Wastewater surveillance analyzes wastewater samples from sewer systems to identify infectious diseases, antimicrobial resistance, and other health threats circulating in a community. It can reveal increases before they appear in clinical reports, providing a timely, cost-effective, population-level view that is not affected by individual testing or healthcare-seeking behavior. These data complement traditional surveillance activities and help public health agencies detect emerging threats, track trends, target interventions, evaluate actions, and make evidence-informed decisions to protect community health.

The COVID-19 pandemic demonstrated the value of wastewater surveillance for monitoring infectious diseases and strengthening public health preparedness. In response, federal, state, Tribal, local, and territorial agencies rapidly expanded monitoring to detect and track SARS-CoV-2 and other pathogens. A major milestone was the creation of CDC’s National Wastewater Surveillance System (NWSS), which supports the collection, analysis, and use of wastewater surveillance data to guide public health action.

NWSS has established a nationwide network that provides early warning of disease activity and complements traditional surveillance. Building on lessons from the pandemic, health departments and other partners now monitor a broader range of threats, including influenza, RSV, measles, antimicrobial resistance, and emerging pathogens. Partnerships among public health agencies, wastewater utilities, laboratories, academic institutions, and federal partners strengthen this work.

As these programs evolve, health departments are integrating wastewater data into routine practice, modernizing data systems, and improving analytic capabilities. The following stories illustrate how wastewater surveillance supports earlier detection, stronger situational awareness, informed decision-making, and better protection of community health.