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Chemicals: Perfluoroalkyl and Polyfluoroalkyl (PFAS) Substances

Learn what you need to know about perfluoroalkyl and polyfluoroalkyl substances.

Also known as: PFAS

There are thousands of types of PFAS. The most common types are PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanoic sulfonic acid). View the Family Tree of PFAS (PDF).

What are PFAS?

PFAS are a group of chemicals made by humans. Since the 1950s, PFAS have been used in many consumer products and industrial processes. They have properties that resist heat, grease, and water.

Where are PFAS found?

While PFOA and PFOS have been phased out from their use in commercial products, they are still found in the environment from historical uses and in some firefighting foams. In addition, products are often made with other PFAS as replacements for PFOA and PFOS. These PFAS can be found in everyday products, such as:

  • Cleaning products.
  • Water-resistant fabrics, such as rain jackets, umbrellas and tents.
  • Grease-resistant paper.
  • Nonstick cookware.
  • Personal care products, like shampoo, dental floss, nail polish, and eye makeup.
  • Stain-resistant coatings used on carpets, upholstery, and other fabrics.

PFAS exposure

The main ways people can be exposed to PFAS include:

  • Drinking contaminated municipal or private well water.
  • Eating fish with high levels of PFAS.
  • Eating food grown or raised near places that used or made PFAS.
  • Eating food packaged in material made with PFAS.
  • Swallowing contaminated soil or dust.
  • Using some consumer products, such as ski wax, nonstick cookware, and stain and water repellant sprays for fabrics.

Learn more from the Agency for Toxic Substances and Disease Registry about how you can be exposed to PFAS.

What regulations and guidelines are available to protect people from PFAS?

Currently, there are no federal regulations for PFAS. However, some states have developed their own regulations for PFAS in drinking water. Wisconsin has established maximum contaminant levels (MCLs) for PFOA and PFOS in public drinking water.

Two-thirds of Wisconsinites use groundwater as their drinking water source. Wisconsin develops standards to protect people from substances that can be found in groundwater. To date, the Department of Health Services (DHS) has recommended groundwater standards for 18 PFAS. If the level of one or more PFAS is above the standard, the water may pose a health risk.

PFOA = 20* PFNA = 30 PFUnA = 3,000
PFOS = 20* PFHxS = 40 PFBA = 10,000
FOSA = 20* GenX = 300 PFTeA = 10,000
NEtFOSA = 20* PFDA = 300 PFHxA = 150,000
NEtFOSAA = 20* PFDoA = 500 PFODA = 400,000
NetFOSE = 20* DONA = 3,000 PFBS = 450,000/td>


  • All numbers are shown as nanograms of PFAS per liter of water (ng/L). This is equal to parts per trillion.
  • DHS recommends a combined standard of 20 ng/L for PFOA, PFOS, FOSA, NEtFOSA, NEtFOSAA, and NEtFOSE.

Learn more about these recommendations:

We also use a hazard index approach to assess the risk from mixtures of PFAS. This approach accounts for many types of PFAS that cause similar health effects when they are found together. This video explains more about the hazard index. If the hazard index is equal to or more than one, the water may pose a health risk.

View the PFAS Hazard Index video in Spanish.

View the PFAS Hazard Index video in Hmong.

PFAS health effects

Scientists are still learning about the health effects that different PFAS can have on the body.

How can PFAS affect health?

Scientists conduct research in both humans and animals to see how PFAS affect us.

Animal PFAS studies

Other research has tested PFAS in laboratory animals. Humans and animals don’t always react the same way to PFAS. Scientists, though, have ways to compare the results in animals to what they would be in humans. What they learn from this process helps them decide how to protect people from harm caused by chemicals. Animal studies have found that PFAS can affect development, the immune system, and the liver.

Research studies among humans have looked at a possible link between PFAS levels in the blood and harmful health effects. However, most studies have analyzed only a small number of chemicals. Not all PFAS have the same health effects. Research suggests that high levels of some PFAS may:

  • Increase cholesterol levels.
  • Decrease how well the body responds to vaccines.
  • Increase the risk of thyroid disease.
  • Decrease fertility in women.
  • Increase the risk of serious conditions like high blood pressure or pre-eclampsia during pregnancy.
  • Lower infant birth weights (the decrease in weight is small and may not affect health).

