Identify the minimum depth for an underground service pipe.

• A. 500mm
• B. 750mm
• C. 1000mm
• D. 600mm

Answer: (B)

The main idea here is protecting an underground service pipe from freezing and accidental damage by burying it deep enough. In many plumbing codes, a minimum depth of 750 mm below ground level is required to keep the service line safe from frost and surface disturbances. This depth provides a reliable frost barrier in typical climates and helps prevent service interruptions if the surface is later disturbed by gardening, or if the pipe encounters minor digging. Deeper depths are only needed in areas with deeper frost lines or where there’s heavier traffic or road widening, but for a standard minimum, 750 mm is the standard target. Shallow depths like 500 mm or 600 mm don’t meet that frost protection requirement, while 1000 mm goes beyond the minimum and isn’t usually necessary unless specific conditions demand it.