The Court of Audit of the Republic of Slovenia carried out a performance audit of the Ministry of the Environment and Spatial Planning in the period from 1 January 2016 to 31 December 2017 (the period covered by the audit), namely the audit of efficiency of long‑term drinking water resources conservation. Drinking water resources in Slovenia are mainly represented by groundwater bodies (21 in Slovenia) which are fed by various surface water bodies (155 in Slovenia). Due to their interdependence, groundwater and surface water bodies are both equally important for long‑term drinking water resources conservation.
 

The Court of Audit expressed an opinion that the Ministry was partially efficient in long‑term drinking water resources conservation. It thereby considered that taking measures in the field of drinking water resources conservation also depends on other relevant authorities, such as the Government, other competent ministries and local communities.

The Court of Audit established that the Ministry by state monitoring mostly gathers appropriate data on quantitative and quality status of groundwater and surface water bodies. According to water status assessment, which is made every 6 years, 3 out of 21 groundwater bodies and the majority of surface water bodies are holding poor water status. The Court of Audit also pointed out insufficient monitoring of deep aquifers as well as the fact that all substances which may be harmful to waters due to human activity cannot be detected by monitoring.

However, the Ministry identified the main reasons that might pose a risk to quantitative and quality status of waters in future. It concluded that human activity significantly affects all groundwater bodies and nearly all surface water bodies, while the quantity of pollutants remains similar to the previous years. The Court of Audit warned that actual water stress might be greater than estimated since the Ministry does not hold complete data thereon. Additionally, the Ministry failed to fully ensure comparability of data on water stress with previous years. The Court of Audit presented the impact of pollution on the quality of drinking water in the case of Dravska kotlina basin (exceeded limit values of pesticides and nitrates). It thereby stressed the importance of groundwater bodies conservation since the rehabilitation of polluted drinking water sources may extend over several generations.

The Court of Audit examined the data on the implementation of several groups of measures for reducing water stress, namely in the field of water protection areas designation, reducing the level of nitrates from agricultural resources, urban wastewater treatment, reducing hydromorphological burden on waters and in the field of inspection regarding water stress. The Court of Audit established that the Ministry only partially monitored and reported about the implementation of measures since not all ministries and bodies responsible for their implementation submitted their reports. Based on the available data the Court of Audit assessed that the implementation of measures is insufficient. There is thus a high probability that by the end of a 6-year planning period (by the year 2021) the measures pertaining to the field of water management will not be carried out as planned.

The Court of Audit demanded from the Ministry of the Environment and Spatial Planning to submit a response report indicating corrective measures concerning nitrate and atrazine groundwater contamination and provided several recommendations for improving the efficiency in the field of long-term drinking water resources conservation.