Hot and cold water lines must be marked in what manner?

Hot and cold water lines must be marked in a specific color-coding system to ensure safety and prevent confusion during plumbing installation and maintenance. The standard practice is to use red to indicate hot water lines and blue for cold water lines. This color-coding helps anyone working with or around plumbing systems quickly identify the type of water being transported through the pipes, which is particularly important to prevent burns from hot water or to ensure proper connections in systems.

The colors used—red for hot and blue for cold—are widely adopted and recognized in plumbing codes and practices, aligning with both safety regulations and industry standards. This consistency in color helps mitigate the risk of accidents and allows for easier troubleshooting and repairs by making it clear which lines serve which function.

Other combinations, such as using green, yellow, or other colors, do not represent the standard and could potentially lead to confusion and unsafe situations. Thus, the correct marking system reinforces both safety protocols and best practices in plumbing installations.