The CDC aggregates samples from wastewater, as does Biobot analytics.

Perhaps the most informative data are from Biobot analytics, as they show concentration over time (CDC shows change over time or presence/absence only).

Line plot of covid in wastewater over time

Or zooming in on the last three months:

Line plot of covid in wastewater over last three months

The plots below are all for sliding windows showing change over 15 days. I am plotting them by the final date in the window. Some states have great, detailed coverage in the CDC’s data – Tennessee is not one of them. I’m plotting data from the four closest sites to our region. This is based on “closest” of March 27, 2022; it’s possible that new sites will come online (for example, UT Knoxville had been tracking covid in its wastewater, but these data are not available currently).

The plot below shows the percentage change of covid in wastewater over 15 day intervals: positive means it’s increasing over the 15 day period, negative shows it’s going down. This is just relative to the window: going up slightly if they’re already high or if they’re very low means different things for amount of virus in a community. At most, it can decline by 100%; it can increase by a nearly infinite amount. To handle this, I’m plotting it with bounds of -100 to 100% gain over the 15 day interval.

Scatter plot of covid change over time

This plot shows percentage of samples where covid was detected over a 15 day window.

Scatter plot of covid detection over time