Per- and polyfluoroalkyl Substances (PFAS)

Q: What are these chemicals and where do they come from?
A: Per- and polyfluoroalkyl substances (PFAS) are a family of thousands of human-made chemicals with many useful properties including the ability to repel water, prevent staining and increase heat resistance. PFAS have many industrial and consumer uses including the coating of fabrics, carpets, electrical wire, and non-stick cookware, in food packaging (e.g., microwave popcorn bags and fast-food wrappers), as a mist suppressant in metal plating, and in firefighting foam used by firefighters to put out petroleum fires. (Home fire extinguishers do not typically contain PFAS.) Some of the most studied PFAS in terms of health effects are perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), hexafluoropropylene oxide-dimer acid (HFPO-DA, also known by the trade name GenX), perfluorohexanoic acid (PFHxA), perfluorobutane sulfonic acid (PFBS), and perfluorobutanoic acid (PFBA). These PFAS are found with the highest frequencies and concentrations in the environment, in humans, and/or in wildlife. Also, we know the most about the harmful effects and environmental fate of these PFAS. While less is known about chlorinated polyfluoroether sulfonic acids, two (6:2 and 8:2 Cl-PFESAs also known as 9Cl-PF3ONS and 11Cl-PF3OUdS) have been detected sporadically in CT private wells.  In some instances, they have been the sole PFAS identified, underscoring the need to evaluate their potential risk to human health. While PFOS and PFOA have been phased out of production in the US, they are still produced internationally and imported into the US in consumer products. In addition, they are very persistent chemicals and can remain in the environment for long periods after being removed from the marketplace.   

Q:  What is the current Connecticut DPH drinking water Action Level for PFAS and how was it developed?

A:  The CT DPH has derived individual health-based drinking water Action Levels  for 10 PFAS. Action Levels are guidelines for drinking water that are protective of public health and also feasible based upon analytical detection and treatment technology. This means that an Action Level concentration can be detected in drinking water by certified laboratories and that treatment systems are available to remove the contaminant(s) to a concentration that is below the Action Level. The 10 PFAS for which CT has developed Action Levels have enough toxicological data available to support development of health-based Action Levels. These PFAS include the most widely studied PFAS that have also been detected in human blood more frequently and at higher concentrations than other PFAS. CT DPH established Action Levels for four PFAS (PFOA, PFOS, PFNA, PFHxS) in June 2022 and for another six PFAS (GenX, PFHxA, PFBS, PFBA, 6:2 Cl-PFESA, 8:2 Cl-PFESA) in June 2023. The current Action Levels are listed in the Table below.






CT Drinking Water Action Level

(nanograms per liter; ng/L)^




6:2 chloropolyfluoroether sulfonic acid (6:2 Cl-PFESA, 9Cl-PF3ONS,*

F-53B major)






8:2 chloropolyfluoroether sulfonic acid (8:2 Cl-PFESA, 11Cl-PF3OUdS,**

F-53B minor)






Perfluorooctane sulfonic acid (PFOS)






Perfluorononanoic acid (PFNA)






Perfluorooctanoic acid (PFOA)






Hexafluoropropylene oxide dimer acid (HFPO-DA; GenX)






Perfluorohexane sulfonic acid (PFHxS)






Perfluorohexanoic acid (PFHxA)






Perfluorobutane sulfonic acid (PFBS)






Perfluorobutanoic acid (PFBA)




* EPA Methods 533 & 537.1 use 9Cl-PF3ONS (9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid) for this PFAS.

