What should a lifeguard always maintain while on duty?

A lifeguard should always maintain a constant scan of the water and surrounding area while on duty because this is essential for ensuring the safety of all patrons. By continuously monitoring the environment, lifeguards are able to quickly identify potential hazards, recognize swimmers who may be in distress, and respond promptly to any emergencies. The effectiveness of a lifeguard's response in critical situations is significantly increased when they are consistently vigilant and aware of the activities happening within their designated area.

In contrast, other options may involve important aspects of lifeguarding but do not hold the same level of urgency. A clear plan for managing patrons is beneficial; however, without the constant observation of the water, a lifeguard cannot effectively implement that plan. Focusing solely on swimmers in a designated area limits the lifeguard’s awareness of the broader environment where other patrons may also require assistance. While a full schedule of facility activities helps in planning and operations, it does not contribute directly to the immediate surveillance and safety responsibilities crucial to a lifeguard's role.