Cocaine Found in Colombia’s Water Systems

A new report has identified traces of cocaine and chemicals associated with illicit production in water systems serving more than 11.8 million people across five Colombian cities.

The report, Invisible Contamination: Cocaine and Chemical Inputs Associated with Illicit Production in Colombia’s Drinking Water, was published by the Center for a Secure Free Society (SFS), with sampling and laboratory analysis carried out with scientific support from Universidad de La Sabana. The samples were collected between Dec. 2025 and January 2026 in 12 cities and municipalities representing about 17 million people, or 32% of Colombia’s population.

The five cities where the study detected cocaine were Bogota, Cartagena, Popayan, Quibdo and Cali. Tap-water samples tested positive in the first four cities. In Cali, researchers found it in water entering the treatment system, so the result does not indicate a detection in finished drinking water. Together, the five cities serve more than 11.8 million people.

Cocaine traces appeared at several water-system points

The concentrations varied considerably between cities and sampling locations. In Bogota, the analysis detected 0.027 micrograms of cocaine per liter in treated water. Pre-treatment testing also detected 0.030 micrograms per liter at La Regadera and 0.018 micrograms per liter at Tibitoc, two key treatment plants in the municipal water system.

Cartagena recorded 0.032 micrograms per liter in water from the Canal del Dique, a major waterway connected to the city’s water system. The concentration fell to 0.005 micrograms per liter in treated water.

The study detected 0.004 micrograms per liter in tap water in Popayan and 0.002 micrograms per liter in Quibdo.

In Cali, the reported concentration was 0.030 micrograms per liter in water entering treatment at the Puerto Mallarino facility. The report does not identify that measurement as a result from finished tap water.

The measurements show that cocaine reached several points within the sampled water systems, including some samples collected after treatment. They do not, by themselves, establish a health effect from the concentrations measured, but they do show contamination within the system.

Other chemicals were also detected

Cocaine was not the only substance identified in the samples. The laboratory analysis also detected acetone, methanol, ammoniacal nitrogen, diesel and gasoline-related compounds at different locations. SFS associates these substances with chemical inputs linked to illicit cocaine production.

Acetone appeared in treated water in seven cities, with concentrations ranging from 2 to 32 micrograms per liter. The highest measurement came from Villavicencio.

Methanol exceeded the report’s reference value of 3 milligrams per liter at several locations. The highest measurements were 4.3 milligrams per liter in Florencia and 3.2 milligrams per liter in Monteria.

In Bogota, ammoniacal nitrogen reached 2.7 milligrams per liter, compared with the report’s reference value of 0.5 milligrams per liter.

Researchers also measured diesel levels reaching 22.2 milligrams per liter at the Tibitoc plant in Bogotá, alongside 9.9 milligrams per liter in water from Cartagena’s Canal del Dique.

The presence of these compounds does not establish that every detection originated from illicit drug production. Their sources can vary, and the report presents the results within its broader assessment of chemical contamination associated with the cocaine economy.

The study points to contamination beyond production areas

The sampling covered urban water systems rather than only locations close to coca cultivation or clandestine laboratories. SFS argues that chemicals associated with illicit production can enter waterways and move downstream, potentially reaching communities far from the source.

The study’s geographic scope also has limits. Its 12 sampled cities and municipalities represent about 17 million people, but the report notes that the analysis does not cover rural, riverine, and Indigenous communities located upstream from the sampled systems.

SFS connects the results to broader contamination risks facing local rivers, soils, ecosystems, and farmland. It also discusses the international supply chain for chemicals that can be diverted to illicit uses, including China’s role as a major producer and exporter of industrial chemicals. Those supply-chain observations come from the report and are not findings from the water samples themselves.

The findings do not establish a health risk

The report does not conclude that the detected concentrations have made Colombia’s drinking water unsafe. SFS says the measurements do not constitute a clinical diagnosis or establish an acute public-health emergency. While warning that repeated exposure could pose long-term risks, the report stresses the need for further testing.

The Bogota water utility defended the quality of the city’s drinking water after the findings became public. The agency said regulatory authorities have not officially notified it of any public health risks linked to the detected chemicals. Routine monitoring involves about 1,800 water-quality analyses monthly, according to the utility. Its water-quality risk index has historically remained at 0%, a benchmark that qualifies the supply as safe for human consumption.

The report’s measurements therefore document the presence of cocaine and several chemical compounds at specific points in Colombian water systems. Establishing whether those concentrations pose a health risk would require additional monitoring, independent verification, and toxicological assessment.