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Due to a technical issue, wastewater data is currently delayed for COVID-19, influenza A, and RSV. Data will be updated as soon as possible.
Wastewater Influenza A State and Territory Trends
Influenza A Wastewater Monitoring in the U.S.
Wastewater monitoring can detect viruses spreading from one person to another within a community earlier than clinical testing and before people who are sick go to their doctor or hospital. It can also detect infections without symptoms. If you see increased wastewater viral activity levels, it might indicate that there is a higher risk of infection. See how to protect yourself from respiratory viruses.
Wastewater data are updated every Friday with the previous week's data, which allows for data to be reviewed for accuracy. Data may change as more reports are received.
This page shows the current wastewater viral activity level of influenza A for the overall state or territory. If states do not have historical data available, the state/territory page may not be available. This page also shows state/territory, regional, and national trends over time.
Current Site Levels – Download Data (CSV)
Trend Over Time – Download Data (CSV)
All State/Territory Wastewater Viral Activity Levels – Link to Dataset (JSON) | Download Data (CSV)
On August 15, 2025, CDC updated the methodology used to calculate the wastewater viral activity level. For more information, visit CDC’s Wastewater Surveillance Data Methodology page.
About the Wastewater Viral Activity Level: The wastewater viral activity level indicates whether the amount of virus in the wastewater is very low, low, moderate, high, or very high. The wastewater viral activity levels may indicate the risk of infection in an area. The wastewater viral activity levels are categorized as follows:
- Up to 2.7 – Very Low
- Greater than 2.7 and up to 6.2 – Low
- Greater than 6.2 and up to 11.2 – Moderate
- Greater than 11.2 and up to 17.6 – High
- Greater than 17.6 – Very High
No Data: States or territories without sufficient data to estimate the wastewater viral activity level for the previous week are indicated as “No Data.” A label of “No Data” means that either:
- No data were reported this week from sites within the state or territory
- Data were reported this week, but sites within the state or territory do not have enough data (at least 8 weeks with consistent methodology) to estimate the wastewater viral activity level in the last week.
National, regional, and state/territory data represent the median values across all wastewater treatment plants in the respective area. To learn more on how the wastewater viral activity level is calculated, visit CDC’s Wastewater Surveillance Data Methodology page.
Trends Over Time Graph Regions: When you select a state/territory, the region line corresponds to the region that state belongs to. States and territories are grouped into the following U.S Census Bureau regions:
- West: Alaska, Arizona, California, Colorado, Guam, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming (N=14)
- Midwest: Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, Wisconsin (N=12)
- Northeast: Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Puerto Rico, Rhode Island, Vermont (N=10)
- South: Arkansas, Alabama, Delaware, District of Columbia, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, West Virginia (N=17)
Data Limitations: Wastewater data cannot determine the source of influenza A viruses. Detections could come from a human or from an animal (like a bird) or an animal product (like milk from an infected cow).
