Which statement about deflection testing is true?

• A. It is optional for all pipe
• B. It is required only for diameters over 36 inches
• C. It must be performed on all pipe
• D. It is prohibited

Answer: (C)

Deflection testing checks how much a buried pipe has bent under the load of backfill and surrounding conditions. The goal is to ensure the pipe stays within the allowable deformation so joints remain watertight and the line maintains integrity under service loading. Because even small pipes can settle or shift and cause problems if deflection is excessive, most standards require testing on every pipe installation, not just large diameters. This isn’t optional, and it isn’t restricted to pipes above a certain size or prohibited in any way. If deflection is beyond the allowed limit, corrective actions—like adjusting backfill, recompactment, or replacing a section—are needed to restore performance.