In situ lysimetric columns are here used to study the over-all functioning and pedogenesis of a constructed soil, resulting from the deliberate combination of various anthropic materials. Our work focused on the evolution of the water distribution inside the soil as an indicator of the evolution of the soil structure. Significant results were obtained highlighting the fact that constructed Technosols are structuring by global compaction and change of the porosity distribution involving drastic changes in hydrodynamic. This evolution is fast and intense which can be considered as an original characteristic of Technosols' pedogenesis.