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Sentinel Wastewater Epidemiology Evaluation Project (SWEEP)

The Michigan Department of Health and Human Services currently tests wastewater for the SARS-CoV-2 virus at over 400 Michigan sites. The Sentinel Wastewater Epidemiology Evaluation Project (SWEEP) was created to give a regional and statewide overview of these efforts by providing a weekly analysis and interpretation of wastewater data from a subset of these monitoring sites.

There are multiple tabs on the Michigan COVID-19 SWEEP Sentinel Wastewater Dashboard below:

  • The "Current Data" tab displays several wastewater metrics for each site, including the number of weeks with positive tests, how the level of SARS-CoV-2 compares to previous samples, the size of that change, and recent trends. Corresponding COVID-19 case data are also provided in a pop-up window.
  • The “Map – All Data” tab displays how the level of SARS-CoV-2 compares to other samples over time.
  • The “Trends – All Data” tab displays wastewater trends over time.
  • The "Virus Detection" tab displays the number of sites reporting positive and negative test results to MDHHS each week.
  • The "About" tab provides definitions and information on data calculations.

What will we learn from this project?

The purpose of SWEEP, and of all COVID-19 wastewater monitoring, is to identify and track SARS-CoV-2 in our communities. The results can provide an early detection of the virus before people become sick or get tested and before cases are reported. Local health departments and their partners use this data to track COVID-19 in their communities and inform their public health responses.

SWEEP data will identify patterns in SARS-CoV-2 levels in wastewater and its geographic distribution. Over time, data from these wastewater treatment plants can be compared to other sampling sites and COVID-19 case data within the same region."

SWEEP Site Selection

A total of 20 wastewater treatment plants in 18 counties and the City of Detroit were selected to participate. These sites, referred to as sentinels, are distributed across the Michigan Economic Recovery Council (MERC) regions. MERC regions were developed by merging Michigan's Emergency Preparedness Regions and Michigan's labor sheds - the major areas of the state where people live and travel to work based on U.S. Department of Labor data - so that any outbreak resulting from a return to work could be handled effectively under public health laws.

  • Goal of 2 sentinel sites per MERC region
    • Exception: more in Detroit metro area due to larger population size
  • No more than one site per county
    • Exceptions: Ottawa County (two WWTPs cover the City of Holland), Detroit metro area
  • Sites must be wastewater treatment plants (WWTP)
  • The population in the WWTP service area is ≥5000
  • Composite samples (collected over a set time period instead of at a single point in time)
  • 2 or more samples collected per week

Overview of SWEEP

SWEEP Dashboard Interpretation Guide

For questions or more information, please email MDHHS at