** EPA Methods 533 & 537.1 use 11Cl-PF3OUdS (11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid) for this PFAS.

CT DPH develops its drinking water Action Levels by considering health impacts to the most sensitive and most exposed populations across all stages of human development. These PFAS Action Levels are based on the most sensitive, human-relevant effects seen in laboratory animals exposed to PFOS (immune effects); PFNA, PFOA, PFHxA (developmental effects); PFHxS, PFBS, PFBA (thyroid effects); or GenX, 6:2 Cl-PFESA (liver effects). The data are insufficient for 8:2 Cl-PFESA so its Action Level is based on toxicity data for 6:2 Cl-PFESA. The chemical-specific approach reflects the evolving scientific evidence on the toxicity of PFAS and is more protective of public health than the summed approach used previously in CT. Also, the resulting individual Action Levels are within the range of drinking water guidance and standards most recently derived by the federal Agency for Toxic Substances and Disease Registry (ATSDR) and by other states, including most of CT’s neighboring states.


Q: There are thousands of PFAS chemicals. Why has CT only derived drinking water action levels for some of them?

A: The decision to develop a drinking water Action Level for any chemical, including PFAS, is based on evidence that the chemical (1) has been detected in drinking water or is anticipated to occur in drinking water (e.g., based on patterns of use and/or detection in other environmental media such as soil or groundwater), (2) is known or anticipated to be harmful to humans, and (3) has sufficient toxicological data available to support derivation of an Action Level. The PFAS analytical methods currently used for drinking water analyze for a total of 29 PFAS chemicals out of the thousands of PFAS that are currently known to exist. CT DPH will continue to evaluate the evolving toxicological, environmental occurrence data and federal regulatory actions to determine the need and our capability to develop Action Levels for more PFAS and update the existing ones.



Q:  How do these chemicals get into drinking water?

A:The way in which PFAS reach groundwater is still being investigated. Drinking water contamination has occurred near industries manufacturing or using these chemicals to make consumer products. PFAS use at metal plating facilities as a mist suppressant can also be a source of groundwater contamination. Because of their presence in firefighting foams, it is possible that fire training schools, fire departments, airports, and sites where there was a major fire may have releases of PFAS. Landfills can be sources of PFAS because many types of wastes that contain PFAS can end up in landfills. Once on the ground, these chemicals can gradually migrate down through the soil when it rains and impact groundwater. PFAS do not biodegrade and are known to be persistent in the environment. Once a release has occurred that has impacted groundwater, it is possible, depending on the magnitude of the release and hydrologic conditions, for PFAS to travel far away from the release area.

Many consumer products also contain PFAS, so it is possible that PFAS can be washed down the drain and into septic systems, thus becoming a source of groundwater pollution and potentially impacting nearby wells. For more information on sources of PFAS, please refer to the Connecticut Department of Energy and Environmental Protection’s PFAS webpage.


Q:  If I have PFAS in my water, what precautions should I be taking for my pets, farm animals, home grown produce, and irrigation of my garden?



CT DPH has identified limited data about how PFAS might affect the health of cats and dogs. Out of an abundance of caution, homeowners can choose to use an alternative water source for their pets if their drinking water exceeds a CT DPH Drinking Water Action Level.

Chicken eggs

There are good data that show that the amount of long-chain PFAS (such as PFOS, PFOA, PFHxS) in chicken eggs is directly correlated with the amount of PFAS in drinking water consumed by hens (short-chain PFAS such as PFHxA and PFBS are not readily transferred from drinking water to chicken eggs). Results from a recent study indicate that hens given drinking water with a combined level of PFOS, PFOA, and PFHxS that exceeds 3000 ppt (ng/L) are likely to produce eggs with PFAS concentrations that would exceed the limit set by the Australian Government for human consumption (the US Food and Drug Administration [FDA] has not set any limits for PFAS in foods). Therefore, CT DPH advises that drinking water with the sum of PFOS, PFOA, and PFHxS concentrations greater than 3000 ppt not be used for hens if the hens are producing eggs for human consumption. This guidance assumes that hens do not have significant exposure to PFOS, PFOA, or PFHxS from soil and/or feed.

