A nozzle cap assembly includes a nozzle cap defining a bore, the bore defining internal threading configured to mount the nozzle cap on a nozzle of a fire hydrant; an enclosure attached to the nozzle cap; a vibration sensor positioned within the enclosure; a circuit board positioned within the enclosure, the circuit board connected in electrical communication with the vibration sensor, the circuit board configured to process an electrical current transmitted by the vibration sensor; and an antenna connected in electrical communication with the circuit board, the antenna configured to transmit a signal received from the circuit board.