MWRA Wastewater Covid-19 Tracking

MWRA's wastewater testing detects virus levels in sewage and offers a way to detect Covid-19 infection trends before testing of individuals. Note: You can click and drag on an area of the first graph to zoom in, and click on series in the legend to turn them off and on.

Only communities in eastern Mass that are part of the MWRA sewage systems are included. To see additional MWRA testing data, go to the Massachusetts Water Resources Authority website

Scroll down to see detailed graphs with error bars for recent 60 days in north and south regions.

Daily Samples, Recent 60 Days with Error Bars


Massachusetts Known COVID-19 Cases by City/Town as of August 31, 2023

Average Daily per 100K and percent positive are for the prior 14 days. May take a few seconds to load.


Stopped updating July 8, 2022 when DPH stopped posting daily data Mon-Fri

Massachusetts Known COVID-19 Cases vs Tests (historical)

Note: Mondays starting July 2021 include data for Saturdays & Sundays, too.

Massachusetts Known COVID-19 Deaths - no longer updates

Massachusetts Known COVID-19 Hospitalizations - no longer updates

Most of this data come from the Massachusetts Department of Public Health Web site. State-wide data here no longer updates as of July 8, 2022 when DPH stopped posting daily data. You can see their data updates weekly. I still update data by community weekly because long-term trends are not available by city/town on the Massachusetts dashboard.

MWRA wastewater testing comes from the pilot project with Biobot; more info and raw data available from the MWRA. That continues to update multiple times per week.

Some historical data from early in the pandemic, including deaths, comes from the New York Times GitHub repository. Note that the Times data included probable cases from serology tests but I didn't include that when reporting Mass DPH data, since I was more interested in seeing current trends than overall infections (serology tests can be positive for someone who was contagious weeks ago but is recovered).

As with all U.S. Covid-19 data, these tables and graphs are undercounting the actual number of cases. That's due to the inadequate testing. While testing rates have improved, some cases are still being missed.

This application was created by Sharon Machlis with the R programming language and R packages shiny, data.table, ggplot2, plotly, leaflet, DT, and glue, among others. It wouldn't have been possible without the incredible contributions of the R core team and R package authors to make this free platform possible. (Any and all errors in the data presentation are, however, mine alone.)

Infrastructure provided by Digital Ocean.