Which statement correctly describes when backfilling should occur relative to inspection and testing of the piping?

• A. Backfill immediately after laying the pipe
• B. Backfill after pipe is laid but before inspection
• C. Backfill only after the piping has been inspected, tested and approved
• D. Backfill when trench has been dug

Answer: (C)

Backfilling is done only after the piping has been inspected, tested, and approved. This keeps defects from being hidden and makes sure joints, alignment, and bedding have been verified while access to the work is still available. If you backfill before testing, leaks or misalignments could be buried, requiring costly and time-consuming excavation to fix later. It also confirms that the trench conditions and support meet code before the pipe is buried, so settlement or damage from early backfill is less likely. In short, the safety and reliability of the system depend on completing inspection and testing prior to covering the pipe with soil.