductor must be the same size as the horizontal drain to which it connects.
- Method / cleanouts with traps: § 1101.15.3 permits either (a) an individual trap on each storm-water branch, or (b) a single trap in the main storm drain immediately before the connection to the combined building sewer. Where traps are used, they must be provided with an accessible cleanout on the outlet side of the trap.
Key decision table
| Issue / decision | Requirement (what you must do) | Code Reference |
|---|---|---|
| Cleanouts for building storm drains | Provide cleanouts in accordance with the cleanout chapter (see § 719.0) | § 1101.13 |
| Cleanout at base of rain leader/conductor | Install a cleanout at the base before the horizontal connection | § 1101.13.1 |
| Trap required | Trap leaders/storm drains that discharge to a combined sewer | § 1101.15 |
| Trap not required | If leader/conductor connects to a storm-only sewer, no trap required | § 1101.15.1 |
| Trap size | Trap = same size as horizontal drain | § 1101.15.2 |
| Cleanout with trap | Accessible cleanout required on the outlet side of any storm-water trap | § 1101.15.3 |
| Exception for vent termination locations | Traps not required where drains are at locations permitted by § 906.0 | § 1101.15 (Exception) |
Exceptions & special cases
- Location-based exception: if roof drains or leaders are located at positions permitted by § 906.0 (Vent Termination), a trap need not be provided (see the Exception in § 1101.15).
- Storm-only sewers: leaders or conductors that discharge to a sewer carrying storm water exclusively do not require traps per § 1101.15.1. This is the common scenario for separated storm systems.
- Trap sizing and location: when traps are used, size the trap the same as the horizontal drain and either trap each inlet individually or provide a single trap in the main storm drain immediately before the combined sewer tie-in; an accessible cleanout must be provided on the trap outlet side (§ 1101.15.2–.3).
Common mistakes
- Omitting the mandated cleanout at the base of a rain leader before the horizontal connection (required by § 1101.13.1).
- Installing a trap when the leader actually discharges to a storm-only sewer (not required under § 1101.15.1).
- Failing to provide a cleanout on the outlet side of a storm-water trap when a trap is installed (required by § 1101.15.3).
- Sizing the trap incorrectly — traps for individual conductors must be the same size as the horizontal drain they serve (§ 1101.15.2).
- Relying on unrelated cleanout guidance: § 1101.13 points to § 719.0 for the detailed cleanout rules — use § 719.0 (not generic sanitary cleanout text) for building storm-drain cleanout specifics. The retrieved files show § 719.0 in the table of contents but do not include full § 719.0 text in the snippets I can quote here.
Worked example
Scenario: A rain leader from a roof is a 4‑inch conductor and will connect to a building storm drain that then ties into a combined building sewer.
What to install:
- Put a cleanout at the base of the 4‑inch leader before the horizontal connection (per § 1101.13.1).
- Because the storm drain ties into a combined sewer, provide a trap. Per § 1101.15.2, the trap for that individual conductor must be 4 inches (same size as the horizontal drain).
- Install the trap either (a) directly on that conductor branch, or (b) provide a single trap in the main storm drain immediately before the combined sewer connection; in either case provide an accessible cleanout on the outlet side of the trap per § 1101.15.3.
If instead the building storm drain connects to a storm-only sewer, do not install the trap (§ 1101.15.1), but still provide the base-of-leader cleanout required by § 1101.13.1. file
Related provisions
- § 719.0 — Cleanouts (referenced by § 1101.13) — see table of contents entry.
- § 1101.12 — Roof drainage (context for leaders, conductors and roof drains).
- § 1101.16 — Leaders, conductors, and connections (separation from soil/waste/vent and protection).
- § 906.0 — Vent Termination (locations that can affect whether traps are required per the exception to § 1101.15).
- § 1103.0 — Sizing of leaders, conductors and storm drains (affects selecting trap/horizontal drain size).
