As water flows are reduced and wastewater is diverted away from drainage systems for greywater systems, drain-line blockages will surely increase, as will the need for cleanouts at the appropriate location. I am sure that if you continue to reduce the water flow rates to your plumbing fixtures, you will get to know your local drain cleaning company technicians on a first-name basis. 

Two of the code organizations in the United States develop model codes for adoption by various state and local jurisdictions. The International Code Council (ICC) develops and maintains the International Plumbing Code (IPC). 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 plumbing codes with unique language. This article covers some general issues associated with drain cleaning and a summary of general requirements in the model plumbing codes. 

The plumbing code for a specific jurisdiction may be different; always contact the local code authority if you have questions about dealing with the placement of cleanouts. The following is a discussion and summary of various drainage cleanout issues for drainage systems.

Code Requirements 

The model plumbing codes are developed with the common code format, so cleanouts are typically covered in Chapter 7, Sanitary Drainage Systems, in each model plumbing code. The cleanout requirements in the code generally cover the size, location, installation and maintenance of drainage pipe cleanouts.

Cleanout plugs are generally required to be brass, plastic or other approved noncorrosive and sustainable materials. It is important for the drainage cleanout plug to be recessed. A cleanout access cover designed for the traffic loading should be installed in the floor to allow protection of the cleanout plug from damage and to prevent the transfer of traffic loads to the piping system. 

Brass cleanout plugs

These should be used with metallic drain, waste and vent piping only to prevent the plug’s metallic threads from damaging female threads on plastic piping systems. Cleanout plugs should conform to ASTM A74, ASME A112.3.1 or ASME A112.36.2M. Cleanouts with plate-style access covers should be fitted with corrosion-resistant bolts, threaded rods or fasteners. The cover type should be selected for the appropriate wall type. 

Plastic cleanout plugs

This type of plug should conform to the requirements of the model codes in Chapter 7. Plugs should have raised square or countersunk square heads. Use countersunk heads where raised heads can be damaged. 

I have seen driveways pours with plastic drainage piping coming up to a concrete finished floor elevation where the plastic pipe was installed with a plastic fitting at the driveway elevation and a plastic plug with a raised head was used. The raised plastic head sticking above the finished concrete surface can easily be damaged by vehicle traffic, pedestrian traffic, snow plows, etc. This is why a traffic-rated cleanout access cover should be installed in the concrete slab above the plastic pipe. 

Cleanout plugs in borosilicate glass systems

Cleanout plugs in borosilicate glass acid waste systems should be made of borosilicate glass. The joining method should be in accordance with the manufacturer's recommendations. 

Where Cleanouts are Required 

Access to drainage cleanouts is becoming more important as various water conservation efforts are reducing the amount of water flowing to and from plumbing fixtures. Water reduction has caused a dry drain phenomenon, resulting in more drain-line blockages — less water means less hydraulic depth of flow to move solids down the line. Drain-cleaning businesses have been booming as water conservation efforts continue without research into drain-line transport issues. 

Cleanouts should be located in accordance with the requirements listed in Chapter 7 of the model plumbing codes. Cleanout openings should not be utilized for the installation of new fixtures, except where approved and where another cleanout of equal access and capacity is provided. Every cleanout should be installed to open to allow cleaning in the direction of the flow of the drainage pipe or at right angles to it. 

Access in floors

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 pipe to allow drain-cleaning machines to have access to the drainage piping. These access points are called cleanouts. 

When laying out drainage systems, one 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. 

Another consideration is to offset the drain line in the hallway so the cleanout covers are not a trip hazard or an unsightly object in decorative floor finishes. In some cases, with a little extra effort, drains can be offset to rise in walls to avoid cleanout covers in high traffic areas. 

Access for floors above-grade

When drains serving floors above-grade require cleanouts, consider the spaces on the floor below where the drain lines change direction. Try not to locate cleanouts in ceiling spaces over sensitive equipment or spaces. 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, a significant amount of sanitary sewage can drain out of a large horizontal drain when a plumber removes the cleanout plug. This can cause significant flood damage and possibly the spread of disease and other pathogens to areas below the cleanout. 

