Because of improved analytic technologies, organic micropullutants from urban drainage like pharmaceuticals, biocides and cosmetics have been increasingly detected in Svviss Waters in the last few years. The results arise questions about possible impacts on the aquatic environment and on people consuming drinking Water and foods. The article gives an overview of present measured data of persistent substances deriving from waste Water treatment plants in Swiss Waters. There is a need for further analysis, particularly with regard to the dynamics of the load and the occurrence of possible transformation products.