The contribution describes a sensor system based on impedance spectroscopy that is intended to being used to permanently monitor the drinking water piping with regard to bacterial contamination. It consists of the main sensor containing a porous polyamide substrate trap serving as a trap for microorganisms, which can grow and build a biofilm, and a reference sensor. The process measuring and control unit enabled the comparison of the impedimetric signals of the measuring and reference channels as well as a difference signal output. The latter should trigger the antibacterial treatment of the water recirculation components, which prevents a health threat due to water contamination. In order to prevent the microbially influenced corrosion (MIC) of the electrode material, a biocompatible polymer coating was performed and its long-term stability was studied by means of the time-dependent impedimetric signal. The recorded Bode and Nyquist plots were fitted using an equivalent circuit model and the corresponding model parameters were obtained.