PFAS in meat

Long-chain PFAS have been shown to transfer into the meat of livestock (cattle, sheep, pigs, goats) chickens, and game (deer, boar, duck) consuming PFAS-contaminated water and/or feed. Although the exposure pathways and how they relate to environmental contamination levels are still not well understood, in most cases, contaminated water is the primary exposure source. The FDA has not set guidance values for PFAS in meat. If you have a contaminated water source and plan to use your animals for human consumption, CT DPH advises, out of an abundance of caution, that you use an alternative water source for your farm animals, or contact CT DPH for specific advice at or (860) 509-7740

PFAS in milk

Some PFAS have been shown to be readily absorbed and excreted into maternal milk of laboratory rodents, dairy cows, sheep and humans. In the past few years, several farms outside of CT have detected elevated levels of one specific PFAS, PFOS, in cow’s milk. The US Department of Agriculture (USDA) has not set guidance values for any PFAS in milk. Since the cows’ exposure to PFOS and several other PFAS was mainly through contaminated feed (and possibly drinking water), CT DPH is unable to determine the levels of PFAS in drinking water that would produce unacceptable levels of PFAS in milk. Given the findings about uptake of PFAS into maternal milk of lab rodents, dairy cows, sheep, and humans, it is possible that goats exposed to elevated PFAS in their water source could also accumulate elevated PFAS levels in their milk. If you have a contaminated water source and plan to use your cow, sheep, or goat milk or milk products for human consumption, CT DPH advises, out of an abundance of caution, that you use an alternative water source or contact CT DPH for specific advice at or (860) 509-7740. 

Use of water for irrigation of home-grown produce

The answer for whether produce is safe for consumption if it is irrigated with water contaminated with PFAS is complicated and will need to be addressed on a case-by-case basis. The amount of PFAS transferred to produce will vary based upon the amount and type of PFAS found in irrigation water and the soil itself, the type of soil, and the specific type of produce. In general, the amount of plant uptake increases with decreasing PFAS chain-length and decreasing level of organic carbon content of soil, and is greater in roots (i.e., carrots, potatoes) than shoots (leafy vegetables). The amount of produce that you consume and whether there has been long-term use of enrichment/biosolids containing PFAS also need to be considered when evaluating safe consumption of home-grown produce. Call DPH directly at or (860) 509-7740 for assistance.

CT DPH continues to monitor the rapidly evolving science on PFAS uptake into plants, animals and animal products. As more definitive information becomes available, we will update this FAQ.


Q: Can I remove PFAS by boiling my water?

A: PFAS cannot be removed by boiling the water. In fact, it may increase the PFAS concentration as the water will evaporate, but most PFAS will remain.

Q: I am a customer of a public water system. How can I find out if my water has been tested for PFAS?

A:  If you are concerned about PFAS in your public drinking water, CT DPH recommends you contact your local water utility to learn more about your drinking water and to learn whether they have monitoring data for PFAS or can provide any specific recommendations for your community.


Q: How do I know if bottled water is safe?

A:Bottled water is regulated by the Department of Consumer Protection as a food product. Many retail water bottlers publish water quality testing data, and while PFAS chemicals are not regulated in bottled water, many bottlers do test for it and include the information on their web pages. Some water bottlers use numerous sources and water quality may vary depending on the source location. If you are making your own purchasing decisions about bottled water, make sure that when you search for water quality data, you are viewing the data from the correct source.

Water bottlers with sources in CT are required to collect samples prior to any water treatment and annually test the bottled water source for unregulated contaminants that have CT Drinking Water Action Levels (including PFAS). There are currently five bottlers with CT DPH-approved sources that are testing for PFAS. CT DPH reviews the results and if a result exceeds a CT DPH Drinking Water Action Level, CT DPH  may require the bottler to discontinue use of the source until the bottler can demonstrate that the water being sold to customers is below the CT DPH Drinking Water Action Level.

Bottled water delivered to homes in conjunction with a Connecticut Department of Energy and Environmental Protection (DEEP) investigation has been tested for PFAS per the contract DEEP has with its bottled water vendor.


Q:  How can PFAS affect my health?