Code references
Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:
CPC § 1101.12.2.2 High relevance — show source text
1101.12.2.2 Secondary Roof Drain. Secondary roof drains shall be provided. The secondary roof drains shall be located not less than 2 inches (51 mm) above the roof surface. The maximum height of the roof drains shall be a height to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by Section 1101.12.1. The secondary roof drains shall connect to a piping system in accordance with Section 1101.12.2.2.1 or Section 1101.12.2.2.2.
1101.12.2.2.1 Separate Piping System. The secondary roof drainage system shall be a
206 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
STORM DRAINAGE
separate system of piping, independent of the primary roof drainage system. The discharge shall be above grade, in a location observable by the building occupants or maintenance personnel. Secondary roof drain systems shall be sized in accordance with Section 1101.12.1
based on the rainfall rate for which the primary system is sized. 1101.12.2.2.2 Combined System. The secondary roof drains shall connect to the vertical piping of the primary storm drainage conductor downstream of the last horizontal offset located below the roof. The primary storm drainage system shall connect to the building storm water that connects to an underground public storm sewer. The combined secondary and primary roof drain systems shall be sized in accordance with Section 1103.0 based on double the rain fall rate for the local area.
1101.13 Cleanouts. Cleanouts for building storm drains shall comply with the requirements of Section 719.0 of this code.
1101.13.1 Rain Leaders and Conductors. Rain leaders and conductors connected to a building storm sewer shall have a cleanout installed at the base of the
leader or conductor before it connects to the horizontal
drain.
1101.14 Rainwater Sumps. Rainwater sumps serving “public use” occupancy buildings shall be provided with dual pumps arranged to function alternately in the case of overload or mechanical failure. Pumps rated 600 V or less shall comply with UL 778 and shall be installed in accordance with the manufacturer’s installation instructions.
1101.15 Traps on Storm Drains and Leaders. Leaders and storm drains, where connected to a combined sewer, shall be trapped. Floor and area drains connected to a storm drain shall be trapped.
Exception: Traps shall not be required where roof drains, rain leaders, and other inlets are at locations permitted under Section 906.0, Vent Termination.
1101.15.1 Where Not Required. No trap shall be required for leaders or conductors that are connected to a sewer carrying storm water exclusively. 1101.15.2 Trap Size. Traps, where installed for individual conductors, shall be the same size as the horizontal drain to which they are connected.
1101.15.3 Method of Installation of Combined Sewer. Individual storm-water traps shall be installed on the stormwater drain branch serving each storm-water inlet, or a single trap shall be installed in the main storm drain just before its connection with the combined building sewer. Such traps shall be provided with an accessible cleanout on the outlet side of the trap.
CPC § 1101.13.1 High relevance — show source text
1101.13.1 Rain Leaders and Conductors. Rain leaders and conductors connected to a building storm sewer shall have a cleanout installed at the base of the
leader or conductor before it connects to the horizontal
drain.
1101.14 Rainwater Sumps. Rainwater sumps serving “public use” occupancy buildings shall be provided with dual pumps arranged to function alternately in the case of overload or mechanical failure. Pumps rated 600 V or less shall comply with UL 778 and shall be installed in accordance with the manufacturer’s installation instructions.
1101.15 Traps on Storm Drains and Leaders. Leaders and storm drains, where connected to a combined sewer, shall be trapped. Floor and area drains connected to a storm drain shall be trapped.
Exception: Traps shall not be required where roof drains, rain leaders, and other inlets are at locations permitted under Section 906.0, Vent Termination.
1101.15.1 Where Not Required. No trap shall be required for leaders or conductors that are connected to a sewer carrying storm water exclusively. 1101.15.2 Trap Size. Traps, where installed for individual conductors, shall be the same size as the horizontal drain to which they are connected.
1101.15.3 Method of Installation of Combined Sewer. Individual storm-water traps shall be installed on the stormwater drain branch serving each storm-water inlet, or a single trap shall be installed in the main storm drain just before its connection with the combined building sewer. Such traps shall be provided with an accessible cleanout on the outlet side of the trap.
1101.16 Leaders, Conductors, and Connections. Leaders or conductors shall not be used as soil, waste, or vent pipes nor shall soil, waste, or vent pipes be used as leaders or conductors.
