What must the officer do upon being notified of a burst main?

When an officer is notified of a burst main, the most appropriate action is to notify the dispatcher and battalion chief. This response is critical as it initiates the necessary coordination of resources and personnel to address the situation effectively. By informing the dispatcher, the officer ensures that other emergency response units can be aware of the issue and potentially assist if needed. Additionally, notifying the battalion chief allows for a higher level of command to assess the situation and deploy resources as necessary, ensuring a systematic and organized response to the emergency.

The other options, while they may seem relevant, do not embody the immediate and crucial communication that is needed in this scenario. Evacuating the area or conducting a water pressure test can be secondary actions that may need to occur after the initial assessment and coordination, and waiting for further instructions can unnecessarily delay response efforts during an urgent situation. Thus, timely communication with the dispatcher and battalion chief is paramount in effectively managing the incident.