Netherlands residents spend nearly €1 billion per year on drugs

Netherlands residents spend an estimated 903 million euros per year on drugs, according to a new analysis of sewage water data by KWR, the research institute for the drinking water sector. This is the first time researchers have mapped out the value of Dutch drug consumption using sewage samples, Trouw reports.

The researchers analyzed the data on the residues of cocaine, speed, and ecstasy that ended up in the sewage system via urine. These substances were measured between 2015 and 2022 in 30 Dutch sewage treatment plants in both urban and rural areas.

Because a great deal of information is available about the purity of drugs in the Netherlands, the researchers could reliably deduce from the sewage samples how much of a certain drug was used. Sewage research into drug consumption has been conducted for some time now, but this is the first time researchers used that data to come to a street value.

The researchers stressed that there are a few uncertainties in their calculations. “We are assuming a fairly conservative estimate. We suspect that the actual value is higher,” KWR researcher Thomas ter Laak told Trouw. For example, they only examined one average week per year. “We chose not to examine days with peaks, such as around festivals or King’s Day, in order to obtain a structural picture.”

The researchers took into account that criminals regularly dump large quantities of drug waste into the sewer and excluded those figures from their estimate. “Then we see very abnormal peaks, we can clearly see when discharges have taken place and we then do not use that data,” Ter Laak said.

The analysis also confirmed that cocaine and ecstasy are used up to five times more in cities than in rural areas. “It fits the picture we have had for some time,” Ter Laak said. “But we can now substantiate it for the first time nationwide with research results.”

According to Ter Laak, this type of drug research in sewage is essential, especially because the estimates of the illegal drug market have many uncertainties. “This way, we can estimate which money flows are circulating in this black market,” he said. “With this amount, you can maintain an army of dealers.”

The KWR study also gives a more reliable picture of the size of the drug economy in the Netherlands while interviewing users provides information about who uses the drugs, he said. “Together, this provides insight into the size and consumers of the Dutch illegal drug market.”