The aim of the present study is to improve the knowledge of the geometry and hydrogeology of the eastern Haouz aquifer and part of the Upper Tassaout aquifer, using the analysis and interpretation of boreholes, gravimetric analysis, seismic reflection and piezometric data. The examination of the gravity data shows that the Bouguer anomaly map is affected by a regional gradient increasing from the southeast to northwest. This gradient was determined and subtracted from the original data, to provide a residual gravity map which shows clearly highlighted anomalies. These anomalies generally reflect outcrop areas of the basement and the variation in thickness of the sedimentary cover across the study area. The seismic reflection profile confirms the gravity results, and shows that the region is formed by a horst which corresponds to the exposed bedrock of Jebilets in the north of Haouz basin, and a subsidence area where coverage is widespread in the south of the plain of Haouz. In this area, the large thickness of the cover allows the accumulation of water and provides the recharge of the groundwater reservoir. The rise of the basement in the north of the Haouz basin imposes a dividing line of two groundwater flow direction.