The total length of rivers and canals reaches the length of 44,943 km. The largest river is the Danube and the longest is the Vah (367.2 km).

Water spring potential is about 400 m3/sec., however the total water flow is around 3,300 m3/sec. The bulk of surface water flows from neighboring countries - Austria, Czech Republic and Ukraine, and only a small part rises in Slovakia (14%).

Slovak Water Management Enterprise is managing majority of surface water courses in the length of 29,338 km. It has regional branches in four river basins of the Danube, Vah, Hron and Bodrog rivers covering 49,015 km2.

Forestry organizations take care of small water courses administration and maintenance in the length of 18,079 km.

There are 54 large dams with a total volume of 1,890 million m3 of water. Out of them, seven are used to supply drinking water.

Groundwater resources in the volume of 146.7 m3 / s are unequally distributed due to geological conditions and only 51.7% are usable. The most important region with regards to groundwater resources is Podunajská Lowlands (56%).