CDC Wastewater Monitoring Program (NWSS)
- Source
- CDC Wastewater Monitoring Program / National Wastewater Surveillance System
- Update Cadence
- CDC public dashboards update weekly on Fridays; sampling varies by site
- Coverage
- Municipal wastewater sites across all 50 states, 7 territories, and some tribal communities
- Official URL
- View source
Fast Answer
CDC’s wastewater monitoring program is the official CDC wastewater monitoring source and the current public home for the National Wastewater Surveillance System (NWSS). It helps public health teams track community-level virus signals in sewage before or alongside clinical surveillance.
Use this source when you want to know whether wastewater can show early local activity, which diseases CDC shares publicly, and how to interpret a wastewater trend. Do not use it as an exact count of sick people, an address-level tap-water check, or a clinical decision tool.
Helpful CDC pages:
What It Measures
NWSS measures viral genetic material in wastewater samples from participating communities. CDC’s current public wastewater pages cover SARS-CoV-2 (COVID-19), influenza A, RSV, measles, avian influenza A(H5), and monkeypox.
How It Works
Participating wastewater programs collect community-level samples and send them to laboratories for testing. CDC explains that wastewater data can complement hospital, clinical testing, and other surveillance sources because it captures people who may not seek care or testing.
Sampling frequency is not identical at every site. CDC says public wastewater dashboards are updated weekly on Fridays with the previous week’s data, while local sample collection depends on the site, health department, lab capacity, and intended use.
What It Tells You
Wastewater surveillance gives a community-level signal that can show whether virus activity is increasing, decreasing, or present in a participating sewershed. It is strongest when interpreted with other public-health data rather than alone.
Limitations
- Geographic coverage is uneven; municipal sewer systems are better represented than homes or areas using septic systems.
- Cannot tell you how many people are sick, only that virus is present in the community.
- Concentration levels are affected by rainfall, industrial discharge, and lab methodology.
- Cannot distinguish between symptomatic and asymptomatic infections.
- CDC does not display some small, facility-specific, tribal, or data-quality-limited results publicly.