Which action is taken after setting up the ground monitor and before calling for water?

Setting up the ground monitor involves multiple critical steps to ensure its safe and effective operation. The correct action to take after setting up the monitor, and before calling for water, is for the firefighter to prepare the monitor for operation. This preparation can include adjusting the monitor's angle, making sure connections are secure, and ensuring that any necessary controls are properly set.

This step is crucial because it ensures that the equipment is operational and will function as intended when water is called for. If the monitor is not properly prepared, it may lead to ineffective water delivery or even equipment failure when under pressure.

While checking the water supply, signaling the team, and securing the area are also important considerations in the sequence of operations, they occur either before the setup of the monitor or as a part of the overall operational readiness. However, preparing the monitor specifically addresses the immediate readiness of the equipment itself, making it a necessary step in the process.