PFAS Frequently Asked Questions

Pouring Fresh Tap Water Into a Glass

Recent news articles have raised awareness, and concern, with PFAS levels prevalent in Wisconsin drinking water. We have prepared a FAQ in an effort to remain transparent and provide information about this substance, as well as share MPU’s testing results. If you have further questions, please call our customer service department at 920-683-4600.

1. What is PFAS?
Per-and Polyfluoroalkyl Substances (PFAS) are a group of manufactured chemicals that have been used in industry and consumer products since the 1940s because of their useful properties. There are thousands of different PFAS, some of which have been more widely used and studied than others. One common concern of PFAS is that many break down very slowly and can build up in people, animals, and the environment over time.
2. How do PFAS get into the environment?

PFAS can be present in our water, soil, air, and food as well as in materials found in our homes or workplaces. Here are some examples:

  • Soil and water at, or near, waste sites such as landfills, disposal sites, and some hazardous waste sites.
  • Aqueous film-forming foams (AFFFs) used to extinguish flammable liquid-based fires. Such foams are used in training and emergency response events at airports, shipyards, military bases, firefighting training facilities, chemical plants, and refineries.
  • Manufacturing or chemical production facilities that produce or use PFAS. For example, chrome plating, electronics, and certain textile and paper manufacturers.
  • Some foods such as fish caught from contaminated water or dairy products from livestock that have been exposed to PFAS.
  • Food packaging such as grease-resistant paper, fast food containers/wrappers, microwave popcorn bags, pizza boxes, or candy wrappers.
  • Household products such as stain and water-repellent used on carpets, upholstery or clothing/other fabrics. Cleaning products, non-stick cookware, paints, varnishes, or sealants.
  • Personal care products such as some shampoos, dental floss, and cosmetics.
  • Biosolids
  • Public drinking water systems and private drinking water wells
3. What does research say about PFAS?
Current scientific research suggests that exposure to high levels of certain PFAS may lead to adverse health outcomes. However, research is still being conducted to determine how different levels of exposure to different PFAS can affect our health, including low levels over long periods of time, especially in children.
4. How does PFAS entering the drinking water system?

PFAS can enter soil, groundwater, and surface water near places where these chemicals were released into the environment. Some of the common sources of PFAS pollution include airports where firefighting foam was discharged, firefighting foam testing facilities, and manufacturing or chemical production facilities that produce or use PFAS.

The highest concentrations of PFAS in drinking water supplies have been found in water systems that draw water from groundwater wells. PFAS are also being found, but at much lower concentrations, in water systems that draw water from lakes and rivers, including the Great Lakes.

5. Does the Environmental Protection Agency (EPA) or the Wisconsin Department of Natural Resource (WDNR) have drinking water regulations and/or standards for PFAS?
PFAS are typically measured in parts per trillion when measuring their presence in drinking water. One part per trillion is similar to one drop of water in 20 Olympic-sized swimming pools. In 2022, the Wisconsin Department of Natural Resources set the maximum allowable concentration of PFAS in drinking water at 70 parts per trillion. This is a higher concentration than was recommended by Wisconsin’s Department of Health Services, which recommended a maximum allowable level of 20 parts per trillion.

In June of 2022, the EPA set an interim health advisory limit for two specific types of PFAS. Those levels were set at 0.004 parts per trillion for PFOA and 0.02 parts per trillion for PFOS. As of March 14, 2023, the EPA has now made a proposal on drinking water standards. These standards are anticipated to be finalized by the end of 2023. 

6. Has MPU tested for PFAS in our drinking water?

Yes. MPU recently tested the water entering the water distribution system for PFAS as required by the fifth EPA Unregulated Contaminate Monitoring Rule (UCMR5). Eighteen PFAS substances were tested and twelve of them were not detected. Six analytes were detected at low levels including:

  • perfluorobutanesulfonic acid (PFBS)
  • perfluoroheptanoic acid (PFHpA)
  • perfluorohexanoic acid (PFHxA)
  • perfluorohexanesulfonic acid (PFHxS)
  • perfluorooctanoic acid (PFOA)
  • perfluorooctanesulfonic acid (PFOS)

The Wisconsin Department of Health Services (DHS) recommends evaluating risk based on a hazard index, which is calculated by comparing the levels of each PFAS to its recommended standards and adding those ratios together. If the hazard index is equal to or above 1, the water may pose a health risk. MPU’s hazard risk is 0.177 (unitless). MPU will test multiple times throughout 2023 and will update this FAQ accordingly. MPU’s top priority is the safety of our drinking water and transparency to our customers. If you have any questions about these results, please call our customer service at 920-683-4600

7. Where else can I learn about PFAS in drinking water?

The information referenced above was compiled from the websites below, as well as additional information.

Environmental Protection Agency

Wisconsin Department of Natural Resources

Wisconsin Department of Health Services (DHS)


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