The present and potential saltwater contaminations of the quaternary and tertiary aquifers of the coastal areas of Caravelas and Alcobaca countries. Bahia, were studied through the analysis of 29 vertical electrical soundings, two geological logs and one electrical log of wells drilled in the region. The uppermain aquifer constitutes a complex aquifer composed of marine sands interbedded with clays and marls, and containing an extensive saltwater body being invaded by sea water. The lower and most important aquifer of the region, the Caravelas limestone, dips toward the east and is found in the area from the depth range of 25 to 40 m up to about 600 m. It is confined by shale layers and, as indicated by the electrical log of a well drilled near the shore, it is saturated with fresh water up to the depth of 375 m. As the Caravelas aquifer does not outcrop in the area, a lateral hydraulic conection with the Barreiras Group is suggested as the recharging mechanism to the groundwater system. The spacial configuration of the systems with a saltwater body above the Caravelas limestone as shown from the vertical electrical soundings calls for considerable caution in groundwater exploration in this area. Controled well pumping tests of the Caravelas aquifer to quantify its hydraulic parameters and also to measure the effective leakage between the two systems became an important. necessity for optimum utilization of this groundwater reserve.The present and potential saltwater contaminations of the quaternary and tertiary aquifers of the coastal areas of Caravelas and Alcobaca countries. Bahia, were studied through the analysis of 29 vertical electrical soundings, two geological logs and one electrical log of wells drilled in the region. The uppermain aquifer constitutes a complex aquifer composed of marine sands interbedded with clays and marls, and containing an extensive saltwater body being invaded by sea water. The lower and most important aquifer of the region, the Caravelas limestone, dips toward the east and is found in the area from the depth range of 25 to 40 m up to about 600 m. It is confined by shale layers and, as indicated by the electrical log of a well drilled near the shore, it is saturated with fresh water up to the depth of 375 m. As the Caravelas aquifer does not outcrop in the area, a lateral hydraulic conection with the Barreiras Group is suggested as the recharging mechanism to the groundwater system. The spacial configuration of the systems with a saltwater body above the Caravelas limestone as shown from the vertical electrical soundings calls for considerable caution in groundwater exploration in this area. Controled well pumping tests of the Caravelas aquifer to quantify its hydraulic parameters and also to measure the effective leakage between the two systems became an important. necessity for optimum utilization of this groundwater reserve.