Which of the following guidelines pertains to the installation of a drinking fountain?

The guideline that states a drinking fountain must be connected to a potable water supply only is essential for ensuring the safety and health of individuals using the fountain. Potable water is safe for human consumption, which is critical for drinking fountains as they provide water directly to people. By requiring that drinking fountains are connected only to a potable water supply, the plumbing code effectively prevents contamination from non-potable sources, which could pose serious health risks.

This guideline supports public health initiatives and maintains safe hydration practices. It ensures that everyone can trust the water they are consuming from the drinking fountain, thus promoting the safe use of drinking fountains in both public and private spaces.

Other options do not align with the critical standards of ensuring safe drinking water. For instance, a drinking fountain cannot be installed without a waste line since proper drainage is necessary to manage overflow and prevent water accumulation, which could lead to hygiene issues. Having a drain outlet is a requirement to efficiently remove excess water and maintain cleanliness. Additionally, drinking fountains can be installed in various settings, not just commercial buildings, ensuring access in schools, parks, and residential areas as well.