Wastewater-based epidemiology (WBE) enables the retrieval of epidemiological information from urban wastewater via the analysis of specific human metabolic excretion products (biomarkers). It has the unique advantage of providing evidence-based, objective, and near-real-time information of a defined community at different spatial and temporal resolutions. WBE was applied for the first time in 2005 in Italy and later on, in 2011, was used to monitor spatial trends of illicit drugs use in Europe by the SCORE (Sewage analysis CORE group) network in collaboration with the European Monitoring Centre for Drugs and Drug Addiction. Since then, the network has expanded worldwide and monitoring has been extended to a wider panel of human habits, i.e. illicit drugs, alcohol, nicotine, caffeine, pharmaceuticals. Illicit drugs use is so far the habit studied most extensively. Annual worldwide monitoring campaigns organized in the framework of the SCORE network enabled the long term monitoring of illicit drugs use in the last years, as well as the monitoring of spatial profiles of consumption. These data are very relevant nowadays for EMCDDA and UNODC and are included in their annual reports on drug consumptions. WBE is considered an additional drug use indicator and can provide update information on emerging trends.