Back in August of 2020, we made some changes to the Contaminated Site Tracker; you can read about those here.

This past December, we added an abundance of new contaminated sites, many of which are made possible by sampling data released by state agencies (especially in New Hampshire and California). In sum, we now have accounted for over 1,200 contaminated sites and more than 1,100 contaminated drinking water systems.

In our last update, we mentioned that we will no longer be updating the Historical PFAS Testing Results column. In lieu of this, we have added columns L through Q to the contaminated sites tab, which displays the maximum levels of PFOA, PFOS, PFOA+PFOS, and total PFAS recorded at a site, along with the matrix and date sampled. Please note that Max PFOA+PFOS and Max Total PFAS are those values from a single sample. While different samples from one site may have individually recorded higher values for individual chemical analytes, these columns account for the highest sum in one sample. This is to ensure that the represented data is not skewed higher than levels were actually recorded at a site.

Max Total PFAS accounts for all PFAS analytes sampled and reported. The individual breakdown of each analyte sampled can usually be found at the Most Recent PFAS Testing Results link, or in the Other PFAS Testing Results Historical column.

Also note that not all of these values are filled in for every site. For example, if Max PFOA and Max PFOS are both recorded for a site, but the Max PFOA+PFOS cell is empty, this means we were not able to determine if those values came from a single sample or different samples. Additionally, some reports only provide Max PFOA+PFOS, but they don’t convey the individual PFOA or PFOS levels. We will continue to update new and existing sites as we come across new information.

Please let us know if any discrepancies or questions arise as you are utilizing the database – we can be reached at