What should be checked regularly to ensure a pumper's operational readiness?

Regularly checking fuel levels is crucial for ensuring a pumper's operational readiness because a pumper must have an adequate supply of fuel to maintain its ability to operate effectively. Without sufficient fuel, the pumper cannot function, which could compromise emergency response efforts. Monitoring fuel levels allows for timely refueling and ensures that the unit is always ready for immediate deployment when needed.

While other factors such as water source temperature, weather conditions, and nearby traffic may play important roles in the overall operation and safety during a response, they do not directly impact the pumper's ability to function in the absence of fuel. Fuel levels take precedence in this scenario, as they directly affect the equipment's operational capability.