1101.16.1 Protection of Leaders. Leaders installed along alleyways, driveways, or other locations where exposed to damage shall be protected by metal guards, recessed into the wall, or constructed from the ferrous pipe. 1101.16.2 Combining Storm with Sanitary Drainage. The sanitary and storm drainage system of a building shall be entirely separate, except where a combined sewer is used, in which case the building storm drain shall be connected in the same horizontal plane through a single wye fitting to the combined building sewer not less than 10 feet (3048 mm) downstream from a soil stack.
1102.0 Roof Drains.
1102.1 Applications. Roof drains shall be constructed of aluminum, cast-iron, copper alloy of not more than 15 percent zinc, leaded nickel bronze, stainless steel, ABS, PVC, polypropylene, polyethylene, or nylon and shall comply with ASME A112.3.1 or ASME A112.6.4.
1102.2 Dome Strainers Required. Roof drains shall have domed strainers.
Exception: Roof drain strainers for use on sun decks, parking decks, and similar areas that are normally serviced and maintained, shall be permitted to be of the flat surface type. Such roof drain strainers shall be level with the deck.
CPC § 407.2.3 High relevance — show source text
LAVATORY FAUCETS
Common and public use areas . . . . . . . . . . . . . .407.2.3 Maximum flow rate . . . . . . . . . . . . . . . . .407.2.1, 407.2.2
Metering faucet . . . . . . . . . . . . . . . . . . . . . . . . . .407.2.4
Public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .407.2.1
Residential . . . . . . . . . . . . . . . . . . . . . . . . . . . . .407.2.2
LAWN SPRINKLERS . . . . . . . . .Table 610.3, Table A 103.1,
A 103.2, M 102.5
LEAD
Allowable lead contents . . . . . . . . . . . . . .604.2, 604.2.1
Bends and traps . . . . . . . . . . . . . . . . . . . . .701.5, 906.6 Closet rings . . . . . . . . . . . . . . . . . . . . . . . . . . . .402.6.1
Flashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1102.3.1
Roof drains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1102.1
Sheet . . . . . . . . . . . . . . . . . . . . . . .408.8.3, 701.5, 906.6
Water supply . . . . . . . . . . . . . . . . . . . . . .604.2, 604.2.1
LEADERS
Cleanouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.13
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.0
Installed outside . . . . . . . . . . . . . . . . . . . . . . . . .1101.4.3
Leaders, conductors, and connections . . . . . . . .1101.16 Roof drainage . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.12 Size of leaders, conductors, and
storm drains . . . . . . . . . . . . . . . . . . . . . . . . . . .1103.0
Sizing roof drains, leaders, and vertical rainwater piping . . . . . . . . . . . . .Table 1103.1 Traps on storm drains and leaders . . . . . . . . . . .1101.15
LIMITED-DENSITY OWNER-BUILT
RURAL DWELLING
Connections to plumbing system . . . . . . . . . . . . . .304.1
CPC § 718.2 High relevance — show source text
TABLE OF CONTENTS
718.2 Support . . . . . . . . . . . . . . . . . . . . .176
718.3 Protection from Damage . . . . . . .176
719.0 Cleanouts . . . . . . . . . . . . . . . . . . .177
719.1 Locations . . . . . . . . . . . . . . . . . . .177
719.2 No Additional Cleanouts . . . . . . . .177
719.3 Building Sewer Cleanouts . . . . . .177
719.4 Cleaning . . . . . . . . . . . . . . . . . . . .177
719.5 Access . . . . . . . . . . . . . . . . . . . . .177
719.6 Manholes . . . . . . . . . . . . . . . . . . .177
720.0 Sewer and Water Pipes . . . . . . . .177
720.1 General . . . . . . . . . . . . . . . . . . . . .177
