Minnesota Wastewater
What the sewers say about COVID-19, flu and RSV, one treatment plant at a time.
People shed virus before they feel sick and whether or not they ever get tested, so wastewater is one of the earliest signals of a rising wave. Each circle is a treatment plant sampled by the Minnesota Department of Health, sized by the number of people it serves and shaded by how high this week's level is compared with that plant's own readings since June 2025.
Hover over, tap or tab to a plant to see its trend against the statewide average.
Table view for the selected week
| Plant | Region | People served | 4-week average | Level vs. own history |
|---|
About the data
Data from the Minnesota Department of Health wastewater dashboard, which publishes weekly averages for each treatment plant. MDH's Public Health Laboratory tests most plants twice a week with digital PCR and divides each virus concentration by pepper mild mottle virus (PMMoV), a plant virus common in human waste, to adjust for how much sewage a plant handles. The values are relative, not copies per liter.
Because plants differ in their sewers, sampling and populations, each circle's shade compares its four-week average with that same plant's own four-week averages since : the lowest fifth of its readings is "very low" and the highest fifth is "very high." A gray dot means the virus was not detected over those four weeks; a dashed circle means the plant has no recent samples. The statewide line is MDH's population-weighted average.
Plant locations are approximate (city or plant site); MDH publishes county but not coordinates. On September 7, 2026, Duluth (WLSSD) moved its sampling point, so compare its readings before and after that date with caution. Data downloaded .
I made this map at Mapathon: All About Maps, a tcplot event held in Minneapolis on October 24, 2026.