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PFAS molecule

PFAS Basics

Here we provide some basic facts about per- and polyfluoroalkyl substances (PFAS) and answers to questions frequently asked by people who are new to PFAS such as private well owners, and small public water system users such as schools and trailer parks in rural areas.

What Are PFAS?

PFAS are a group of man-made chemicals used in a variety of consumer products and industries throughout the world. Two PFAS chemicals, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), were extensively produced and are the most studied and regulated of these chemicals. Many other PFAS exist. These PFAS are contained in some firefighting foams used to extinguish oil and gas fires. They have also been used in a number of industrial processes, and to make carpets, clothing, fabrics for furniture, paper packaging for food, and other materials (e.g., cookware) that are resistant to water, grease, and stains.

How do PFAS Compounds Get Into My Well and the Environment?

The widespread use of these products over the past 50 years and disposal routes shown below, have led these chemicals to become prevalent in the environment. PFAS have been released to the environment through industrial spills and disposal. Studies show some PFAS travel through soil and easily enter groundwater, where they may move long distances. Some experts suggest PFAS also disperse widely in air, either through evaporation or sublimation.

What are the Health Concerns Associated with PFAS?

In human studies, PFAS chemicals have been linked to an increased risk of cancer, reproductive and developmental problems, thyroid hormone disruption, high cholesterol, ulcerative colitis, and can affect the immune system. They are called “forever chemicals” because they build up in the human body where they can persist for years and do not easily break down in the environment. Infants and small children are particularly vulnerable as studies have shown children under 5 years who had the highest PFAS exposure have a weaker response to tetanus and diphtheria vaccines. The developing adaptive immune system in children being vulnerable to immunotoxicity could be weakened by exposure. You can read more at

How Can I Test My Well Water for PFAS?

Currently, there are three U.S. EPA testing methodologies for testing drinking water for PFAS. Laboratories will analyze drinking water for PFAS using either USEPA Method 537.1, 1633 or 533. These methods test for multiple PFAS compounds, including the PFAS compounds that are part of the current EPA Health Advisory Levels. If you want to have your drinking water tested, please contact us at

What Can I Do if PFAS Levels in my water are above the health advisory levels?

There are several treatment technologies that are capable of removing PFAS from drinking water, including granulated activated carbon (GAC), ion-exchange resin, and reverse-osmosis (RO). It is recommended that you evaluate the pros and cons for each type of treatment device to determine what is best for you.

Here are some companies you can contact for PFAS filtration:

How Are People Exposed to PFAS?

Drinking water contaminated with PFAS is considered to be a major source of exposure to PFAS. Studies have shown that water supplies in the vicinity of an industrial facility where PFAS were produced or used to manufacture other products, or an oil refinery, airfield or other location at which PFAS were used for firefighting have a higher probability of PFAS contamination.

There are a variety of other ways that people can be exposed to these chemicals and at different levels of exposure. People can be exposed to low levels of PFAS through food, which can become contaminated through contaminated soil and water used to grow the food and food packaging containing PFAS. People may be exposed to PFAS used in products to make them stain- and water-repellent or nonstick. These goods include carpets, leather and apparel, textiles, paper and packaging materials, and non-stick cookware.

People who work at PFAS production facilities, or facilities that manufacture goods made with PFAS, may be exposed in certain occupational settings or through contaminated air.  

An example of PFAS contamination by manufacturing processes is the case study of the Town of Blades, Delaware, where high levels of PFOA and PFOS were found in their wells.

At What Levels of PFAS Chemicals Should I Be Worried?

EPA has established health advisories for two of the PFAS chemicals PFOA and PFOS and has established the Health Advisory Levels (HAL) at 70 parts per trillion (ppt).  EPA's health advisories are non-enforceable and non-regulatory which implies that if a Public Water System (PWS) of certain size is found to have more than 70 ppt of these two PFAS, then they must treat the water and remove them. However, the HAL does not apply to smaller PWS and private well owners. Several states have designated PFAS as regulated chemicals, which means suppliers must test the drinking water for PFAS. In addition, these sates have set much lower Maximum Contamination Levels (MCL) for PFAS than the EPAs Health Advisory Level of 70ppt. You can read about PFAS regulation in different states here.

Should I Test My Private Well For PFAS?

Since water contaminated with PFAS does not smell or taste different, the only way to know if and how much PFAS you have in your water is to have your water tested for PFAS.

If you are being supplied by a PWS, ask your supplier if they test for PFAS. If you have your own well and your well is located within one to two miles of a known source of PFAS or of other water supplies where PFAS has been detected, you may wish to consider sampling your water source. Sources of PFAS may include airfields where certain firefighting foams were used in the past, firefighting training areas, certain manufacturing facilities, and some waste disposal/landfill sites. Your local health department may have information on historical or potential sources of PFAS, or other PFAS impacted water supplies, that may be in proximity to your private well. Because PFAS have been widely used in consumer products, it is possible that some septic systems and landfills may also be a source of PFAS in groundwater.

Table of PFAS Analytes Measured by Using EPA Methods 533 & 537.1

A total of 29 unique per- and polyfluoroalkyl substances (PFAS) can be effectively be measured  by method 537.1 and 533.

See EPA Table here.