721.0 Location . . . . . . . . . . . . . . . . . . . .177
721.1 Building Sewer . . . . . . . . . . . . . . .177
Table 721.1 Minimum Horizontal Distance Required from Building Sewer . . . .177
721.2 Abutting Lot . . . . . . . . . . . . . . . . .177
722.0 Abandoned Sewers and Sewage Disposal Facilities . . . . . .177
722.1 Building (House) Sewer . . . . . . . .177
722.2 Cesspools, Septic Tanks, and Seepage Pits . . . . . . . . . . . . .178
722.3 Filling . . . . . . . . . . . . . . . . . . . . . .178
722.4 Ownership . . . . . . . . . . . . . . . . . .178
722.5 Disposal Facilities . . . . . . . . . . . . .178
723.0 Building Sewer Test . . . . . . . . . . .178
723.1 General . . . . . . . . . . . . . . . . . . . . .178
724.0 Meat and Poultry Processing Plant Drainage . . . . . . . . . . . . . . .178
725.0 Collection Center and
Facilities Drainage . . . . . . . . . . . .178
726.0 Drainage and Plumbing, General . . . . . . . . . . . . . . . . . . . . .178
727.0 Emergency Sanitary Drainage . . .178
CHAPTER 8 INDIRECT WASTES . . . . . . . . . .179
801.0 General . . . . . . . . . . . . . . . . . . . . .181
801.1 Applicability . . . . . . . . . . . . . . . . . .181
801.2 Air Gap or Air Break Required . . .181
801.3 Food and Beverage Handling Establishments . . . . . . .181
801.4 Bar and Fountain Sink Traps . . . .181
CPC § 1101.1 High relevance — show source text
1101.1 Applicability . . . . . . . . . . . . . . . . . .205
1101.2 Where Required . . . . . . . . . . . . . .205
1101.3 Storm Water Drainage to Sanitary Sewer Prohibited . . . . . .205
1101.4 Material Uses . . . . . . . . . . . . . . . .205
Table 1101.4.6 Materials for Subsoil Drainpipe and Fittings . . . . . . . . . . . . . . . . . .205
1101.5 Expansion Joints Required . . . . . .205
1101.6 Subsoil Drains . . . . . . . . . . . . . . .205
1101.7 Building Subdrains . . . . . . . . . . . .206
1101.8 Areaway Drains . . . . . . . . . . . . . .206
1101.9 Window Areaway Drains . . . . . . .206
1101.10 Filling Stations and Motor Vehicle Washing Establishments . . . . . . . . . . . . . . .206
1101.11 Paved Areas . . . . . . . . . . . . . . . . .206
1101.12 Roof Drainage . . . . . . . . . . . . . . .206
1101.13 Cleanouts . . . . . . . . . . . . . . . . . . .207
1101.14 Rainwater Sumps . . . . . . . . . . . . .207
1101.15 Traps on Storm Drains and Leaders . . . . . . . . . . . . . . . . . . . . .207
1101.16 Leaders, Conductors, and
Connections . . . . . . . . . . . . . . . . .207
1102.0 Roof Drains . . . . . . . . . . . . . . . . . .207
1102.1 Applications . . . . . . . . . . . . . . . . .207
1102.2 Dome Strainers Required . . . . . . .207
1102.3 Roof Drain Flashings . . . . . . . . . .207
1103.0 Size of Leaders, Conductors,
and Storm Drains . . . . . . . . . . . . .207
1103.1 Vertical Conductors and
Leaders . . . . . . . . . . . . . . . . . . . . .207
1103.2 Size of Horizontal Storm
Drains and Sewers . . . . . . . . . . . .207
1103.3 Size of Roof Gutters . . . . . . . . . . .207
1103.4 Side Walls Draining onto a Roof . . . . . . . . . . . . . . . . . .207
Table 1103.1 Sizing Roof Drains, Leaders, and Vertical Rainwater Piping . . .208
1104.0 Values for Continuous Flow . . . . .208
1104.1 General . . . . . . . . . . . . . . . . . . . . .208
1105.0 Controlled-Flow Roof
Drainage . . . . . . . . . . . . . . . . . . . .208
CPC § 408.8.3 High relevance — show source text
Sheet . . . . . . . . . . . . . . . . . . . . . . .408.8.3, 701.5, 906.6
Water supply . . . . . . . . . . . . . . . . . . . . . .604.2, 604.2.1
LEADERS
Cleanouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.13
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.0
