Organic compounds specific to human sewage sources could potentially be used as tracers to identify the presence of human waste in receiving waters. These compounds could be used to track and identify inputs of human waste from sources such as treatment plant effluent, CSOs, septic systems, and stormwater outfalls. Recent analytical technology has enabled the analysis of a number of chemicals including hormones, pharmaceuticals, and personal care products that have not been available before. Researchers have been using these analytical methods to determine if the sources of fecal contamination in surface waters are related to sewage or other sources. 

This literature review looked at 14 primary and 27 secondary references representing studies in both the United States and other countries. The review focused on chemical tracers unique to human wastes, including artificial sweeteners, caffeine, nicotine, and certain pharmaceuticals and personal care products. The review identified 29 compounds as potential sewage tracers. Of these compounds, caffeine, sucralose and acesulfame (artificial sweeteners), carbamazepine (anti-epilepsy drug), and metformin (diabetes drug) were viewed as the most promising.