WQeMS aims to provide an operational Water Quality Emergency Monitoring Service to the water utilities industry in relation with the quality of the ‘water we drink’. Therefore, it will focus its activities on monitoring of lakes valorized by the water utilities for the delivery of drinking water. Sentinel data (i.e. Sentinel -2 and Sentinel-1) will be exploited for quality monitoring at a fine spatial resolution level, following validated processes with in situ data. The proposed WQeMS will exploit the Copernicus Data and Information Access Services (DIAS ONDA), instead of setting up its own download and processing infrastructure. Linkages with the existing Thematic Exploitation Platforms (TEPs), such as the Hydrology TEP for monitoring flood events and the Food Security TEP for supporting the sustainable intensification of farming from space will be pursued. Following cases are to be treated in real time in cooperation with drinking water production companies (public and private): - Slow developing phenomena (business-as-usual scenario), such as geogenic or anthropogenic release of potentially polluting elements through the bedrock or pollutants’ leaching in the underground aquifer through human rural activities, may influence water quality. Changes in the monitored chemical dissolved substances may be then detected. - Fast developing phenomena (e.g. floods spilling debris and mud or pollutant spills of chemicals in the lakes or algal bloom and potential release of toxins by cyanobacteria) produce huge quantities of contaminants at a short time interval bringing sanitation utilities at the edge of their performance capacity. Monitoring of the extent of the effluents in the lake; thus, providing a warning about the risk of water contamination, assist in mitigating impact, both for the water drinking water production and the environment.