Installed outside . . . . . . . . . . . . . . . . . . . . . . . . .1101.4.3
Leaders, conductors, and connections . . . . . . . .1101.16 Roof drainage . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.12 Size of leaders, conductors, and
storm drains . . . . . . . . . . . . . . . . . . . . . . . . . . .1103.0
Sizing roof drains, leaders, and vertical rainwater piping . . . . . . . . . . . . .Table 1103.1 Traps on storm drains and leaders . . . . . . . . . . .1101.15
LIMITED-DENSITY OWNER-BUILT
RURAL DWELLING
Connections to plumbing system . . . . . . . . . . . . . .304.1
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.0
Disposal of liquid waste . . . . . . . . . . . . . . . . . . . . .303.1 Water supply and flushing . . . . . . . . . . . . . . . . . . .601.2 LIQUEFIED PETROLEUM
GAS (LP-GAS) . . . . . . . . . . . . . . . 214.0, 1202.1, 1208.4.1,
1208.5.6.3, 1208.5.10.4,
1212.11, E 401.2,
E 403.1, E 403.10
LIQUID WASTES . . . . . . . . . . . . . . . . .214.0, 303.0, L 302.0
LISTED . . . . . . . . . . . . . . . . . . . . . . . .214.0, 301.2, 402.6.2,
501.1
LISTING AGENCY . . . . . . . . . . . . . . . . . . . . . . .214.0, 301.2
LOCATION OF
Backwater valves . . . . . . . . .710.1, 710.3, 710.4, 710.6,
1006.0, 1101.6.4, 1503.2.3,
1503.9.1, 1503.9.7
CPC § 707.1 High relevance — show source text
TABLE 707.1
CLEANOUTS
For SI units: 1 inch = 25 mm
TABLE 707.2 CLEANOUT MATERIALS FOR DRAIN, WASTE, AND VENT
1 [HCD 1 & HCD 2] ABS and PVC installations are limited to not more
than two stories of areas of residential accommodation.
172 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
SANITARY DRAINAGE
Exceptions:
(1) Cleanouts shall be permitted to be omitted on a horizontal drain line less than 5 feet (1524 mm) in length unless such line is serving sinks or urinals.
(2) Cleanouts shall be permitted to be omitted on a horizontal drainage pipe installed on a slope of 72 degrees (1.26 rad) or less from the vertical angle (one-fifth bend).
(3) Excepting the building drain, its horizontal branches, kitchen sinks, and urinals, a cleanout shall not be required on a pipe or piping that is above the floor level of the lowest floor of the building.
(4) An approved type of two-way cleanout fitting, installed inside the building wall near the connection between the building drain and the building sewer or installed outside of a building at the lower end of a building drain and extended to grade, shall be permitted to be substituted for an upper terminal cleanout.
707.4.1 Load Rated Cover. Cleanout floor covers and top rims meant to take loads shall be rated for the loading in accordance with ASME A112.36.2M. 707.5 Cleaning. Each cleanout shall be installed so that it opens to allow cleaning in the direction of flow of the soil or waste or at right angles thereto and, except in the case of wye branch and end-of-line cleanouts, shall be installed vertically above the flow line of the pipe.
707.6 Extension. Each cleanout extension shall be considered as drainage piping and each 90 degree (1.57 rad) cleanout extension shall be extended from a wye-type fitting or other approved fitting of equivalent sweep.
707.7 Interceptor. Each cleanout for an interceptor shall be outside of such interceptor.
707.8 Access. Each cleanout, unless installed under an approved cover plate, shall be above grade, readily accessible, and so located as to serve the purpose for which it is intended. Cleanouts located under cover plates shall be so installed as to provide the clearances and accessibility required by this section.
