In this study, 92 groundwater samples were collected from the Attica region (Greece). Moreover, geographical information system database, geochemistry of groundwater samples and statistics were applied. These were used for studying the chemical parameters (NO3-, Mg2+, Ca2+, Cl-, and Na+) and conductivity spatial distribution and for assessing their environmental impact. The ranges of chemical parameters of the water samples (in mg L-1) are: NO3- 1-306, Mg2+ 2-293, Ca2+ 3-453, Cl- 5-1,988, and Na+ 4-475. The elevated concentrations of sodium, Mg2+, Cl- are attributed to natural contamination (seawater intrusion). On the other hand, NO3- elevated concentrations are attributed to anthropogenic contamination (nitrate fertilizers). The results of the GIS analysis showed that elevated values of Na+, Mg2+, Cl- are related to shrubby and sparsely vegetated areas, while elevated values of NO3- are connected with urban and agricultural areas.