CSLB Class B General Contractor's License Practice Exam

In plumbing systems, what is the risk of using incompatible materials?

1. Increased installation cost

2. Reduced water pressure

3. Higher likelihood of leaks

4. Increased maintenance requirements

The correct answer is: Higher likelihood of leaks

Using incompatible materials in plumbing systems significantly raises the likelihood of leaks. When different materials are joined, they may have varying expansion rates, chemical reactions, and physical properties. These discrepancies can lead to weak joints and connections. For instance, if two dissimilar metals are connected, galvanic corrosion could occur, which weakens the integrity of the joints over time. Additionally, the sealing methods used may not adequately accommodate the differing characteristics of the materials, further increasing the potential for water leakage. In terms of the other options, while using incompatible materials could potentially lead to increased installation costs due to the need for special fittings or adapters, this is not as direct a consequence as the risk of leaks. Reduced water pressure may occur in cases of obstruction or damage, but it is not inherently tied to the compatibility of materials. Increased maintenance requirements might result from leaks or system inefficiencies, but again, the primary and most immediate concern with incompatible materials is the heightened risk of water leaks.