In gravity sewer line installation using a solid coupling pipe, on which end should the coupling be attached?

In gravity sewer line installation using a solid coupling pipe, on which end should the coupling be attached?

• A. Downstream end
• B. Upstream end
• C. Middle of the line
• D. Anywhere along the run

Answer: (B)

In a gravity sewer system, flow goes from upstream to downstream, so the joint should be oriented toward the source of the flow. Attaching the solid coupling at the upstream end allows the downstream pipe to slide into a cemented, properly seated end, producing a clean, tight seal as the wastewater continues toward the downstream section. This setup helps ensure the joint is formed under flow conditions in the correct direction and reduces the chance of solids catching at the joint or the joint not seating fully. Putting the coupling on the downstream end or in the middle of the run misplaces the joint relative to the flow, increasing the risk of misalignment, blockage, or leaks.

In a gravity sewer system, flow goes from upstream to downstream, so the joint should be oriented toward the source of the flow. Attaching the solid coupling at the upstream end allows the downstream pipe to slide into a cemented, properly seated end, producing a clean, tight seal as the wastewater continues toward the downstream section. This setup helps ensure the joint is formed under flow conditions in the correct direction and reduces the chance of solids catching at the joint or the joint not seating fully. Putting the coupling on the downstream end or in the middle of the run misplaces the joint relative to the flow, increasing the risk of misalignment, blockage, or leaks.