PFAS (Polyfluoroalkyl Substances)

What are PFAS? 

PFAS (polyfluoroalkyl substances) are manmade synthetic chemical compounds and exist in industrial and consumer products. The US Environmental Protection Agency has issued Health Advisory Levels for these substances for several years.  

GenX Chemicals (PFAS Compound) 

The GenX term is used by US EPA to describe compounds that have “replaced” PFOS and PFOA. They have similar properties. These compounds are “eliminated from the human body” more quickly than PFOA and PFOS, but the concern is how they impact the liver function.   

How are PFAS containments introduced into the environment? 

PFAS contaminants are not natural in the environment, but test results reveal detectable levels in groundwater tables, rivers, and lakes in Wisconsin. Research and studies indicate that firefighting foams containing levels of PFAS used during firefighting exercises have migrated into ground water tables. Other contributors of PFAS are industry release into surface waters, landfills, wastewater effluents, wax paper, fast food containers, and cosmetics.  


Can PFAS be removed? 

PFAS containments do not readily breakdown in the environment and can be difficult to remove from drinking water sources. Currently, ground water systems are the target for testing and surface water systems are under review. The US Environmental Protection Agency advises that granular activated carbon (GAC) treatment is successful in removing PFAS containments in a water system’s treatment facility, but also point-of-use filters installed in your home have been successful.  

What are the drinking water regulations and/or standards for PFAS? 

On March 14, 2023, the Environmental Protection Agency released new draft standards on Maximum Contaminant Levels (MCLs) for six PFAS (PFOS, PFOA, PFNA, PFBS, PFHxS, and GenX). The draft communication also included a conceptual combination of traditional Maximum Contaminant Levels (MCLs) and a novel Hazard Index (HI). According to US EPA, the Hazard Index concept would be a health risk assessment tool that can be used to calculate multiple chemical compound exposures occurring at the same time.  

 The proposed MCLs and HI are as follows:

  • PFOA: 4.0 ng/L or parts per trillion
  • PFOS: 4.0 ng/L or parts per trillion
  • 1.0 (unitless, NOT 1 ppt) Hazard Index (HI) for a mixture of PFNA, PFHxS, PFBS, and GenX

 US EPA Proposed PFAS National Primary Drinking Water Regulation Fact Sheet: FACT SHEET (

US EPA Lifetime Health Advisory Levels: 

Interim(draft)- PFOA is 0.004 parts per trillion and 0.02 parts per trillion for PFOS 

Final- GenX  is 10 parts per trillion and 2,000 parts per trillion for PFBS.  

US EPA Minimum Reporting Limits: 

PFOA is 4 parts per trillion GenX is 5 parts per trillion 

PFOS is 4 parts per trillion PFBS is 3 parts per trillion 

Wisconsin Department of Health Services continues to review and research the health effects of PFOA and PFOS. On August 1, 2022, Wisconsin Department of Natural Resources set a 0.000070 mg/L (70 ppt) MCL for PFOA and PFOS. This level is set for the combined concentration of PFOA and PFOS. In 2021 Sheboygan Water Utility testing, PFOS was found to be detectable at a low-level result of 2.3 parts per trillion.  

More information regarding Wisconsin Administrative Code, ch. NR 105 Rule and timeline:  

PFAS Surface Water Criteria | | Wisconsin DNR 

What are US EPA drinking water health advisories? 

The US Environmental Protection Agency defines drinking water health advisories as “providing information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. The EPA's health advisories are non-enforceable and nonregulatory and provide technical information to drinking water system operators, as well as federal, state, Tribal, and local officials on health effects, analytical methodologies, and treatment technologies associated with drinking water contamination.  

Additional US EPA health advisory information:  

Drinking Water Health Advisories for PFAS Fact Sheet for Public Water Systems (PFOA, PFOS, GenX Chemicals and PFBS) ( 

Questions and Answers: Drinking Water Health Advisories for PFOA, PFOS, GenX Chemicals and PFBS | US EPA 

Has Sheboygan Water Utility tested its drinking water for PFAS? 

Yes, the Sheboygan Water Utility has tested its drinking water for (6) PFAS contaminants in 2014 and (18) PFAS contaminants in 2021. During 2023 testing, 16 of 18 contaminants were not detectable.

The Sheboygan Water Utility has tested its drinking water for the following PFAS compounds: 

  • Perfluorooctanoic acid (PFOA) *
  • Perfluorooctanesulfonic acid (PFOS) *
  • Perfluorobutanesulfonic acid (PFBS)
  • Perfluoroheptanoic acid (PFHpA)
  • Perfluorohexanesulfonic acid (PFHxS)
  • Perfluorononanoic acid (PFNA)
  • Perfluorodecanoic acid (PFDA)
  • Perfluorohexanoic acid (PFHxA)
  • Perfluorododecanoic acid (PFDoA)
  • Perfluorotridecanoic acid (PFTrDA)
  • Perfluoroundecanoic acid (PFUnA)
  • N-ethyl Perfluorooctanesulfonamidoacetic acid
  • N-methyl Perfluorooctanesulfonamidoacetic acid
  • HFPO-DA/GenX
  • 9Cl-PF3ONS/F-53B Major
  • 11Cl-PF3OUdS/F-53B Minor
  • Perfluorotetradecanoic acid (PFTeDA)

 In 2023, WDNR has required PFOA/PFOS quarterly sampling/testing:

  • 1st quarter test results
    •  PFOA: 1.9 ng/L or parts per trillion
    •  PFOS: 1.9 ng/L or parts per trillion
  • 2nd Quarter test results:
    • PFOA: NOT DETECTABLE <1.9ng/L or parts per trillion
    • PFOS: NOT DETECTABLE <1.9ng/L or parts per trillion

PFOA and PFOS contaminants are detectable, but well below the proposed draft standard of 4.0 ng/L. 

Will the Sheboygan Water Utility conduct additional PFAS/PFOS testing? 

Yes, the utility will participate in additional PFAS/PFOS testing referred to as the Unregulated Contaminant Monitoring Rule 5 (UCRM5). The monitoring program is administered by the Environmental Protection Agency via Wisconsin Department of Natural Resources. UCMR5 testing is scheduled to begin between 2023 and 2025. 

US EPA Link: Fifth Unregulated Contaminant Monitoring Rule | US EPA 

Customer Communications: 

SWU Consumer Confidence Report

Tap Analysis 

Additional information from State Agencies: 

Wisconsin Department of Health Service 

Per- and Polyfluoroalkyl Substances (PFAS) | Wisconsin Department of Health Services 

Wisconsin Department of Natural Resources 

Wisconsin PFAS Interactive Data Viewer

PFAS | Wisconsin DNR 

Consumption Advisories and PFAS | | Wisconsin DNR