A synthesis of work carried out for several years within our laboratory is presented. The first part includes an experimental study. The tests are performed on hollow cylindrical concrete specimens, subjected to compressive loading. At stress levels lower than 80 % of the peak stress, the variation of permeability is small and it is slightly influenced by the stress, but as the load exceeds 80 % of the peak stress, micro-cracking increases rapidly, causing an increase of the permeability and a greater sensitivity to the applied load. In the post-peak phase the increase of permeability is much larger due to significant crack width growth. The effects of the applied load on permeability are greater with temperature. Finally, the experimental results seem to agree with the format of coupled evolution of the permeability due to damage and temperature assumed by Gawin et al. [10]. The second part of this paper includes a numerical study. The lattice mechanics model is extended to the hydraulic problem and, for this case, it appears that permeability is the size independent variable. Additionally, the evolution of permeability with damage and with stress ratio in the pre-peak phase is compared with experimental results on different types of concrete.