The minimum size concrete pad for a two-way cleanout on a building sewer shall be ______________________>.

The minimum size concrete pad for a two-way cleanout on a building sewer is specified to be 18 inches by 18 inches. This size ensures that there is adequate space around the cleanout for maintenance and inspection purposes. A well-sized pad helps prevent soil erosion around the cleanout and provides a stable surface for any required work.

Using a pad that is at least 18 inches on each side allows for sufficient access to the cleanout, ensuring that any necessary plumbing tasks can be performed effectively. Additionally, adhering to this size specification is typically in line with the local plumbing codes, which define and standardize these measurements to enhance safety and functionality in plumbing systems. Thus, the selection of 18 inches by 18 inches as the minimum size promotes both access and structural integrity in maintaining a cleanout in a building's sewer system.