What minimum size should a cleanout opening be for sewer lines?

The minimum size for a cleanout opening for sewer lines is 100 mm (4 inches). This size is established to ensure there is adequate access for maintenance and inspection of the sewer system. A cleanout allows for the removal of blockages and facilitates the cleaning process, ensuring that sewage can flow freely and efficiently within the plumbing system.

Using a cleanout opening that is too small could hinder access for plumbing professionals and make it difficult to clear any clogs, potentially leading to more significant issues within the plumbing system. The 100 mm size strikes a balance between accessibility and functionality, allowing for the use of standard plumbing tools and equipment during service tasks. This compliance with the plumbing code reflects best practices for maintaining sewer systems and ensuring they operate effectively.