Abstract The behavior of different reverse osmosis membranes, namely, HR98PP, SEPA‐MS05, and DESAL‐3B, was compared with the one predicted by a solution‐diffusion model. This model assumes that the membrane has a homogeneous, nonporous surface layer and uses two main parameters, permeate concentration C p and volumetric permeate flux Q p , to characterize the membrane system. In order to calculate these parameters, the theoretical values of water and solute permeability constants, A w and B s , and the osmotic pressure coefficient, Ψ, were initially determined. Using the software Sigma Plot V 10.0, accurate values of Ψ, Q p , and C p were only obtained for the DESAL‐3B membrane, i.e., the selected solution‐diffusion model can be applied to this membrane.