The study of aquifers of the Lece andesite complex (LAC) and its surroundings yielded a new procedural stepwise analysis that allowed the assessment of the origin of elements, particularly in areas affected by both anthropogenic and natural influences. The methodology uses the mineralogical composition of the rocks, including the elements available in rocks and groundwater. This study analyzes the element ratios B/Cl⁻, Na⁺/Ca²⁺, Ca^2+/Mg²⁺, HCO₃⁻/Cl⁻, and Na⁺/Na⁺ + Cl⁻; the correlations are coupled with a statistical analysis. In addition to reevaluating the already published water content, we provide an important new dataset. The results show that the main source of the water contamination with the elements B, F, U, As, Cu, Fe, Zn, Co, and Ni is the processes occurring at the contact between the groundwaters and non-altered/altered (propylitized) andesite rocks. This is also observed in the waters extracted from crystalline schists. The results may help develop an efficient use and assessment of the qualitative water potential of the LAC reservoirs. Similarly, the results highlight the applicability of the groundwaters, facilitating their regional research and use, further encouraging new initiatives for the preservation and protection of human and animal health.