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What must be the opening size of a cleanout when installed in relation to the drainage line?

  1. Perpendicular

  2. Opposite

  3. Parallel

  4. At right angles

The correct answer is: At right angles

The correct answer indicates that the cleanout must be installed at right angles to the drainage line. This orientation is important because it facilitates easier access for maintenance and cleaning. By having the cleanout at right angles, it allows for a direct line of sight and access to the interior of the drainage system, making it more effective for clearing blockages and performing inspections. When a cleanout is positioned at right angles, it aligns better with the flow of the waste water, thereby reducing the risk of accumulation at the point of entry. In contrast, positioning it in other orientations, such as perpendicular, opposite, or parallel, may lead to less effective access or could complicate the cleaning process due to potential angled obstructions within the line. Therefore, adhering to the requirement of placing cleanouts at right angles enhances both the functionality and efficiency of the plumbing system.