Bristol, England, recorded the highest ketamine level of any European city in the latest Europe-wide wastewater study. Its 2025 sampling week averaged 338.95 milligrams of ketamine per 1,000 people per day, more than double the next European city, Amsterdam (149.33 mg), followed by Berlin (132.23 mg). Bristol’s highest single day was a Saturday, at 551.57 mg per 1,000 people.
The study, run by the SCORE research group with the European Union Drugs Agency (EUDA), tested daily wastewater samples for one week between March and May 2025 in 115 European cities in 25 countries, covering about 72 million people. Overall ketamine loads rose by nearly 41% between 2024 and 2025 in the cities that reported both years. The figures estimate community-wide drug residues in sewage; they do not count individual users.
Source: EUDA, Drugs in municipal wastewater in Europe: source data (2026); see also the EUDA news release on the 2026 wastewater findings.
Image: Reflections in the Floating Harbour, Bristol. Credit: Derek Harper, CC BY-SA 2.0, via Wikimedia Commons.