Where should you block off the manhole to repair a broken sewer main?

Blocking off the outlet side of the manhole to repair a broken sewer main is crucial for several reasons. First, the outlet side typically directs flow away from the manhole and into the sewer system. By blocking this side, maintenance crews can prevent any wastewater from flowing back into the area where repairs are being made, thereby minimizing the risk of overflow or spill incidents during the repair process.

Additionally, securing the outlet side ensures that any potential wastewater remaining in the sewer line does not interfere with the repair operations, allowing workers to complete their tasks safely and efficiently. Making this choice maintains a controlled environment, which is vital for proper maintenance protocols and safety standards in wastewater management.

Other options may not provide the necessary control over water flow required to perform repairs effectively or could lead to complications during the maintenance process. Blocking off the inlet or gravity sides could lead to safety risks due to backflow, while the pressure side is not typically relevant in the context of a gravity-based sewer system. Properly managing the outlet side is essential for successful and safe sewer main repairs.