The southern part of the Rharb basin is represented by the Mamora basin. Thanks to its hydraulic potentialities, the Mamora groundwater supplies not only Rabat (the capital) and Kenitra cities, but also the economic city of Morocco: Casablanca, as well as industrial and agricultural sectors. Along with this heavy sollicitation, and like other basins belonging to the Atlantic margin of Morocco such as the Essaouira Basin (Laftouhi et al. 2003; Mennan et al., 2001), the Doukkala Basin (El Achheb, 2000) and the plain of Souss (Hsissou et al., 1999), the declining groundwater levels and rainfall fluctuations expose the water to salt pollution. This work aims to monitor the spatial quality of hydrochemical groundwater and to understand the process of the mineralization in according to the saltwater intrusion, the hydraulic gradient and the water-aquifer interaction. Hydrochemical correlations which are realized in the coastal area showed contamination by seawater. The analysis and the interpretation wells highlights benches salt which may explain the mineralization of water in the zone far from the cost. The seawater intrusion and the identification of the Pre-Rifean complex were identified by the electrical and seismic methods. Key words: hydrochemical evolution, saltwater, correlation, interaction, geophysics