Wastewater based epidemiology (WBE) is the monitoring pathogens, pollutants and other chemical and biological markers to gain information about the population in a given wastewater catchment area. This can also involve sampling further upstream within the wastewater network, and downstream from treated effluent, biosolids and in the environment.

WBE can be used to compare the state of different catchment areas and how this changes over time. For biomarkers, genetic analysis can give greater depth of understanding of the origins and spread of disease. These techniques can also be used to monitor the efficacy of different wastewater treatment methods at removing various pathogens and chemical pollutants.