What type of piping is typically used for underground building drains?

• A. PEX tubing
• B. Copper tubing
• C. DWV PVC Schedule 40
• D. ABS

Answer: (C)

Underground building drains need a pipe that is specifically designed to carry waste and stand up to long, buried runs. DWV PVC Schedule 40 fits this purpose perfectly because it is made for drainage systems (drain, waste, and vent), is rigid and strong for underground use, and uses dependable solvent-weld joints that resist leaks over time. The Schedule 40 wall thickness provides durability in soil conditions without making the pipe overly heavy to handle, and PVC resists corrosion from soil and wastewater.

Pex tubing and copper are typically used for water supply lines, not for sanitary drainage. ABS is another plastic used for drainage in some places, but DWV PVC Schedule 40 is the standard choice for underground drains in many codes due to its availability, ease of joining, and proven performance.