In the Slovak Republic the ground water is one of the most important sources of water that is utilized for the drinking purposes. The natural ground water sources amount to 147 m3.s-1 out of which 75,7 m3.s-1 is exploitable resources. Important ground water resources are connected with the quaternary sediments (54 %) in a form of gravels and sands located in the Southwest of Slovakia - region Žitný ostrov (30 %), and the limestone dolomite complex of the Western Carpathian Mountains (25 %). At present only 20 % of the exploitable water amount is being utilized for the water supply. Ground water is predominantly used in a public water system for the drinking purposes (84,5 %), whereby the surface water accounts only for 15.5 %. The largest portion of groundwater consumption (almost 100 %) is devolved to the city of Bratislava and the western region of Slovakia. Our contribution focuses also on the need of qualitative and quantitative protection of groundwater.