Final answer:
A manometer is typically used to indicate the operation of a residential mitigation system utilizing ACTIVE soil depressurization.
Step-by-step explanation:
The most typically used device on a residential mitigation system utilizing ACTIVE soil depressurization to indicate the system is operating is a manometer.
A manometer is a device that measures the pressure difference between the soil beneath the house and the outside air. It is connected to the radon exhaust pipe and displays the pressure readings, showing that the system is actively depressurizing the soil and preventing the entry of radon gas into the home.