Wastewater monitoring · Illinois
COVID Flow
See how COVID is moving through Illinois communities this week.
Illinois activity index
-1.75
Week-over-week +51.4%
What this project does
COVID Flow turns CDC NWSS wastewater data into weekly activity indices for Illinois and Cook County. The focus is clear public data, not case counts or personal risk scores.
What it measures
SARS-CoV-2 RNA in wastewater. Each sample reflects viral shedding from everyone connected to that sewer network.
How to read it
Indices near zero mean typical shedding for that location. Trends show whether levels are rising, falling, or stable week to week.
What it is not
Not a case count, hospital forecast, or tool to judge your individual risk. Use it for community context alongside official health guidance.
Regional dashboards
Weekly indices, historical charts, and data quality notes from the public NWSS pipeline.
In plain terms
Wastewater measures viral shedding from a whole community, not individual infections. Levels can shift before clinical testing catches up in some outbreaks.
COVID Flow publishes weekly activity indices and trend labels from CDC NWSS. We do not estimate case counts, hospital burden, or personal risk. For medical decisions, follow official public health guidance.