707.9 Clearance. Each cleanout in piping 2 inches (50 mm) or less in size shall be so installed that there is a clearance of not less than 18 inches (457 mm) by 18 inches (457 mm) in front of the cleanout. Cleanouts in piping exceeding 2 inches (50 mm) shall have a clearance of not less than 24 inches (610 mm) by 24 inches (610 mm) in front of the cleanout. Cleanouts in under-floor piping shall be extended to or above the finished floor or shall be extended outside the building where there is less than 18 inches (457 mm) vertical overall, allowing for obstructions such as ducts, beams, and piping, and 30 inches of (762 mm) horizontal clearance from the means of access to such cleanout.
CPC § 706.2 High relevance — show source text
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.
707.1 Plug. Each cleanout fitting for cast-iron pipe shall consist of a cast-iron or copper alloy body and an approved plug. Each cleanout for galvanized wrought iron, galvanized steel,
copper, or copper alloy pipe shall consist of a plug as specified in Table 707.1, or a standard weight copper alloy cap, or an approved ABS or PVC plastic plug, or an approved stainless steel cleanout or plug. Plugs shall have raised square heads or approved countersunk rectangular slots.
TABLE 707.1
CLEANOUTS
SIZE OF PIPE
(inches)SIZE OF CLEANOUT
(inches)THREADS
(per inches)
11⁄211⁄2 111⁄2
211⁄2 111⁄2
21⁄221⁄2 8
321⁄2 8
4 & larger31⁄2 8 For SI units: 1 inch = 25 mm
707.2 Approved. Each cleanout fitting and each cleanout plug or cap shall be of an approved type. A list of approved standards for cleanouts are referenced in Table 707.2.
TABLE 707.2 CLEANOUT MATERIALS FOR DRAIN, WASTE, AND VENT
CPC § 1004.2 High relevance — show source text
1004.2 Movable Parts. Bladders, check valves or another type of devices with moveable parts shall be prohibited to serve as a trap.
1005.0 Trap Seals. 1005.1 General. Each fixture trap shall have a liquid seal of not less than 2 inches (51 mm) and not more than 4 inches (102 mm), except where a deeper seal is found necessary by the Authority Having Jurisdiction. Traps shall be set true with respect to their liquid seals and, where necessary, they shall be protected from freezing.
1006.0 Floor Drain Traps. 1006.1 General. Floor drains shall connect into a trap so constructed that it can be readily cleaned and of a size to serve efficiently the purpose for which it is intended. The drain inlet shall be so located that it is in full view. Where subject to the reverse flow of sewage or liquid waste, such drains shall be equipped with an approved backwater valve.
1007.0 Trap Seal Protection. 1007.1 General. Floor drain or similar traps directly connected to the drainage system and subject to infrequent use shall be protected with a trap seal primer, except where not deemed necessary for safety or sanitation by the Authority Having Jurisdiction. Trap seal primers shall be accessible for maintenance.
1007.2 Trap Seal Primers. Potable water supply trap seal primer valves shall comply with ASSE 1018. Drainage or electronic design type trap seal primer devices shall comply with ASSE 1044 or IAPMO PS 76.
1008.0 Building Traps. 1008.1 General. Building traps shall not be installed except where required by the Authority Having Jurisdiction. Each building trap where installed shall be provided with a cleanout and with a relieving vent or fresh-air intake on the inlet side of the trap, which needs not be larger than one-half the diameter of the drain to which it connects. Such relieving vent or fresh-air intake shall be carried above grade and terminate in a screened outlet located outside the building.
1009.0 Interceptors (Clarifiers) and Separators.
1009.1 Where Required. Interceptors (clarifiers) (including grease, oil, sand, solid interceptors, etc.) shall be required
by the Authority Having Jurisdiction where they are necessary for the proper handling of liquid wastes containing grease, flammable wastes, sand, solids, acid or alkaline substances, or other ingredients harmful to the building drainage system, the public or private sewer, or to public or private sewage disposal. A list of acceptable interceptor standards is referenced in Table 1009.1.
