6.2 Cleanouts: Locations, Spacing, Size, Clearance & Access
Key Takeaways
Horizontal drains in buildings and building drains need cleanouts at intervals of not more than 100 feet; where manholes are used instead, the interval is 400 feet (IPC 708.1.1).
Building sewers smaller than 8 inches need cleanouts every 100 feet; sewers 8 inches and larger need a manhole within 200 feet of the building drain junction and at intervals of not more than 400 feet (708.1.2).
The junction of the building drain and building sewer needs a cleanout at the junction or within 10 feet of developed length upstream of it (708.1.3).
A horizontal change of direction greater than 45 degrees needs a cleanout, but one cleanout serves all such changes within 40 feet of developed length (708.1.4).
Cleanouts on piping 6 inches and smaller need 18 inches of clearance in front of the opening; on piping 8 inches and larger, 36 inches (708.1.10).
Purpose
Cleanouts give drain-cleaning equipment access to every part of the drainage system. IPC 703.5 sends building sewer cleanouts to Section 708, and 1101.8 applies the same rules to storm drains (except subsurface drainage).
Required locations (IPC 708.1.1 to 708.1.4)
| Section | Location | Rule |
|---|---|---|
| 708.1.1 | Horizontal drainage pipes in buildings and building drains | At intervals of not more than 100 feet. Where manholes are used instead of cleanouts on a building drain, they may be up to 400 feet apart. |
| 708.1.1 exception | Horizontal fixture drain serving a nonremovable trap | No cleanout needed between the trap and its vent connection |
| 708.1.2 | Building sewers smaller than 8 inches | Cleanouts at intervals of not more than 100 feet |
| 708.1.2 | Building sewers 8 inches and larger | A manhole within 200 feet of the building drain and building sewer junction, then manholes at intervals of not more than 400 feet |
| 708.1.3 | Junction of building drain and building sewer | A cleanout at the junction or within 10 feet of developed length upstream of it. Removing a water closet does not count as cleanout access for this rule. |
| 708.1.4 | Horizontal change of direction greater than 45 degrees (horizontal drain, building drain or building sewer) | A cleanout at the change. Where more than one such change occurs within 40 feet of developed length, the cleanout for the first change serves all the changes in that 40 feet. |
Intervals are measured from the cleanout or manhole opening along the developed length of piping to the next fitting that gives cleaning access, or to the end of the drain or sewer.
The 2021 IPC has no separate "cleanout at the base of every stack" rule. That requirement appeared in older editions. Stacks are still served by the junction, spacing and change-of-direction rules.
Size (IPC 708.1.5)
Cleanouts must be the same size as the pipe they serve, except that cleanouts for piping larger than 4 inches need not be larger than 4 inches.
Exceptions:
- A removable P-trap with slip or ground joints can serve as the cleanout for drain piping one size larger than the trap.
- Cleanouts on stacks can be one size smaller than the stack.
- Cleanouts for cast-iron piping can follow the referenced cast-iron fitting standards in Table 702.4.
| Pipe | Minimum cleanout |
|---|---|
| 2 inch | 2 inch (a 1-1/2-inch removable P-trap may serve a 2-inch drain) |
| 3 inch | 3 inch (2 inch if on a 3-inch stack) |
| 4 inch | 4 inch (3 inch if on a 4-inch stack) |
| 6 inch | 4 inch |
| 8 inch and larger | 4 inch where cleanouts are used; large sewers need manholes per 708.1.2 |
708.1.6 equivalent: a fixture trap, or a fixture with an integral trap, that can be removed without altering concealed piping counts as a cleanout.
Arrangement and clearance (IPC 708.1.9 and 708.1.10)
- 708.1.9: a cleanout must allow cleaning only in the direction of drainage flow. Exceptions: test tees used as cleanouts, and a two-way cleanout approved to meet the junction requirement of 708.1.3.
- 708.1.10: cleanouts on piping 6 inches and smaller need a clearance of at least 18 inches from the face of the opening, measured perpendicular to it, to any obstruction. Cleanouts on piping 8 inches and larger need at least 36 inches.
Access (IPC 708.1.11)
- Required cleanouts must not be in concealed locations. Concealed locations include plenums, the inside of walls, floor-ceiling assemblies, below grade, and crawl spaces where the height from the crawl space floor to the nearest obstruction along the path from the crawl space opening to the cleanout is less than 24 inches.
- Cleanouts that open at a finished wall must have the face of the opening within 1-1/2 inches of the finished wall surface.
- Cleanouts below grade must be extended up so the top of the plug is at or above grade.
- A cleanout in a floor or walkway without a trim cover must have a countersunk plug flush with the finished surface.
- 708.1.11.1: trim covers and access doors must be designed and approved for the purpose. Trim cover screws threaded into plugs must be corrosion-resistant. Plugs must not be covered with mortar, plaster or other permanent material.
- 708.1.11.2: where a cleanout must resist vehicle loads, use a floor cleanout assembly meeting ASME A112.36.2M.
Plugs and manholes (IPC 708.1.7 and 708.1.8)
- Cleanout plugs are copper alloy, plastic or other approved material. Plugs for borosilicate glass piping must be borosilicate glass. Copper-alloy plugs meet ASTM A74 and are used only on metallic piping. Plastic plugs meet the plastic fitting standards of Table 702.4.
- Plugs must have a raised square head, a countersunk square head or a countersunk slot head. A plug that will hold a trim cover screw needs a blind threaded hole.
- Manholes and covers must be an approved type. Manholes inside a building need gas-tight covers that require tools for removal.
Prohibited use (IPC 708.1.12)
A threaded cleanout opening may not be used to add a fixture or extend piping, unless another cleanout of equal size is installed with the required access and clearance.
Worked layout
A 4-inch building drain runs 230 feet from the farthest stack to the foundation, with two 90-degree turns 25 feet apart. It then becomes a 4-inch building sewer that runs 140 feet to the street.
- Building drain: cleanouts no more than 100 feet apart, so at least two intermediate cleanouts over 230 feet. One cleanout at the first 90-degree turn serves both turns, because they are within 40 feet.
- Junction: a cleanout at the junction or within 10 feet upstream of it. A two-way cleanout outside the wall is an approved way to meet this rule.
- Building sewer (smaller than 8 inches): a cleanout every 100 feet, so one more cleanout partway along the 140-foot run.
- All cleanouts: 4-inch size, with 18 inches of clearance, and none in a concealed location.
What minimum cleanout size does IPC 708.1.5 require for a 6-inch horizontal building drain?
6 inches
5 inches
3 inches
4 inches
What minimum clearance must be provided in front of a cleanout on a 4-inch sanitary drain under IPC 708.1.10?
18 inches
12 inches
24 inches
36 inches
Under IPC 708.1.3, where must the cleanout serving the junction of the building drain and the building sewer be located?
At the base of the nearest soil or waste stack inside the building
At the junction, or within 10 feet of developed length upstream of it
Anywhere within 100 feet of the building, measured along the building sewer
Inside the building, within 3 feet of the inside face of the foundation wall
Sections you finish are checked off in the contents.