The latest findings from the largest European project monitoring illicit drug use through wastewater analysis are released today in Wastewater analysis and drugs — a European multi-city study, published by the Europe-wide SCORE group, in association with the European Union Drugs Agency (EUDA). This year’s findings highlight a marked decline in MDMA residues across the participating cities, alongside strong increases in ketamine and cocaine detections.
The project analysed wastewater in 115 European cities from 25 countries (23 EU, Norway + Türkiye) to explore the drug-taking behaviours of their inhabitants. The study analysed daily wastewater samples in the catchment areas of wastewater treatment plants over a one-week period between March and May 2025. Wastewater samples from a population of 72 million people were analysed for traces of five stimulant drugs (amphetamine, cocaine, methamphetamine, MDMA and ketamine) as well as cannabis. The study reveals diverging patterns for cannabis, amphetamine and methamphetamine.
Despite results varying considerably across the study locations, it is noteworthy that all six drugs investigated were found in almost every participating city. The project findings revealed distinct geographical and temporal patterns of drug use across European cities. Overall, within countries, less divergence in drug use patterns was seen between the largest city and smaller cities (see 'City variations' below).
The SCORE group has been conducting annual wastewater monitoring campaigns since 2011. In the latest round, international data (from Brazil, Canada, Chile, Iceland, New Zealand, South Korea, Switzerland, the United Kingdom and the United States) are presented and comparisons made with the European study locations.
Key findings
• MDMA : Overall MDMA loads in wastewater dropped by 16 % between 2024 and 2025 in cities reporting data for both years. Of the 78 cities with data for both 2024 and 2025, 48 (62 %) reported a decrease in MDMA detections, 12 (15 %) a stable situation and 18 (23 %) an increase. The decline was most evident in cities in Germany, Austria and Slovenia and is larger than that observed in 2020, when almost half of the cities reported decreases during COVID-19 nightlife closures. In 2025, the highest mass loads of MDMA were recorded in cities in Belgium, Spain, the Netherlands and Slovenia. MDMA was detected in all but one European city (Nova Gorica, Slovenia). Among locations outside the EU, only cities in New Zealand reported levels comparable to those seen in the European cities with the highest loads.
• Ketamine : Overall ketamine loads in wastewater increased by nearly 41 % between 2024 and 2025 in cities reporting data for both years. Among the 66 cities with data for both 2024 and 2025, 40 (61 %) reported an increase in ketamine residues, 14 (21 %) remained stable and 12 (18 %) showed a decrease. In 2025, the highest mass loads were detected in cities in Belgium, Germany and the Netherlands. Nine cities (in Belgium, Cyprus, Lithuania, Hungary and Slovenia) reported no detectable ketamine residues. Levels reported in cities in Canada and the United Kingdom exceeded those recorded in the European cities with the highest loads.
• Cocaine : Overall cocaine loads in wastewater increased by nearly 22 % between 2024 and 2025 in cities reporting data for both years. Of the 85 cities with data for both 2024 and 2025, 48 (57 %) reported an increase in cocaine residues, 21 (25 %) remained stable and 16 (19 %) showed a decrease. Cocaine detections remain highest in western and southern European cities, particularly in Belgium, Spain and the Netherlands, although traces were found in most eastern European cities, where some increases continue to be seen. Levels reported in cities in Canada, Chile, Switzerland and the United Kingdom matched, or exceeded, those recorded in the European cities with the highest loads.
• Amphetamine : The level of amphetamine residues varied considerably across study locations. The highest levels were reported in cities in northern and central Europe (Belgium, Denmark, Germany, the Netherlands, Sweden and Norway), with much lower levels found in cities in the south (e.g. in Italy, Cyprus and Türkiye). Three cities in Portugal and Slovenia reported no detection of amphetamine loads in 2025. Of the 82 cities with data on amphetamine residues for 2024 and 2025, 36 (44 %) reported an increase, 27 (33 %) a decrease and 19 (23 %) remained stable.
• Methamphetamine : Traditionally concentrated in cities in Czechia and Slovakia, this drug is now also present in cities in Germany, Spain, Cyprus, Lithuania, the Netherlands, Norway and Türkiye. Elsewhere, methamphetamine loads were low, although some increases were reported in central and northern European cities. Of the 80 cities with data for 2024 and 2025, 37 (46 %) reported an increase, 28 (35 %) a decrease and 15 (19 %) remained stable. Levels reported in cities in Australia, Canada and the United States exceeded those recorded in the European cities with the highest loads.
• Cannabis : Diverging trends continue to be observed for cannabis. Of the 63 cities with data for 2024 and 2025, 21 (33 %) cities reported an increase in detections of the cannabis metabolite (THC-COOH), 28 (44 %) a decrease, while 14 (22 %) remained stable. The highest loads were found in western and central European cities, particularly in Germany, the Netherlands and Slovenia. Levels reported in cities in Canada and the United States exceeded those recorded in the European cities with the highest loads.
• City variations: In 2025, most countries with multiple study sites reported no marked differences between patterns observed in large cities (i.e. city with the largest population in each country) and smaller locations, with the exception of cocaine and MDMA.
• Weekly patterns: Wastewater analysis can detect fluctuations in weekly patterns of illicit drug use. More than 75 % of the 115 cities showed higher residues of cocaine and MDMA at the weekend (Friday–Monday), while almost half of them showed higher loads of ketamine. In contrast, residues of amphetamine, methamphetamine and cannabis (THC-COOH) were distributed more evenly throughout the week.
Dr Lorraine Nolan, EUDA Executive Director, says: ‘Europe’s wastewater tells the story of a drug phenomenon that is widespread, varied and in constant flux. This year’s study, covering 115 European cities, reveals a marked decline in traces of MDMA, alongside continued signs that cocaine and ketamine detections are on the rise. Wastewater analysis helps us track these shifts early to better understand where attention and resources are needed and to inform evidence-based public health and policy responses across Europe’.