TABLE 1009.1 APPROVED INTERCEPTORS (CLARIFIERS)
CPC § 2025 High relevance — show source text
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
FORMAT OF THE UNIFORM PLUMBING CODE
Chapter 10 Traps and Interceptors.
Chapter 10 regulates the material, design, and installation of traps, interceptors, and separators. Traps are required on drainage type plumbing fixtures and must be self-scouring without interior partitions. Interceptors, on the other hand, are designed to control what goes down a drain. Interceptors are used to keep harmful substances from entering the sanitary drainage system, such as grease, sand, oil and other materials. The retained materials need periodic removal to maintain efficiency and function of the separating device. The capacity of an interceptor is based on retention and flow rate. There are many types of interceptors that are used at beauty salons, hospitals, meat, fish or foul packaging, refineries, repair garages, gas stations, car washing facilities, various plants, factories, and processing sites. The designer of the building is responsible for locating interceptors with the expectation for the frequency of maintenance, ease of cleaning and floor space for equipment.
Chapter 11 Storm Drainage.
Chapter 11 regulates the removal of stormwater from roofs, yards, paved areas, and similar areas. The objective of storm drainage systems is to provide a conduit or channel through which runoff will be carried from a point of collection to a point of disposal; this protects the property and the public from the uncontrolled flow of runoff and ensures that drains and inlets are adequately sized to receive the volume of runoff that flows to the drains. For the purpose of system design, it’s necessary to specify the duration of a selected storm. All methods used to determine volumes and peak flow use historical data. Drain location must be coordinated with the architectural design of the building. When selecting the type of roof drain to use, the roof construction and its thickness, along with the intended use of the roof, are required. Where the roof perimeter extends above the roof in such a manner that water is entrapped and causes ponding, or if any portion of the roof is designed so water can pond, secondary drainage is required. Where secondary drainage is required, scuppers, or a secondary system of roof drains and pipes, are installed to prevent the accumulation of excessive rainwater.
Chapter 12 Fuel Gas Piping.
Chapter 12 regulates the installation of gas piping in a building, structure or within the property lines of buildings up to 5 psi. Gas piping systems must supply the minimum volume of gas required by each gas appliance to perform their proper operation under working conditions without exceeding the maximum pressure specified by each manufacturer. Because of the hazards associated with fuel gas, it is important to ensure the gas system has been inspected and tested, and that it is safe to turn on the gas supply to the building.
Chapter 13 Health Care Facilities and Medical Gas and Medical Vacuum Systems.
Chapter 13 regulates the installation, inspection, testing, maintenance, performance, and safe practices for medical gas and vacuum systems located in health care facilities. This chapter addresses the installation and maintenance of health care fixtures, devices, and equipment. The purpose of medical gas and medical vacuum systems is to provide safe and sufficient flows at required pressures to the medical gas outlet or vacuum inlet terminals. System design and layout should allow convenient access by the medical staff to outlet and inlet terminals, valves, and equipment during patient care or emergencies, as safety is of primary concern.
Chapter 14 Firestop Protection.
CPC § 1101.4.2.2 Medium relevance — show source text
1101.4.2.2 [OSHPD 1, 2, 3, 4 & 5] ABS and PVC installations are not allowed.
1101.4.3 Leaders. Leaders installed outside shall comply with the applicable standards referenced in Table 701.2 for aboveground drain, waste, and vent pipe; aluminum sheet metal; galvanized steel sheet metal; or copper sheet metal. 1101.4.4 Underground Building Storm Drains. Underground building storm drains shall comply with the applicable standards referenced in Table 701.2 for underground drain, waste, and vent pipe. 1101.4.5 Building Storm Sewers. Building storm sewers shall comply with the applicable standards referenced in Table 701.2 for building sewer pipe. 1101.4.6 Subsoil Drains. Subsoil drains shall be open jointed, perforated, or both and constructed of materials in conformance with Table 1101.4.6.
