These guidelines explain how to use Reportnet (the European Environment Agency's electro-nic infrastructure for data collection) for finding information and reporting information to the EU Commission in pursuance of the Urban Waste Water Treatment Directive (91/271/EEC). The reporting is organised in collaboration between DG Environment and the European Envi-ronment Agency (EEA).$$The guidelines addresses whole reporting process involving:acquiring reporting obligation from Reportnet, downloading data definition, reporting templates and supporting documents, dowloading IT-tool (DEM tool) from compilation, quality check and import/export of reported data, compiling tabular and geometric UWWTD data, uploading UWWTD data on Central Data Repository in Reportnet, confirmation of receipt, quality analysis of reported data$