96 % of surface water resources are of foreign origin. Major rivers are Danube, Tisza and Drava, while Lake Balaton with its 605 sq km surface area is the largest lake in Central Europe. With around 25% of the country comprising floodplains, flooding is a key issue.
The yearly average precipitation is 600 mm with uneven area distribution. In addition, the ratio of potential evaporation and precipitation may amount to 1.5 in the south-east corner of the country. That increases the probability of the occurrence of droughts which generally occur every 3-5 years.
Hungary’s geothermal features are rather favourable. On about 80 per cent of the territory, thermal water of a temperature higher than 30 degrees Celsius can be exploited. The water supply decisively relies on groundwater.