Abstract: A dual cell Electrochemical Impedance System (EIS) testing apparatus and method for measuring coating integrity on various substrates. The counter reference electrode is in a first cell in electrical contact with the coating. The working electrode is in a second cell in electrical contact with the coating instead of the substrate material acting as the working electrode. Voltage is applied at the working electrode at varying frequencies and current is measured at the combined reference/counter electrode. From the known voltage and the measured current, the impedance of the coating is calculated. Coatings on non-metallic substrates can be measured with this apparatus. In one embodiment, the EIS cells are in the form of vacuum cups containing an electrolyte gel for testing non-horizontal coatings in the field. Also, known current can be applied to the working electrode and voltage measured at the counter reference electrode can be used to calculate coating impedance.