A: The main health concerns from ingestion of the PFAS compounds for which CT DPH has drinking water Action Levels come from studies in laboratory animals which consistently show effects on the liver and immune system, and on growth, reproduction, and fetal development. PFAS can also affect the endocrine (e.g., thyroid) and hormonal systems and can disturb blood lipids such as cholesterol in lab animals. Studies of human populations exposed to elevated levels of these PFAS generally support the effects seen in animals. Some studies of populations exposed to PFOA have also shown an increased risk for kidney cancer, and at very high exposure levels, for testicular cancer. Our bodies eliminate long-chain PFAS such as PFOS, PFOA, PFNA, PFHxS, and the Cl-PFESAs very slowly, so they can build up over time with continued exposure. Short-chain PFAS, such as GenX and PFBS, do not build up as easily in the body over time; however, they have been shown to cause similar health effects in laboratory animals as the long-chain ones.

If your drinking water has PFAS at levels greater than the CT drinking water Action Levels and you have been drinking the water or using it for cooking for many years, you may have an increased chance of experiencing health problems like the ones mentioned above. However, it is important to understand that consuming water with PFAS levels greater than the Action Levels does not mean that health effects will occur. Action Levels are developed with many health protective safety factors. Also, your level of risk depends on a number of factors including the level of PFAS in the water, how long you have been drinking the water (i.e. exposure duration) and whether you are a member of a sensitive population group. Pregnant people, infants and children are at higher risk because of PFAS effects on pregnancy outcomes and fetal, infant and child growth and development. If you have specific health concerns, you may wish to consult with your health care practitioner.

PFAS are not readily absorbed by your skin, so dermal absorption through bathing, showering, swimming, and washing dishes in water containing PFAS is not a significant source of exposure.


Q:  Why have states set different acceptable levels for PFAS in drinking water?

A: A number of states that have identified PFAS contamination have developed health-based guidelines and enforceable standards for PFAS in drinking water. While states use the same standardized risk assessment approach for developing acceptable drinking water concentrations, there are many points in the process where professional scientific judgement is needed. Different decisions in the risk assessment process can result in variations in drinking water standards and guidelines, each of which may be scientifically defensible. In addition, some states have set acceptable PFAS drinking water levels more recently than other states. Consideration of newer PFAS toxicological data can result in differing acceptable levels.

Some states have established their own PFAS drinking water standards and guidelines because of the absence of an enforceable federal Environmental Protection Agency (EPA) Maximum Contaminant Level (MCL) for PFAS. Currently there are EPA lifetime health advisories (guidelines, not enforceable standards) for PFBS and GenX, as well as interim ones for PFOA and PFOS. In March 2023, EPA proposed MCLs (enforceable standards) for six PFAS. However, the proposed MCLs are not final. The EPA draft MCLs have no immediate impact on public water systems in the state, and no immediate action is required. Until final MCLs for PFAS are released, DPH will continue to provide guidance to public water systems with PFAS detections based on our current health-based Action Levels.


Q:  Should I test my blood for PFAS?

A: CT DPH generally does not recommend testing your blood for PFAS. There are several reasons why. A PFAS blood test can tell you what your levels are at the time the blood was drawn, but not whether levels in your body are “safe” or “unsafe” or whether your health has been or will be impacted by PFAS. Virtually everyone in the U.S. (and the world) has measurable amounts of PFAS in their body because PFAS chemicals have been so widely used in commercial and industrial products for decades. Many of the health issues that have been associated with exposure to PFAS (such as increased cholesterol and decreased thyroid hormone levels) commonly occur in the population even without high levels of PFAS in the blood. These health issues can be caused by many different factors, and there is no way to know or predict if PFAS exposure has caused or will cause a health problem. It can also be complicated to get a PFAS blood test. It is not a routine test, not many laboratories can analyze blood for PFAS, and it is likely that health insurance would not cover the cost. Finally, a PFAS blood test will not provide information to identify a new health problem, nor will it provide information about treatment. If you are concerned about your exposure and wish to have your blood tested for PFAS, you should speak with your healthcare provider.

