What is the required separation distance between water service pipe and the building sewer?

• A. 3 Feet
• B. 5 Feet
• C. 7 Feet
• D. 10 Feet

Answer: (B)

Keeping potable water lines separate from the building sewer is about preventing cross‑connection and backflow contamination. The standard rule is to maintain five feet of horizontal distance between the water service pipe and the building sewer. This gap reduces the chance that sewer leaks or pressure changes could push contaminants into the drinking-water line, and it supports safer maintenance and installation of backflow protection if needed. If the lines must cross, typically you keep the water line above the sewer line and follow local codes for additional protections. So, five feet is the correct separation.