"Some scientists have recently turned to the sewer to develop a more accurate estimate of drug use. They examine tiny samples of raw sewage for the presence of illicit drugs and their metabolites in a science known as sewer epidemiology.4 These samples are essentially a diluted urine test collected from an entire community,5 making them akin to a “community urinalysis.”6 The basic science is simple: nearly every drug ingested into the body is eventually excreted and finds its way into the sewer system, allowing scientists to profile a community’s drug use based on objective data."


Hering, Christopher L., "Flushing the Fourth Amendment Down the Toilet: How Community Urinalysis Threatens Individual Liberty," Arizona Law Review (Tuscon, AZ: The University of Arizona, James E. Rogers College of Law, 2009), Volume 51, Issue 3, p. 742.