Most people in the U.S. have PFAS in their blood. PFAS levels are similar to low levels of other contaminants in the blood like flame retardants and plasticizers. You can have a PFAS blood test to check your levels. However, there isn’t enough research to know at what PFAS levels you should expect health problems.

How can I protect myself and my family from PFAS?

Because PFAS are so common in our environment, there’s no easy way to completely avoid them. There are some simple actions, though, that can limit our contact with them.

If you do not live near a site of environmental contamination, it is unlikely that PFAS are a problem in your drinking water. However, if you live near a site of PFAS contamination, you should connect with your local municipality and the Wisconsin Department of Natural Resources (DNR) to learn about available resources, including testing. To find out whether you live near a PFAS site, view this map.

If you have tested for and found PFAS in your drinking water, view this fact sheet, P-03212, and online PFAS Assessment Tool. This tool can help you evaluate the health risk from PFAS in your drinking water and determine whether you need a safer water source.

View Reducing PFAS in Your Drinking Water, P-03012. Use a water source that has safe levels of PFAS for:

  • Drinking.
  • Making foods that take up a lot of water, such as oatmeal, soup, or rice.
  • Mixing drinks, such as infant formula.

Safe water sources may include:

  • Bottled water that has been purified or filtered.
  • Water from a treatment system certified by ANSI/NSF Standards 53 or 58 to reduce PFAS.
  • Water from a source that has been tested for PFAS and doesn’t contain PFAS above the recommended standards.

You can use your tap water for doing laundry, washing dishes, brushing your teeth, or filling your swimming pool. To lower the chance of drinking small amounts of PFAS, remind swimmers not to swallow pool water.

View PFAS and Backyard Gardening, P-03111. It explains more about plant uptake of PFAS. It also has ways to reduce PFAS exposure if you garden in areas with known or suspected contamination.

View Eating Your Catch—Making Health Choices from Wisconsin Department of Natural Resources. Follow the guidelines that are in place where you fish to lower possible health risks. These risks come from common chemicals that harm fish, such as polychlorinated biphenyls and mercury. They also come from PFAS.

PFAS don’t easily enter the body through the skin. This means it’s usually okay to swim in surface water—which includes lakes, rivers, and ponds—even if it has PFAS. There are still important ways to avoid swallowing PFAS by accident:

  • Keep water out of your mouth—If water gets in your mouth, don’t swallow it. Besides PFAS, surface water can have algae, bacteria, viruses, and other harmful substances. They can pose a health risk for people and pets if they swallow them.
  • Avoid foam—Kids and pets should avoid foam since they are more likely to swallow it by accident. Foam found in surface water can come from natural causes, pollution, or both. Natural foams can have algae, bacteria, parasites, and decaying organic matter. Pollution foams can have chemical contaminants, such as PFAS.
  • Shower after swimming—Rinse off after swimming or touching surface water. Always wash your hands with soap and water before touching food.
  • Rinse your pets—Don’t forget to clean your pets after they swim in surface water. Don’t let them lick foam or algae off their fur.

Soil that has PFAS can come into your home from the outside. Dust also can have PFAS from common household products. Examples include stain-resistant carpeting or clothing that repels water. Vacuuming using a high efficiency particulate air (HEPA) filter reduces the amount of dirt and dust in your house.

Consumer products that may have PFAS include:

  • Cleaning products.
  • Nonstick cookware.
  • Paints, varnishes, and sealants. Follow directions carefully for safe use of these products.
  • Personal care products like shampoo or floss and cosmetics like nail polish and eye makeup.
  • Some grease-resistant paper, fast food containers or wrappers, microwave popcorn bags, pizza boxes, and candy wrappers.
  • Stain-resistant coatings on carpets, upholstery, and other fabrics.
  • Water-resistant clothes.

There have been recent federal efforts to remove PFAS from consumer products. These efforts have decreased how many people are exposed to PFAS from these products. However, some products still have PFAS.

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Last revised October 10, 2022