Because blood tests for PFAS are not widely available, the Centers for Disease Control and Prevention (CDC) and the Agency for Toxic Substances and Disease Registry (ATSDR) have developed a PFAS blood level estimation tool. This tool is intended for community members with exposure to PFAS through drinking water who would like more information about levels of PFAS in their blood. The estimates from this tool might be helpful when considering ways you might be exposed to PFAS and options for reducing exposure, or when speaking with your healthcare provider.  

There are several important limitations of this tool that users should be aware of:

  • The tool is not designed to determine connections between PFAS exposure and health effects and will not tell you if your PFAS exposures will make you sick now or later in life.

  • Only four PFAS are included in the tool (PFOA, PFOS, PFHxS and PFNA).

  • Users must have information on the concentrations of one or more of the four PFAS in their drinking water.

  • The tool assumes that PFAS concentrations in bottled water are zero. This may or may not be an accurate assumption. PFAS is not regulated in all bottled water. All bottled water is not necessarily tested for PFAS and some may have detectable levels of PFAS.

  • Blood level estimates from the tool do not provide the same level of certainty that an actual blood test would and therefore the tool is not intended to replace actual PFAS blood testing.


The CDC/ATSDR PFAS Blood Level Estimation Tool can be accessed here.


Q:  How can I limit my overall exposure to PFAS?

A: The best way to limit your exposure to PFAS is to become knowledgeable about your potential sources of PFAS exposure.

We can be exposed to PFAS not only through drinking PFAS contaminated water, but also through pathways such as: eating foods packaged in PFAS containing materials; using consumer products containing PFAS such as non-stick cookware, stain resistant carpeting, and water repellant clothing; and eating foods contaminated with PFAS, such as fish and seafood. Nearly everyone has low levels of PFAS in their blood. These background levels likely come from consumer products and food packaging. You may still have some PFAS in your body years after the chemicals have been phased out because of their persistence in the environment and their slow removal from the body.

Recommendations to reduce your exposure to PFAS:

    • If you know that your tap water contains PFAS, particularly if the PFAS levels exceed a CT DPH Drinking Water Action Level, you should consider reducing or eliminating your use of the tap water. You can do this by using an alternate source of water for drinking or cooking (such as bottled water) or by installing treatment to lower the PFAS levels in the water you drink. Refer to the Private Well and Bottled Water sections for more information.
    • Limit your use of consumer products containing PFAS. You can do this by avoiding products that contain the words “fluoro or “perfluoro” in the ingredient list, and by avoiding products with stain-resistance treatments. The Environmental Protection Agency’s Safer Choice label as well as nonprofit organizations including GreenScreen and Green Seal are identifying products that are safer for use.  While DPH does not endorse any particular organization or products, consumers may wish to consider the product certification programs employed by each in making personal purchasing decisions. CT DEEP’s PFAS webpage also has information about consumer products containing PFAS.
    • Follow the Connecticut Fish Consumption Advisory for information about eating fish caught in Connecticut waters. Follow fish and game consumption advisories set by other states if you fish or hunt outside Connecticut.

    • Follow US EPA additional advice on how to limit your exposure to PFAS.



Q:  I have a well, should I test the water for PFAS? How can I test my well for PFAS?

A: If your well is located near a suspected or probable source of PFAS, (refer to DEEP’s webpage for information about PFAS sources) you might consider testing. PFAS testing is currently not broadly recommended for all private well users, because of the complexity of proper sample collection, cost, and the limited number of labs approved for testing for PFAS. If you’d like to consider testing, the list of labs certified to test for PFAS in drinking water can be found on the CT DPH’s Environmental Laboratory Certification Program’s website.  

CT DPH encourages private well owners to test their drinking water for general potability and other common naturally occurring and human-made contaminants. For general private well recommendations on what to test for, why and how often, refer to the CT DPH's website: If your well water has contamination that exceeds any concentration on CT’s Action Level List, CT DPH recommends that you take actions to reduce your exposure to your contaminated well water. The best way to do this is to use an alternate source of water for drinking and cooking (such as bottled water) or by installing treatment to lower the contaminant levels in the water you drink.

