If you want to know whether COVID-19 infections are rising or falling, look to the sewers. Wastewater monitoring (also known as wastewater surveillance or wastewater-based epidemiology) offers a novel way to monitor the health of a population as a whole.

Today, wastewater is the only timely source of information on COVID-19 available, and it’s what officials at the Centers for Disease Control and Prevention and World Health Organization turn to when assessing the risk of disease transmission. 

The rapid rise in wastewater research during the pandemic has yielded several new insights about this innovative approach to public health surveillance. Below are four key features of wastewater monitoring that address some commonly held misconceptions.