Numerical solutions of the flow equation for the drying of porous media have been obtained assuming an exponential relationship between diffusivity and water content. Solutions are presented for both semi‐infinite and finite media for isothermal conditions, when gravity is absent or negligible. The rate of drying of laboratory soil columns is in good agreement with the numerical solutions. The rate of drying is controlled largely by the boundary conditions and physical characteristics of the soil that determine the rate of movement of water in the soil in the liquid phase.