Recently, computational fluid dynamics (CFD) models of flows in membrane channels have been proposed and validated against published simplified models available in the literature. In this paper, experimental and numerical analysis is performed for a reverse osmosis (RO) module and results compared in order to provide further validation of the model from a practical prospective. Our results show that, in order to improve the accuracy of the calculations at high pressure, a membrane permeability that varies with the operational pressure must be taken into account.