Utility employees should protect the water supply from which of the following?

Utility employees should be primarily focused on protecting the water supply from contamination, as this is a critical aspect of maintaining public health and ensuring safe drinking water. Contamination can occur from various sources, such as chemical spills, improper waste disposal, or unapproved substances entering the water supply. If contamination occurs, it can lead to serious health risks for the community relying on that water source.

While public tours can be a concern in terms of potential access to sensitive areas or equipment, the foremost duty of utility employees is the proactive and continuous safeguarding of the water against any form of contamination. Therefore, the emphasis is placed strictly on contamination as the essential concern.

Addressing public tours and employee errors, while relevant to overall operations and safety measures, does not directly influence the fundamental goal of protecting the water quality and supply. The choice that highlights only contamination reflects the priority and critical importance of safeguarding water resources from harmful substances.