Which requirement determines the safety of water used in plumbing?

The requirement that determines the safety of water used in plumbing is primarily based on the piping material used. The choice of piping materials can significantly impact water safety, as certain materials can leach harmful substances into the water supply or may be susceptible to corrosion or contamination. Using approved and safe plumbing materials ensures that the water remains uncontaminated, meets health standards, and does not pose a risk to human health.

While color coding, warning labels, and pressure limits are relevant for identifying and managing plumbing systems, they do not directly ensure the safety of the water itself. Color coding helps in recognizing various types of pipes and their intended uses, warning labels provide important safety information, and pressure limits are crucial for preventing leaks and bursts in plumbing systems. However, these aspects do not directly affect the quality or safety of the water being transported. Thus, the choice of piping material is the fundamental requirement that guarantees the safety of water in plumbing systems.