Analysis of the admittance of quartz resonator in contact with water has shown that the viscosity-density product of water at a metallic electrode surface decreases during the positive potential scan. This decrease is more pronounced when the electrode surface is coated by a thin layer of polymer. Literature data provide evidence that the density of water in the first layer attached to the surface increases when the potential is shifted into the positive direction. It is concluded that during such potential scan the decrease of viscosity is larger than the increase of density. (c) 2006 Elsevier Ltd. All rights reserved.