Master Plumber Practice Exam

Under what conditions can cleanouts be omitted on a horizontal drain line?

1. Greater than 2.0 meters

2. Less than 1.5 meters

3. Equal to 2.0 meters

4. None of these

The correct answer is: Less than 1.5 meters

Cleanouts can typically be omitted on horizontal drain lines that are less than 1.5 meters in length because the shorter distance allows for easier access for maintenance and clearing blockages without the need for additional cleanout fittings. Pipes that are less than this specified length are generally considered accessible enough for any necessary inspection or cleaning, assuming the system is installed correctly according to local plumbing codes. In contrast, longer horizontal drain lines, such as those greater than 2.0 meters, would require cleanouts at specified intervals to ensure that maintenance can be conducted efficiently. Cleanouts are essential for longer runs to provide proper access for blockages that may occur further along the line. The same logic applies to a length equal to 2.0 meters. Therefore, the rule generally mandates that cleanouts are necessary to facilitate upkeep and ensure the proper functioning of the plumbing system as its length and complexity increase.