Master Plumber Practice Exam 2025 – Complete Prep Guide

Copper is generally discouraged for underground plumbing applications due to its susceptibility to corrosion when buried in soil, especially in environments with high acidity or saline conditions. While copper is an excellent plumbing material for above-ground applications due to its durability and antimicrobial properties, its long-term performance in underground settings can be compromised, leading to leaks and potential failures.

On the other hand, materials like PVC, cast iron, and ABS are favored for underground plumbing because they offer greater resistance to the elements and corrosion. PVC is widely used for its lightweight nature, chemical resistance, and ease of installation. Cast iron, known for its robustness, is often used for sewer lines, while ABS is popular in drainage and waste applications due to its strength and impact resistance. Each of these materials has specific properties that make them suitable for underground use, whereas copper is typically avoided in such scenarios.