In 2021 the Water Rights for special use of water were issued in 8385 acts (water permits, concessions), with additional more than 10.000 cases of minor spatial water uses with neglectable influence on state of water, were in the process of evidencing in the Water Book.

The total renewable amount of groundwater in shallow aquifers in Slovenia in the hydrological year 2019 was below the average of the comparative hydrological water balance period 1981-2010.

Water protection areas cover 3532 km² or 17,4% of Slovenia’s land surface in 2021. This is a slight increase, compared to 2017, but the goal of protecting the areas of all water sources for public water supply with a regulation on national level, has not been reached yet.

The Slovenian EHVZ database (Hydrography and Water Land Records) contains 67.549 watercourses with total length of 41.071 km. Total area of still waters is 24 km² and river reservoirs 31 km².

For use in water management, water land areas are delineated. Total area of water land in Slovenia is 387 km², which is 1, 9 % of continental area of the Republic of Slovenia. Marine water land area is 214 km².

Nutrients, especially nitrogen and phosphorus compounds, are important for the growth of algae and higher plants, but in high concentrations can cause undesirable changes in aquatic organisms and seawater quality. Long-term measurements of selected nutrients in the Slovenian sea show that their concentrations have decreased significantly. Therefore, the ecological status of the Slovenian Sea is assessed as good to very good based on nutrients in recent years.

Trends in annual precipitation are not as obvious as temperature trends. Changes between years and differences between regions are significant. According to climate change projections, annual precipitation will slightly increase while changes in seasonal precipitation will be noticeable. The most worrying are summer conditions, because less precipitation and higher temperature might result in higher frequency of droughts. In winter, more precipitation may lead to an increase in flooding events.

Precipitation is highly variable in space and time, even more than temperature (storms and hail). In the last two decades, Slovenia is observing catastrophic droughts and abundant precipitation resulting in floods, sometimes drought and floods occur even within the same year. The maximum snow cover depth and the depth of fresh snow decreased in the period 1961-2022.

In the last twenty years, occurrences of hydrological droughts of surface waters have become more frequent and intense compared to the previous period, and the variability between individual years has also increased. Very dry and very wet years alternate with intermediate periods of hydrologically normal years. The intensity of droughts during the growing season has become more frequent, although, in the last decade, it has been less intense than in the decade before.

Frequency of groundwater drought is increasing in recent decades in alluvial aquifers. 8 out of 10 years with highest intensity of groundwater drought in period 1981-2023 occurred after year 2000. Groundwater droughts with higher intensity is characteristic for winter while milder groundwater droughts mostly occur at the beginning of autumn. Groundwater drought intensity is also increasing seasonally with time between June and September when groundwater use is pronounced.

The frequency of agricultural drought in Slovenia has been increasing in recent decades. In the last twenty years, we have recorded 7 droughts that affected Slovenia at the scale of a natural disaster. Drought is occurring with increasing intensity and in areas and seasons where there have been no problems in the past. An additional risk for agricultural drought are rapidly developing droughts in summer ("flash droughts"), which occur especially during heat waves. Projections show that trend of increasing frequency and intensity of agricultural drought will continue in the future.