New York City Master Plumbers Practice Exam

The required spacing for plumbing cleanouts in a horizontal drain line is typically every 50 feet for horizontal drains. This spacing is important because cleanouts provide access to the drainage system for maintenance, inspection, and clearing blockages. By having cleanouts at this interval, plumbers can effectively service the drain without needing to open up the entire line, ensuring that any buildup or obstruction can be easily reached.

This standard is consistent with plumbing codes and practices aimed at promoting efficient drainage maintenance while addressing potential issues that may arise in the plumbing system. Having cleanouts spaced every 50 feet helps to ensure that there are convenient points for intervention within the drainage system.