This paper deals with the relationship between the physical characteristics of the Rharb-Mamora basin (Northern Morocco) and the distribution of hydraulic conductivity values in the Plio-Quaternary aquifer. A steady state groundwater model has been calibrated using these values. The distribution of hydraulic conductivity corresponds to a hydrodynamic partition with permeabilities of 2×10−3 to 5×10−2 ms−1 (in the coastal part). A numerical modeling process shows a relative error map between calculated and measured piezometric surfaces, in order to facilitate calibration in steady state. The distribution of hydraulic conductivity values, and the lateral variation of sequences (deduced from engineering geology methods e.g. hydrogeological drilling data, seismic reflection interpretation, and geostatistical analysis), are controlled by synsedimentary fault activity, which deepened the Mio-Pliocene basement resulting in a thickening of overlying permeable rocks.