When designing sanitary or storm drainage systems, it is important for the design professional to think about how the drainage system will be maintained. For a long time, the plumbing codes have had requirements for the location and size of openings in the drainage pipes to allow drain cleaning machines to have access to the drainage piping. These access points are called cleanouts.

Plumbing system design professionals should take care to route the drainage piping to allow for cleanouts to be installed at appropriate intervals and to allow access without disrupting the building. Underground building drains, for example, can be routed in corridors or aisles so that cleanouts do not end up covered by casework, cabinets, machinery or equipment that would need to be removed for access to the drainage system. In some cases, drains can be offset to rise up in walls to avoid cleanout covers in high traffic areas.

When drains serving floors above grade require cleanouts, consider the spaces on the floor below where the drainlines change direction. Try not to locate cleanouts in ceiling spaces over sensitive equipment. Cleanouts and drains should be routed to avoid being over food preparation areas, hospital operating rooms, computer rooms or other critical areas.

If the drains must be in the ceiling over sensitive areas, remember that, if there is a blockage, when a plumber removes the cleanout plug, sewage can drain out of the backed up drain and cause damage and possibly the spread of disease and other pathogens to areas below. If cleanouts are over sensitive areas, and if there is no way to avoid having pipes in the ceiling, consider using drain pans under the drains. Also, the designer should discuss with the owner the possibility of turning the cleanouts up to terminate in the floor or in a wall on the floor above.

Drains should be routed far enough away from walls and obstructions that the drain cleaning machine can gain access if needed. Generally, a distance of about three feet from a cleanout to any obstruction or wall is required. Access to drainage cleanouts is becoming more important, as various states have proposed water conservation legislation that will phase in over the next few years and that mandates lower flow rates for various plumbing fixtures. As water flows are reduced, and as waste is diverted away from drainage systems for graywater systems, drainline blockages will increase, and the need for cleanouts will increase.

Two code organizations in the United States develop model codes for adoption by states or local jurisdictions. The International Code Council (ICC) develops and maintains the International Plumbing Code (IPC), and the International Association of Plumbing and Mechanical Officials (IAPMO) develops and maintains the Uniform Plumbing Code (UPC). Various states also develop and maintain their own state codes; however, I am not covering those codes in this article.
Following is the language from these two model plumbing codes that deals with cleanouts for drainage systems.

2012 International Plumbing Code - Cleanout requirements:

IPC - Section 708 Cleanouts

IPC - 708.1 Scope.
This section shall govern the size, location, installation and maintenance of drainage pipe cleanouts.

IPC - 708.2 Cleanout plugs.
Cleanout plugs shall be brass or plastic, or other approved materials. Brass cleanout plugs shall be utilized with metallic drain, waste and vent piping only and shall conform to ASTM A 74, ASME A112.3.1 or ASME A112.36.2M. Cleanouts with plate-style access covers shall be fitted with corrosion-resisting fasteners. Plastic cleanout plugs shall conform to the requirements of Section 702.4. Plugs shall have raised square or countersunk square heads. Countersunk heads shall be installed where raised heads are a trip hazard. Cleanout plugs with borosilicate glass systems shall be of borosilicate glass.

IPC - 708.3 Where required.
Cleanouts shall be located in accordance with Sections 708.3.1 through 708.3.6.

IPC - 708.3.1 Horizontal drains within buildings.
All horizontal drains shall be provided with cleanouts located not more than 100 feet (30 480 mm) apart.

IPC - 708.3.2 Building sewers.
Building sewers shall be provided with cleanouts located not more than 100 feet (30 480 mm) apart, measured from the upstream entrance of the cleanout. For building sewers 8 inches (203 mm) and larger, manholes shall be provided and located not more than 200 feet (60 960 mm) from the junction of the building drain and building sewer, at each change in direction and at intervals of not more than 400 feet (122 m) apart. Manholes and manhole covers shall be of an approved type.

IPC - 708.3.3 Changes of direction.
Cleanouts shall be installed at each change of direction greater than 45 degrees (0.79 rad) in the building sewer, building drain and horizontal waste or soil lines. Where more than one change of direction occurs in a run of piping, only one cleanout shall be required for each 40 feet (12 192 mm) of developed length of the drainage piping.

IPC - 708.3.4 Base of stack.
A cleanout shall be provided at the base of each waste or soil stack.

IPC - 708.3.5 Building drain and building sewer junction.
There shall be a cleanout near the junction of the building drain and the building sewer. The cleanout shall be either inside or outside the building wall and shall be brought up to the finished ground level or to the basement floor level. An approved two-way cleanout is allowed to be used at this location to serve as a required cleanout for both the building drain and building sewer. The cleanout at the junction of the building drain and building sewer shall not be required if the cleanout on a 3-inch (76 mm) or larger diameter soil stack is located within a developed length of 10 feet (3048 mm) of the building drain and building sewer connection. The minimum size of the cleanout at the junction of the building drain and building sewer shall comply with Section 708.7.

IPC - 708.3.6 Manholes.
Manholes serving a building drain shall have secured gas-tight covers and shall be located in accordance with Section 708.3.2.

