DHS recommended groundwater standards for PFAS
On November 6, 2020, the Wisconsin Department of Health Services (DHS) recommended groundwater standards to the DNR for a number of different substances, including 16 additional types of PFAS compounds. (The agency had previously recommended standards for two types called PFOA and PFOS.)
All wells in Madison more than meet all of the DHS recommended groundwater standards for PFAS.
Below is a list of PFAS compounds, along with the recommended standard for each and the highest level of each substance found in Madison’s wells during 2020 testing. A list of levels found at Well 15 during 2019 testing is also included. Well 15 is not currently in service.
(Click here to view a map of Madison’s municipal well facilities.)
| PFAS | WI DHS recommendation (ng/L or parts per trillion) | Maximum Level (2020) | Well with Max Level (2020) | Well 15 (2019) |
|---|---|---|---|---|
| PFOA | 20* | 1.8 | Well 14 | 6.1 |
| PFOS | 20* | 1.8 | Well 16 | 5.9 |
| FOSA | 20* | 4.4^ | Well 31 | ND |
| NEtFOSE | 20* | 1.5 | Well 12 | ND |
| NEtFOSA | 20* | ND | -- | ND |
| NEtFOSAA | 20* | ND | -- | ND |
| PFBA | 10,000 | 37 | Well 09 | 3.0 |
| PFBS | 450,000 | 1.7 | Well 14 | 3.4 |
| PFHxA | 150,000 | 2.2 | Well 14 | 6.2 |
| PFHXS | 40 | 5.0 | Well 14 | 21 |
| PFNA | 30 | ND | -- | ND |
| PFDA | 300 | ND | -- | ND |
| PFUnA | 3000 | ND | -- | ND |
| PFDoA | 500 | 0.56 | Well 06 | ND |
| PFTeA | 10,000 | 0.52 | Well 06 | ND |
| PFODA | 400,000 | na | -- | na |
| DONA | 3000 | ND | -- | ND |
| GenX | 300 | ND | -- | ND |
* Recommended that combined level of six PFAS compounds (PFOA, PFOS, FOSA, NEtFOSE, NEtFOSA, & NEtFOSAA) be below 20 ng/L
^Present in laboratory method blank; may reflect cross-contamination at lab
ND = not detected
na = not analyzed