Plumbing Level 2 – Cold Water Systems Practice Test

Pipes are color‑coded so you can tell at a glance what they carry. Cold potable water lines are typically blue, so the incoming cold water main is identified by blue. This color cue helps prevent mixing with hot water (usually red) or with non‑potable lines. Green is often used for non‑potable or irrigation systems in some codes, and black is not a standard marker for a cold potable main. Always follow the local code, but blue is the common indicator for cold water.