If you bench the water service, the ws at all points must be ____ above the sewer.

If you bench the water service, the ws at all points must be ____ above the sewer.

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

Answer: (A)

When two lines share the same trench, keeping a vertical separation protects the potable water supply from sewer issues. The water service must sit at least 18 inches above the sewer at every point. This minimum gap helps prevent sewer gases or contaminants from reaching the water line, and it also provides room for proper bedding, backfilling, and maintenance access. Distances smaller than this compromise safety, while larger distances are not necessary for the standard practice, though they would still satisfy the requirement.

When two lines share the same trench, keeping a vertical separation protects the potable water supply from sewer issues. The water service must sit at least 18 inches above the sewer at every point. This minimum gap helps prevent sewer gases or contaminants from reaching the water line, and it also provides room for proper bedding, backfilling, and maintenance access. Distances smaller than this compromise safety, while larger distances are not necessary for the standard practice, though they would still satisfy the requirement.