The present disclosure provides a fluid monitoring device comprising a transmitter housing attached to an underside of a cap, configured to accept a cable and comprising alignment features that index the housing to the cap. The device includes a printed circuit board (PCB) within the transmitter housing, comprising a battery, microprocessor, and transmitter for wireless communication with peripheral devices. The device also comprises a linkage and sensor assembly with a capacitive sensor, wherein the linkage tethers the sensor assembly to the transmitter housing via the cable. The microprocessor interprets capacitance readings from the capacitive sensor and, upon detecting readings above a threshold, instructs the transmitter to transmit a flood signal.