When residents are doing something they shouldn't—namely, illicit substances like crystal methamphetamine and cocaine—your influent shows it.

A team of researchers from Oregon State University and the University of Washington has developed an automated monitoring method that tests samples of municipal wastewater to detect traces of illegal drugs in the system. The data can be used to monitor patterns of drug use among residents.

“It's like a very diluted urine sample collected from an entire community,” says Jennifer Field, a chemist from OSU.

Drugs, both legal and otherwise, have been tracked in wastewater effluent for several years. However, this method tests the sewage as it enters a treatment plant, and detection is possible from very small samples taken over a 24-hour period.

Methamphetamine-related deaths in Oregon and Washington have gone up 300% in recent years, so it's a problem those states are eager to solve. Finding geographic patterns of drug consumption locates areas where city officials and law enforcement can focus on helping residents just say no.