IPC - 708.4 Concealed piping.
Cleanouts on concealed piping or piping under a floor slab or in a crawl space of less than 24 inches (610 mm) in height or a plenum shall be extended through and terminate flush with the finished wall, floor or ground surface or shall be extended to the outside of the building. Cleanout plugs shall not be covered with cement, plaster or any other permanent finish material. Where it is necessary to conceal a cleanout or to terminate a cleanout in an area subject to vehicular traffic, the covering plate, access door or cleanout shall be of an approved type designed and installed for this purpose.

IPC - 708.5 Opening direction.
Every cleanout shall be installed to open to allow cleaning in the direction of the flow of the drainage pipe or at right angles thereto.

IPC - 708.6 Prohibited installation.
Cleanout openings shall not be utilized for the installation of new fixtures, except where approved and where another cleanout of equal access and capacity is provided.

IPC - 708.7 Minimum size.
Cleanouts shall be the same nominal size as the pipe they serve up to 4 inches (102 mm). For pipes larger than 4 inches (102 mm) nominal size, the size of the cleanout shall be not less than 4 inches (102 mm).

Exceptions:

1. "P” trap connections with slip joints or ground joint connections, or stack cleanouts that are not more than one pipe diameter smaller than the drain served, shall be permitted.

2. Cast-iron cleanout sizing shall be in accordance with referenced standards in Table 702.4, ASTM A 74 for hub and spigot fittings or ASTM A 888 or CISPI 301 for hubless fittings.

IPC - 708.8 Clearances.

Cleanouts on 6-inch (153 mm) and smaller pipes shall be provided with a clearance of not less than 18 inches (457 mm) for rodding. Cleanouts on 8-inch (203 mm) and larger pipes shall be provided with a clearance of not less than 36 inches (914 mm) for rodding.

IPC - 708.9 Access.

Access shall be provided to all cleanouts.

2009 Uniform Plumbing Code — Cleanout requirements:

UPC - 707.0 Cleanouts.

UPC - 707.1 Each cleanout fitting for cast-iron pipe shall consist of a cast-iron or brass body and an approved plug. Each cleanout for galvanized wrought-iron, galvanized steel, copper, or brass pipe shall consist of a brass plug as specified in Table 7-6, or a standard weight brass 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.

UPC - 707.2 Each cleanout fitting and each cleanout plug or cap shall be of an approved type.

UPC - 707.3 Cleanouts shall be designed to be gas and water-tight.

UPC - 707.4 Each horizontal drainage pipe shall be provided with a cleanout at its upper terminal, and each run of piping, that is more than one-hundred (100) feet (30,480 mm) in total developed length, shall be provided with a cleanout for each one-hundred (100) feet (30,480 mm), or fraction thereof, in length of such piping. An additional cleanout shall be provided in a drainage line for each aggregate horizontal change of direction exceeding 135 degrees (2.36 rad).

Exceptions:

Cleanouts shall be permitted to be omitted on a horizontal drain line less than five (5) feet (1,524 mm) in length unless such line is serving sinks or urinals.

Cleanouts shall be permitted to be omitted on any horizontal drainage pipe installed on a slope of 72 degrees (1.26 rad) or less from the vertical angle (one-fifth (1/5) bend).

Excepting the building drain and its horizontal branches, a cleanout shall not be required on any pipe or piping that is above the floor level of the lowest floor of the building.

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 shall be permitted to be substituted for an upper terminal cleanout.

UPC - 707.5 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.

UPC - 707.6 Each cleanout extension shall be considered as drainage piping and each 90 degree (1.6 rad) cleanout extension shall be extended from a wye type fitting or other approved fitting of equivalent sweep.

UPC - 707.7 Each cleanout for an interceptor shall be outside of such interceptor.

UPC - 707.8 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.

UPC - 707.9 Each cleanout in piping two (2) inches (50 mm) or less in size shall be so installed that there is a clearance of not less than twelve (12) inches (305 mm) in front of the cleanout. Cleanouts in piping exceeding two (2) inches (50 mm) shall have a clearance of not less than eighteen (18) inches (457 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 when there is less than eighteen (18) inches (457 mm) vertical overall, allowing for obstructions such as ducts, beams, and piping, and thirty (30) inches of (762 mm) horizontal clearance from the means of access to such cleanout. No under-floor cleanout shall be located exceeding twenty (20) feet (6,096 mm) from an access door, trap door, or crawl hole.

UPC - 707.10 Cleanout fittings shall be not less in size than those given in Table 7-6.

UPC - 707.11 Cleanouts shall be provided for pressure drainage systems as classified under Section 710.7.

UPC - 707.12 Countersunk cleanout plugs shall be installed where raised heads cause a hazard.

UPC - 707.13 When a hubless blind plug is used for a required cleanout, the complete coupling and plug shall be accessible for removal or replacement.

UPC - 707.14 Cleanouts for trap arms shall be installed in accordance with Section 1002.3.

UPC - 1002.3 A trap arm shall be permitted to change direction without the use of a cleanout when such change of direction does not exceed 90 degrees (1.6 rad). All horizontal changes in direction of trap arms shall comply with Section 706.3.

Exception: For trap arms three (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.

With the proposed water conservation legislation, we will all need to make sure there are plenty of cleanouts and proper access to cleanouts because we are going to need them.
Save water safely, my friends.

Ron George is president of Plumb-Tech Design and Consulting Services LLC. He has served as chairman of the International Residential Plumbing & Mechanical Code Committee. Visit www.Plumb-TechLLC.com, email Ron@Plumb-TechLLC.com or phone 734/755-1908.