PFAS Monitoring Results in Woodbury Municipal Wells

The City of Woodbury regularly monitors the water quality of each of the wells for contaminants, including PFAS, based on state and federal regulations. Results from this monitoring can be found in the most recent Water Quality Report. 

The city recognizes the importance of treating all wells for PFAS in the future, regardless of PFAS levels. Currently, nine of the 19 wells exceed the Minnesota Department of Health health risk index for PFAS. Six of those wells are being treated at the temporary Water Treatment Plant to appropriate standards while the other three wells are offline. The city will continue to regularly monitor PFAS levels at each of the 19 wells, as well as monitor changes in state and federal regulations. 

Monitoring Results 

(Includes all wells in operation, with and without treatment)

Updated March 2023

PFAS TypeAmount (Combined Range in wells in operation)MDH Health Risk LimitMDH Health Based GuidelineEPA Guideline
Heptafluorobutyric acid (PFBA)194 to 440 parts per trillion (ppt)7,000 parts per trillion (ppt)N/AN/A
Perlfuorooctanic acid (PFOA)Less than 3 to 49 ppt35 pptN/A4 ppt
Perfluorooctanesulfonic acid (PFOS)Less than 3 to 32 ppt300 ppt15 ppt4 ppt
Perfluorobutanesulfonic acid (PFBS)Less than 1.9 to 6.2 ppt 7,000 ppt100 ppt2,000 ppt
Perfluoropentanoic acid (PFPeA)6.3 to 17.2 ppt Not establishedN/AN/A
Perfluorohexanoic acid (PFHxA)3.3 to 10 pptNot established200 pptN/A
Perluorohexanesulphonic acid (PFHxS)Less than 1.8 to 13 ppt Not established47 pptN/A





"Parts per trillion" means the number of units of the chemical, in its pure form, found in every trillion units of water.

From a general perspective, the City of Woodbury pumped approximately 2.6 billion gallons of water in 2020. That means a PFAS detected at a level of 25 ppt (parts per trillion) would equal about an 8-ounce cup (or 0.06 gallons) of the substance in 2.6 billion (2,600,000,000) gallons of water.