Red Seal Plumbing Practice Exam

What is the minimum size of a clean-out needed on a 6" sanitary building drainage main clean out?

1. 2in

2. 4in

3. 6in

4. 3in

The correct answer is: 4in

A a 2" clean-out would not adequately fit and allow for proper cleaning of a 6" sanitary building drainage main. C: while a 6" clean-out would be the same size as the main, it would not allow for easy access and cleaning as the clean-out would be flush with the main. D: a 3" clean-out would not be large enough to provide proper access and cleaning for a 6" sanitary building drainage main, leaving debris and clogs still present in the pipe. By choosing a 4" clean-out, there is enough space to properly clean and remove debris from the main.