If cleanouts are over sensitive areas and if there is no way to avoid having pipe in the ceiling, consider using drain pans under the drains. Also, the designer should discuss with the owner and the architect about the possibility of turning the cleanouts up to terminate in the floor or a wall on the floor above. 

Route drains far enough away from walls and obstructions so that the drain-cleaning machine can gain access if needed. Generally, a distance great enough to allow cleaning-machine access from a cleanout to any obstruction or wall is required for a plumber to feed a drain line snake into the cleanout. 

• Horizontal drains within buildings. All horizontal drains should be provided with cleanouts located not more than 100 ft. (30,480 mm) apart. 

• Base of stack. A cleanout should be provided at the base of each waste or soil stack to allow for cleaning of the horizontal building drain. 

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

• Building drain and sewer junction. A cleanout should be near the junction of the building drain and sewer, either inside or outside the building wall and should be brought up to the finished ground level or the basement floor level. An approved two-way cleanout is generally allowed to be used at this location to serve as a required cleanout for both the building’s drain and sewer lines; however, check with the local code or authority having jurisdiction. 

The reason for the cleanout in this location is because often a building’s sewer line will be required to be larger than its drain line by a local ordinance or the building drain materials may change due to different contracts for interior piping vs. outside piping. Some codes or jurisdictions do not require the cleanout at the junction of the building drain and building sewer if the cleanout on a 3-in. (76 mm) or larger diameter soil stack is located within a developed length of 10 ft. (3,040 mm) of the building drain and sewer connection. 

Verify with the local code and the authority having jurisdiction. The minimum size of the cleanout at the junction of the building drain and building sewer should comply with the plumbing code. 

Concealed piping

Cleanouts on concealed piping or piping under a floor slab or in a crawl space of less than 24 in. (610 mm) in height or a plenum should be extended through and terminate flush with the finished wall, floor or ground surface or should be extended to the outside of the building. Cleanout plugs should not be covered with cement, plaster or any other permanent finish material. 

Where it is necessary to conceal a cleanout or to terminate a one in an area subject to vehicular traffic, the covering plate, access door or cleanout should be of an approved type designed and installed for this purpose.

Changes of direction

The design should have cleanouts 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 should be required for each 40 ft. (12,192 mm) of developed length of the drainage piping. 

This distance between cleanouts should be verified with the local plumbing code and the authority having jurisdiction because new drain-cleaning equipment is making it easier to clean longer distances and around more bends. 

Manholes as cleanouts

Manholes are often required on larger building drains and sewers. Generally, building drains larger than 10 in. require a utility hole within a building for cleanouts and at changes in direction. 

Manholes serving a building drain should have secured, gas-tight covers and vented to an approved location to prevent air from binding (trapping air in the top of the manhole). They also should be located in accordance with the requirements in the local plumbing code. 

Minimum Size of Cleanouts 

Cleanouts should be the same nominal size as the pipe they serve up to 4 in. (102 mm). For pipe larger than 4 in. (102 mm) nominal size, the size of the cleanout should be not less than 4 in. (102 mm). The codes generally allow some exceptions when: 

1. A P-trap connection with slip joints or ground joint connections that can be removed or stack cleanouts that are not more than one pipe diameter smaller than the drain served should be permitted to be removed and utilized as a cleanout. 

2. Cast-iron cleanout sizing should be in accordance with referenced standards in Table 702.4, ASTM A74 for hub and spigot fittings or ASTM A888 or CISPI 301 for hubless fittings. 

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

Provide adequate access to all cleanouts. They should not be covered by drywall, cement or plaster. They should have an access cover extended to the finished wall or floor and located such that there is access to the cleanout opening in the drain with a drain-cleaning machine.

As water conservation efforts continue to move forward, you will soon find a new friend who has a drain-cleaning machine. Make sure you have the cleanouts installed properly. If you don’t, he will charge you a lot of money to dig up your floors or make changes to your plumbing systems to be able to clean out the drainage system. I hope you don’t get on a first-name basis with your local drain-cleaning company employees.