The diffusion coefficient of water An associated with the ingress in an organic coating is an indicator of the rate at which the coating absorbs water. Likewise, the diffusion coefficient associated with water egress Dout is an indicator of the drying rate of the coating. The measurement of D in by gravimetric and capacitance methods have been reported, and so to Dout by gravimetry. Reported recently was a method that employed a hydrophilic room temperature ionic liquid to monitor the capacitance changes associated with the egress of water from which Dout was calculated. Experimental results associated with cyclic dilute NaCl wetting and ionic liquid drying are presented for an epoxy coating on an AA 2024-T3 substrate. The Din and Dout values were calculated using a short-time approximate solution and a series solution to Fick's second law. Electrochemical impedance spectra associated with the ends of wet and dry stages of the cycles are presented. Copyright The Electrochemical Society.