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 20 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 20 wells, as well as monitor changes in state and federal regulations. 

Monitoring Results

Updated September 2022

PFAS TypeAmount (Combined Range in All 19 Wells)MDH Health Rick LimitMDH Health Based GuidelineEPA Guideline
Heptafluorobutyric acid (PFBA)0.21 to 0.39 parts per billion (ppb)7 parts per billion (ppb) or 7,000 parts per trillion (ppt)N/AN/A
Perlfuorooctanic acid (PFOA)0.0021 to 0.042 ppb0.035 ppb or 35 pptN/A0.004 ppt
Perfluorooctanesulfonic acid (PFOS)
Less than 0.0016 to 0.028 ppb0.03 ppb or 300 ppt0.015 ppb or 15 ppt0.02 ppt
Perfluorobutanesulfonic acid (PFBS)Less than 0.0017 to 0.013 ppb (reported below the laboratory limit)7 ppb or 7,000 ppt0.1 ppb or 100 ppt2,000 ppt
Perfluoropentanoic acid (PFPeA)0.0065 to 0.016 ppb (reported below the laboratory limit)Not establishedN/AN/A
Perfluorohexanoic acid (PFHxA)0.0024 to 0.016 ppbNot established0.2 ppb or 200 pptN/A
Perluorohexanesulphonic acid (PFHxS)Less than 0.0018 to 0.062 ppb (reported below the laboratory limit)Not established0.047 ppb or 47 pptN/A

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

"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 0.025 ppb (parts per billion) 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.