Groundwater organisms provide ecosystem services for the quality of ground and surface waters (Mammola et al., 2019). These micro-organisms and invertebrates can transform and degrade contaminants, or  maintain hydraulic conductivity. However, biodiversity assessments for aquifers are generally not available. To monitor and assess biodiversity levels in the aquifers and their surroundings, eDNA will be used to ensure the possibility to study rare and/or elusive species.