The population of northern coastal area of Rio de Janeiro State (Brazil) relies on coastal groundwater resources as its main source of water supply. However, the increasing demand for groundwater resources in the last decade has increased the risk of aquifers’ overexploitation and salinization.The Emborê Formation, which is part of the Campos sedimentary basin, is indeed the most important aquifer in Rio de Janeiro Stat and the main source of fresh water resources for a region, which includes the municipalities of Campos dos Goytacazes, São Francisco de Itabapoana, São João da Barra and Quissamã.