Drought Impacts on Public Water Supply in Europe: a challenge of diversity and severity assessment

Drought degrades water quantity and quality, with impacts across multiple sectors. Public water supply is among the most impacted due to its essential role and high societal priority. Despite local evidence that drought can disrupt household water supply, impacts on public water supply remain less systematically studied. Their heterogeneous nature makes them difficult to assess and quantify. Yet, understanding public water supply’s vulnerability is crucial for safeguarding drinking water and supporting climate adaptation strategies. In this study, we analyzed text-based impact records on public water supply from the European Drought Impact Database (EDID) (https://drought.emergency.copernicus.eu/tumbo/edid), currently the most comprehensive collection of text-based drought impact records in Europe. We assessed the occurrence, diversity, and severity of drought impacts by analyzing temporal and spatial patterns in Europe and by investigating the details of the impact descriptions. Additionally, we tested whether the impacts and their severities were associated with natural and socio-economic factors. These potential vulnerability factors included climate, groundwater dependency, population density, and water management structures. Our results reveal substantial diversity in drought impacts on European public water supply, ranging from minor restrictions and demand-management measures to severe supply interruptions and emergency provisions. Impacts extend beyond drinking water to multiple uses, complicating their assessment. Geographically, the Mediterranean region shows a higher proportion of extremely severe impacts than central and northern Europe. The severity scoring system could be applied to the impact records to differentiate between levels of impact severity, but testing against natural and socio-economic factors did not reveal clear patterns. This analysis allowed evaluating the potential and limitations of EDID’s newly introduced severity scoring system in the public water supply sector, providing valuable insights for its future application. While refinement and further testing are needed, the severity scoring approach provides a starting point for quantifying drought impacts. EDID establishes a baseline for harmonized impact assessment and may support the development of adaptive water-management strategies across Europe.