 Over the last decade, effect-based monitoring, EBM, has become increasingly popular for water quality monitoring. Despite its recommendation in various guidelines, it is still not widely used in practice. This study reviews the available bioanalytical data from studies conducted on wastewater, drinking water, and reuse, and identifies knowledge gaps and priorities for action. The results provide an overview of the biological effects associated with raw and treated waters, the reduction of these effects through treatment, and a comparison of the detected responses with effect-based trigger values. It also highlights a lack of data for some biological effects and the need to further investigate effects like aryl hydrocarbon receptor agonism, genotoxicity, and oxidative stress. Drinking water treatment schemes appear to be more successful at eliminating biological effects compared to wastewater treatment, suggesting that priorities should be given to improving wastewater treatment for better environmental protection. This article was authored by Jerome Inault, John Francois Lauret, Peter A. Neal, and others. We are article.tv, links in the description below.