Preliminary results on a technique of Electrochemical-Impedance Spectroscopy (EIS) applied to the characterization of diffusion and absorption properties of water in an epoxy resin are reported. Thin films of polymer adhering to aluminum constitute simulated adhesive bonds. Immersion in water and assessment via electro-chemical impedance measurements allowed estimation of diffusion rates and water uptake. In parallel, classic gravimetric experiments were undertaken on thin, free films of the same polymer. Results of the two techniques are acceptably comparable, and thus EIS could be developed as a new tool for in situ assessment of adhesives.