The Flemish drinking water companies can provide safe and qualitative drinking water when leaving the treatment plants. While we aim to maintain this quality during distribution, the introduction or regrowth of unwanted bacteria, that could affect odor and taste or even be harmful to human health, is still a recurring problem for the drinking water distribution networks. Today, most research is only focusing on the microbial component, while also protozoa and macroorganisms have been found in these networks. We hypothesize that the interplay between all trophic levels could influence the microbial community composition and ultimately the water quality. As of now, there are still a lot of question on the specific relationships within the DWDNs and to what extent, changing environmental conditions (climate change) exert an influence on this DWDN-biome and the water quality. By the development of a eDNA analysis pipeline to taxonomically identify both eukaryotic, as well as bacterial species, we want to charachterize the DWDN-biome in bad and good quality zones of the Flemish DWDN. We will then use this data to simulate changing environmental conditions (temperature, residence time and disinfection method) on our state-of-the-art drinking water pilot and investigate the effect on the biome and water quality.