Water permeability is one of the most important functional characteristics of the geotextiles, being mandatorily marked in the factsheets of any type of trademark geotextile. This feature is found in the standards under the denomination of "Ge-Ye-Flow K". The Mathematical modeling of the water permeability of geotextiles examines the influence of the technological parameter's quality. Using the 3D and 2D graphics, it may achieve this purpose. In this paper it is considered that the technological parameters - interweaving density and depth of penetration - are independent variables which have a huge influence on the quality of the analyzed geotextiles