A fire hydrant water leak and theft detection system is connected to a dry barrel fire hydrant. The detector is connected to the upper barrel portion of the fire hydrant below the nozzle assembly and includes a pair of electrodes. A signal is generated when water in the upper barrel portion closes an electrical circuit between the two electrodes due to the conductivity of the water between the electrodes. The detection system sends a signal to a network system upon detection of water in the barrel portion and relays to remote monitoring locations.