When benching the water service, the required vertical clearance above the sewer is 18 inches.

When benching the water service, the required vertical clearance above the sewer is 18 inches.

• A. 12 Inches
• B. 18 Inches
• C. 24 Inches
• D. 36 Inches

Answer: (B)

When you bench a trench where the water service sits above a sewer, you need a vertical separation between the two pipes to protect both and keep the trench manageable. The required spacing is 18 inches, which provides enough room for proper bedding and backfilling of the water service without crowding the sewer, while also allowing room to work and inspect. This clearance helps prevent damage to either pipe during installation and future maintenance, and reduces the risk of backfill material or soil movement affecting the water line. Clearances smaller than 18 inches would be too tight and risky, while larger clearances aren’t necessary for typical benching and would complicate trenching unnecessarily.

When you bench a trench where the water service sits above a sewer, you need a vertical separation between the two pipes to protect both and keep the trench manageable. The required spacing is 18 inches, which provides enough room for proper bedding and backfilling of the water service without crowding the sewer, while also allowing room to work and inspect. This clearance helps prevent damage to either pipe during installation and future maintenance, and reduces the risk of backfill material or soil movement affecting the water line. Clearances smaller than 18 inches would be too tight and risky, while larger clearances aren’t necessary for typical benching and would complicate trenching unnecessarily.