Each outlet on a nonpotable water system used for special purposes must be posted with what cautionary message?

The appropriate cautionary message for each outlet on a nonpotable water system used for special purposes is "CAUTION-NONPOTABLE WATER DO NOT DRINK." This message is critical as it directly informs users that the water is not safe for consumption. Nonpotable water can contain contaminants or pathogens that render it unsafe for drinking, thus the importance of clear warning signage to prevent accidental ingestion.

This message serves as a vital reminder to both trained professionals and the general public and helps to reduce health risks associated with the misuse of nonpotable water outlets. Furthermore, the specificity of this cautionary statement aligns with public safety regulations and standards outlined in plumbing codes and health guidelines.

The other options do not adequately serve the purpose of communicating the specific hazard associated with nonpotable water. While "USE WITH CAUTION" implies the need for care, it lacks the direct warning regarding the safety of the water itself. "FOR INDUSTRIAL USE ONLY" implies limitations on the use of the water but does not address the health risks of consuming it. Lastly, "DO NOT DISPOSE OF TOXIC MATERIALS" is unrelated to drinking water safety and instead addresses waste disposal protocols. Thus, the chosen message effectively prioritizes public health and safety concerning non