There is very few ways to detect the amount of water inside polyvinyl chloride (PVC) pipes without physical intervention. In this study, using additive manufacturing technology, it has been tried to determine the filling rate of water in PVC water pipes with a 3D printed clamp. The fact that the dielectric of distilled water is approximately 80 times that of air has been decisive in the transmission of power from the inner medium of the PVC pipe. In this way, when the amount of water increases in the PVC pipe, the RF power transmission will be decrease depending on level of water inner side of the pipe. The clamp was designed in the f(0) = 2.45 GHz ISM band. LC impedance matching was applied to the two ports of the clamp. Thus, higher transmission coefficient was obtained. Used as a near field probe, the clamp was designed to be used horizontally anywhere on the pipe, pluggable. Input power from first port of the clamp is sent to the spectrum analyzer through its second port. The measurement and simulation results show that the transmission coefficient between the ports varies between -9 dB and -15 dB according to the selected fill percentages of the pipe.