A system, method and device may be used to monitor fluid levels in a drill pipe in borehole. The system includes an electromagnetic (EM) generator to generate a traveling wave of electromagnetic energy to propagate along a linear path through the drill pipe towards a surface of the fluid, a detector to detect a portion of the electromagnetic wave reflected from the surface of the fluid and propagated through the drill pipe towards the detector, a processor to analyze detected signals to determine a level of the surface of the fluid. In an embodiment, the system includes a pump controller to control the operation of a pump located in the wellbore or at the mudline based on the fluid surface level.