In order to present the fundamental data for revealing the action mechanism of water exposed to the electric field, the physical properties of the water and the ion concentration in the water were measured. The half width of ^<17>O-NMR spectrum, pH, and the electric conductivity was changed after charcoal was soaked in the distilled water for 6 h. Applying the electric field, pH of the distilled water and the tap water was moved near the neutrality. The half width of ^<17>O-NMR spectrum depended on pH regardless of the experimental condition. Consequently it is not adequate to use the width as an index of the cluster size of water.