Illinois Plumbing Code Practice Exam 2025 - Free Plumbing Code Practice Questions and Study Guide

The correct answer is C because the Illinois Plumbing Code emphasizes the importance of protecting water service pipes from freezing temperatures. When pipes are installed outside of a building or in an exterior wall, they are exposed to environmental conditions that can lead to freezing during cold weather. If the water inside the pipes freezes, it can cause the pipes to burst, leading to significant damage and costly repairs. Therefore, appropriate measures must be taken to insulate or otherwise protect these pipes to prevent freezing.

The other options, while potentially important in other contexts, do not pertain directly to this specific requirement of the Illinois Plumbing Code. Contaminants may concern the quality of the water, but they do not address the immediate risk of physical damage due to temperature. Dust might be a factor regarding cleanliness or maintenance but is not a critical issue for the integrity of the water delivery system. Leaks can be a concern for any plumbing installation but are not specifically tied to the location of the pipe or its environmental exposure.