This type of pipe is no longer installed in the US.

• A. PVC pipe
• B. Gray cast-iron pipe
• C. Ductile iron pipe
• D. Plastic-lined steel pipe

Answer: (B)

The key idea is how pipe materials have evolved in the water system to balance strength, durability, and ease of installation. Gray cast-iron pipe is brittle and relatively heavy, and it tends to corrode and tuberculate over time. It also doesn’t handle ground movement or high pressures as well as newer materials. Because of these limitations, utilities shifted to stronger, more reliable options such as ductile iron and modern plastics for new main installations. So, while you might still encounter old gray cast-iron pipes in aging networks, they’re no longer installed for new water mains.

PVC and ductile iron are common today due to corrosion resistance, strength, and easier handling, and plastic-lined steel has niche uses but isn’t the standard for new mains.