Water in rural Colorado town tests positive for marijuana's psychoactive ingredient

Officials in rural Hugo, Colo. (Best Places map), on Thursday warned residents not to drink or bathe in water or allow pets to drink it, because water supplies tested positive for tetrahydrocannabinol, the main psychoactive compound in marijuana, John Ingold reports for The Denver Post. "There have been no reports of illnesses or any symptoms of impairment from drinking the water, officials said." Hugo, located in Lincoln County, does not have any commercial marijuana operations. The county of 5,420 residents has 62 medical-marijuana patients, according to the state Department of Public Health and Environment.

"Concerns about the water were first raised by a Hugo company using quick 'field tests' to check employees for THC," Ingold writes. "The simple tests are similar in function to home pregnancy tests in that they can return only two results: positive or negative." The company conducting the tests "had been getting inconsistent results and decided to test a vial of tap water, expecting it to be negative. Instead, the test came back positive, and the company called authorities."

"Lincoln County officials conducted 10 other field tests, using two different types of test kits, on the town’s water and six came back positive," Ingold writes. "Authorities later isolated the positive results to a single well—well No. 1, about a mile south of Hugo’s small downtown." The well showed signs of forced entry, but officials said it was unclear when the damage occurred.

The source of the chemical remains a mystery, on more than one level. THC is not soluble in water.