The present study aims at demonstrating the possibilities of on-line sensors for describing CSO emissions and river impacts. A continuous integrated monitoring, using state-of-the-art on-line sensors, was started in Berlin in 2010. It combines (i) continuous measurements of water quality and flow rates of combined sewer overflows (CSO) at one main CSO outlet and (ii) continuous measurements of water quality parameters at four sites within the urban stretch of the receiving river. UV-VIS probes provide continuous measurements of parameters such as chemical oxygen demand (COD) with relatively low uncertainties (10-30%). However, experience shows that on-line UV-VIS probes are not able to provide accurate measurements of water quality without being calibrated to local conditions. Several methodologies to analyze on-line CSO and river measurements are presented and illustrated with an exemplary event. Results show that reliable information such as the CSO load, the proportion of wastewater in CSO, the contribution of wastewater to CSO load, the first flush effect and the intensity of river impacts can be gained at high precision and temporal resolution. Given the broad range of high quality information from CSO impacts in the river to the characterization of CSO emissions, the study suggests the use of continuous integrated monitoring programs to support decisions on CSO management.