When is a vertical rainwater leader installed inside the building not required to have a cleanout?

The correct answer is that a vertical rainwater leader installed inside the building is not required to have a cleanout when it discharges to daylight, above grade, through the outside wall. This scenario is significant because when rainwater leaders discharge directly to the outside environment, particularly when above grade, the likelihood of accumulation of debris or blockages within that section of the plumbing system is minimized.

In this case, as the water flows freely to the outside, there is less concern about maintaining access for cleaning or removing blockages, which is the primary purpose of a cleanout. Cleanouts become necessary in locations where there is a potential for blockage within the system, typically in horizontal runs or where the water is contained, where debris might collect over time.

Other choices may involve scenarios that typically necessitate a cleanout due to potential for buildup or blockage in the system. For instance, discharging to a sewer manhole or a building sewer involves containment of the water flow and the potential for clogs at joints or bends, thereby requiring access for cleaning. Similarly, the specification regarding diameter less than two inches pertains to codes or standards that may allow smaller diameters to be exempted from certain cleanout requirements, but not usually for vertical sections discharging