An accurate low order model (mean value model) that captures main water transport mechanisms through the components of a PEM fuel cell was developed. Fast simulation time was achieved through a lumped approach in modeling the space-dependent phenomena. Evaporation and capillarity were assumed to be the predominant mechanisms of water flow through the gas diffusion media. The innovative features of the model are not only to simulate the water transport inside the porous media with relative simplicity, but also to simulate the water transport at the interface between the gas diffusion layer and gas flow channel. In order to preserve a light computational burden, the complex air flow-droplet interaction was modeled with several simplifying assumptions, and with the support of measured data. The physics that characterizes the single droplet-air flow interaction was analyzed with an experimental apparatus constructed to study the droplet growth and detachment process. Furthermore, the experimental findings were exploited to feed the numerical model with the missing theoretical information, and empirical submodels to guarantee accuracy. Thanks to the followed fast computational time of the mean value approach, the model is suitable for fuel cell design and optimization, as well as diagnosis and control strategies development studies.