TABLE 1101.4.6
MATERIALS FOR SUBSOIL DRAINPIPE AND FITTINGS
MATERIAL REFERENCED STANDARD(S)
PEASTM F667
PVCASTM D2729 Vitrified Clay (Extra strength) ASTM C4, ASTM C700 1101.5 Expansion Joints Required. Expansion joints or sleeves shall be provided where warranted by temperature variations or physical conditions. 1101.6 Subsoil Drains. Subsoil drains shall be provided around the perimeter of buildings having basements, cellars, crawl spaces, or floors below grade. Such subsoil drains shall be permitted to be positioned inside or outside of the footing, shall be of perforated or open-jointed approved drain tile or pipe, not less than 3 inches (80 mm) in diameter, and shall be laid in gravel, slag, crushed rock, approved [3] ⁄ 4 of an inch (19.1 mm) crushed, recycled glass aggregate, or other approved porous material with not less than 4 inches (102 mm) surrounding the pipe. Filter media shall be provided for exterior subsoil piping. Exception: [HCD 1 & HCD 2] Subsoil drains are mandatory only when required by the Authority Having Jurisdiction due to geological conditions.
TABLE 1101.4.6
MATERIALS FOR SUBSOIL DRAINPIPE AND FITTINGS
2025 CALIFORNIA PLUMBING CODE 205
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
STORM DRAINAGE
1101.6.1 Discharge. Subsoil drains shall be piped to a storm drain, to an approved water course, to the front street curb or gutter, to an alley, or the discharge from the subsoil drains shall be conveyed to the alley by a concrete gutter. Where a continuously flowing spring or groundwater is encountered, subsoil drains shall be piped to a storm drain or an approved water course. 1101.6.2 Sump. Where it is not possible to convey the drainage by gravity, subsoil drains shall discharge to an accessible sump provided with an approved automatic electric pump.
CPC § 10-3 Medium relevance — show source text
1003 Building Elements and Materials . . . . . . . . . . . . . . . . 10-3
1004 Fire Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3
1005 Means of Egress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3
1006 Structural. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3
1007 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
1008 Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
1009 Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
1010 Other Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5
1011 Change of Occupancy Classification . . . . . . . . . . . . . 10-5
CHAPTER 11 ADDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . .11-3
1101 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3
1102 Heights and Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3
1103 Structural. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4
1104 Energy Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4
CHAPTER 12 HISTORIC BUILDINGS . . . . . . . . . . . . . . . . . .12-1
xviii 2025 CALIFORNIA EXISTING BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
CHAPTER 13 PERFORMANCE COMPLIANCE METHODS. . 13-3
1301 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3
1302 Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3
1303 Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-4
Frequently asked questions
Do I always need a cleanout at every roof drain leader?
Yes — a cleanout at the base of each rain leader or conductor before it connects to the horizontal drain is required by § 1101.13.1.
When are traps required on storm leaders?
Traps are required when leaders or storm drains are connected to a combined sewer; they are not required where the sewer carries only storm water (see § 1101.15 and § 1101.15.1).
How big must a trap be for a leader?
When a trap is installed for an individual conductor, it must be the same size as the horizontal drain to which it connects (see § 1101.15.2).
If I install one trap in the main storm drain, do I still need cleanouts?
Yes — whether you use individual traps or a single main trap, an accessible cleanout is required on the outlet side of the trap per § 1101.15.3. Also provide the leader-base cleanout required by § 1101.13.1. file
Where can I find the detailed cleanout dimensions, materials and clearance rules?
§ 1101.13 directs you to § 719.0 for the detailed cleanout requirements; the code index/table of contents lists § 719.0. The specific 719.0 text wasn’t included in the retrieved snippets here, so consult the full CPC § 719.0 for the exact clearances and material requirements. file
More in California Plumbing Code
- Administration
- Definitions
- General Regulations
- Plumbing Fixtures and Fixture Fittings
- Water Heaters
- Water Supply and Distribution
- Sanitary Drainage (Drain, Waste, and Vent)
- Indirect Wastes
- Vents
- Traps and Interceptors
- Storm Drainage
- Fuel Gas Piping
- Health Care Facilities — Medical Gas and Medical Vacuum Systems
- Alternate Water Sources and Nonpotable Rainwater Catchment Systems
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