The carbonate aquifers of the Lower Andarax is a significant geothermal anomaly, as evidenced by the high temperature of the spring waters (22 - 40 °C). The most saline waters (2000 - 3000 mg.L1) correspond to the Deep Aquifer, which presents a sodium chloride sulphate facies, while the least saline (500 mg.L'1), with a magnesium calcite bicarbonate type, are found in some sectors of the Carbonate Aquifer. The sectors of the Carbonate Aquifer having less saline waters and which are directly associated with more rapid flows can thus be identified. In the Deep Aquifer, the situation is more complex, as the intense thermal anomaly of the are a acts in conjunction with the influence of evaporitic materials and a long residence time of the groundwater, factors which tend to produce the high concentrations of boron and lithium