In a disposal field drain installation, if the invert of the inlet is placed 1 inch above the outlets, you have proceeded:

In a disposal field drain installation, if the invert of the inlet is placed 1 inch above the outlets, you have proceeded:

• A. Correctly
• B. Incorrectly
• C. Partially
• D. Not specified

Answer: (A)

In a disposal field drain, gravity flow is achieved by making the pipe slope downward from the point of entry toward the field outlets. Placing the inlet invert 1 inch above the outlet invert creates a positive fall along the flow path, so effluent will naturally move toward the outlets without needing a pump. That small vertical differential is enough to establish the necessary grade for gravity drainage, prevent pooling, and avoid backflow. If the inlet were not higher than the outlets, flow could stagnate or back up, defeating the purpose of the disposal field. So this arrangement is correct.

In a disposal field drain, gravity flow is achieved by making the pipe slope downward from the point of entry toward the field outlets. Placing the inlet invert 1 inch above the outlet invert creates a positive fall along the flow path, so effluent will naturally move toward the outlets without needing a pump. That small vertical differential is enough to establish the necessary grade for gravity drainage, prevent pooling, and avoid backflow. If the inlet were not higher than the outlets, flow could stagnate or back up, defeating the purpose of the disposal field. So this arrangement is correct.