Because of the concern about PFAS exposure and developmental effects, it is especially important that water contaminated with PFAS at concentrations greater than the Action Levels not be used to prepare infant formula and that people who are pregnant or lactating and children should use an alternative source of water for drinking and cooking.


Q:  Does the State test private wells for PFAS?

A: CT DEEP Remediation Division’s Potable Water Program can assist with testing private drinking water supply wells for PFAS in certain circumstances.  Because there are presently limited financial resources to support private well sampling for PFAS, DEEP has focused its efforts on testing private wells located near drinking water supply wells that have been tested and have confirmed detections of PFAS above a CT DPH Drinking Water Action Level or in areas where soil and/or groundwater is contaminated with PFAS in close proximity to private wells, and where a responsible party is unknown or unable to sample(Contamination may be identified through independent testing performed by a public water system, a home owner, a remediation contractor or other entity.When an area of PFAS contamination that threatens private wells is reported to DEEP and a responsible party has not been identified, an ‘iterative’ approach is used to evaluate the presence of PFAS in surrounding private drinking water wells.  If initial sampling near the source of contamination, detects the presence of PFAS in private wells above a CT DPH Drinking Water Action Level, the sampling area is expanded to test additional wells in the area. This process continues until the extent of private wells impacted is understood. This is a process that is consistently followed for all human-made contaminants, not only for PFAS.


Q:  What happens if there are PFAS in my well?

A: If you tested on your own and PFAS are detected, please notify DEEP at and DPH at for additional guidance.

If your well is being tested through a targeted investigation being conducted by DEEP and PFAS are detected in your well water above a CT DPH Drinking Water Action Level for PFAS, then DEEP will arrange to have bottled water delivered to you on an interim basis and will evaluate and provide for installation of an appropriate treatment system, as funding permits. The type of treatment system will be dependent on case specifics but will most likely consist of a granular activated carbon system.  Arrangements to have your water treatment system routinely maintained and serviced by a licensed water treatment professional for the duration of this investigation will also be made.


Does the home water treatment system that I have work to remove PFAS? What types of treatment address PFAS in drinking water?

A:  Viable treatment options for PFAS reduction include granular activated carbon (GAC), anion exchange treatment, and point of use reverse osmosis (RO). Treatment effectiveness is dependent on treatment sizing, contact time, and how well the device is maintained. For specific devices, it may be best to check with the manufacturer of your treatment device.

To find products certified by the National Sanitation Foundation (NSF) to reduce PFOA and PFOS, please refer to: NSF Protocol P473 Drinking Water Treatment – PFOA & PFOS. There are currently no treatment devices certified to reduce PFAS other than PFOA and PFOS. For more information, please refer to the DPH Per- and Polyfluoroalkyl (PFAS) Detections in Private Well Water guidance and visit the Environmental Protection Agency website: Reducing PFAS in Drinking Water with Treatment Technologies.



Contacts & Resource 




External Resources


Circular Letters

2022-27 Environmental Health & Drinking Water Branch Update for Public Water Systems Regarding Per- and Polyfluoroalkyl Substances (PFAS)

2021-87 Bottled Water Sources to Sample for Unregulated Contaminants

2019-03 Reminder to Complete Land Use Inventory Table Source Water PFAS Vulnerability Assessment

2018-28 Environmental Protection Agency (EPA) Toxicity Assessments for GenX Compounds and Perfluorobutane Sulfonic Acid (PFBS)

2018-20 Requirement to Update an Evaluation of Source Water Protection Measures and Request to Sample Drinking Water Sources for Perfluoroalkyl Substances (PFAS)

2018-19 Drinking Water Section Update for Public Water Systems regarding Per- and Polyfluoroalkyl Substances (PFAS)

2016-16 EPA Drinking Water Health Advisory for Two Perfluorinated Compounds