Adsorption equilibria for solvent dehydration, namely, removal of trace water from solvents by inorganic adsorbents such as silica gels and activated alumina, were measured for various combinations of solvents and adsorbents to test the applicability of the capillary phase separation concept to these systems. The concept is that a component in solution with limited mutual solubility can be separated out into narrow pores even at a concentration less than the saturated concentration, by a capillary effect similar to capillary condensation. The results show definite existence of capillary phase separation in these systems, and verify the applicability of the isotherm estimation method proposed earlier by the authors for adsorption of organic solutes from aqueous solution.