The percolation pressure through the porous gas diffusion layer (GDL) is known to depend on the pore size and geometry, as well as the wetting conditions within the material. It is less clear how the water-gas transport changes with the use of different materials and under varied fuel cell operating conditions. A major reason of discrepancy between models and experimental results is an inaccurate description of the interfacial behavior. Elementary simulations that capture the interface evolution as water breaks through a pore indicate that the process is more sensitive to mixed wetting conditions than to the geometry itself. The proposed model accounts for mixed wetting conditions by allowing for contact line slippage on non wetting surfaces while on wetting surfaces the contact line is pinned. The breakthrough pressure is found to be approximately 40% larger for the mixed wetting pore versus the wetting counterpart. Existing GDL experimental studies seem to indicate a change in the breakthrough pressure in the same ratio when surface wetting modifications are made which effectively create mixed-wetting pores.