In 2023, the U.S. Environmental Protection Agency (EPA) took a significant step by proposing the first-ever federal drinking water limits for PFOA and PFOS, two chemicals that have contaminated drinking water supplies across the United States. These "forever chemicals" don't break down in the environment or in your body, and decades of scientific research have linked them to serious health problems including thyroid disease, liver damage, and weakened immune function. If you're concerned about what's in your tap water, this guide explains everything you need to know about PFOA and PFOS, where they're found, the health risks they pose, and what you can do to protect your family.
What Are PFOA and PFOS? Understanding Forever Chemicals
PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid) are synthetic chemicals that have been manufactured and used in industrial applications for decades. They're part of a larger family of chemicals called PFAS (per- and polyfluoroalkyl substances), but PFOA and PFOS are the most studied and most commonly detected in drinking water.
These chemicals earned the nickname "forever chemicals" because of their remarkable stability. The carbon-fluorine bonds that make up their structure are extremely strong and don't break down through normal environmental processes like sunlight, heat, or microbial degradation. This means once PFOA and PFOS enter the environment or your body, they stay there essentially forever.
Why Were PFOA and PFOS Created?
PFOA and PFOS were developed for their water-repellent and stain-resistant properties. They've been used in the manufacturing of non-stick cookware (like Teflon), food packaging, firefighting foams, textile treatments, and various industrial processes. For decades, manufacturers valued these chemicals precisely because they don't break down, not realizing this persistence would become a major public health concern.
EPA's 2023 Drinking Water Standards: What Changed
In June 2023, the EPA proposed enforceable Maximum Contaminant Levels (MCLs) for PFOA and PFOS in drinking water. This was a watershed moment in drinking water regulation. Here's what you need to know about these new standards.
The New MCL Values
Under the EPA's 2023 proposal, the combined MCL for PFOA and PFOS was set at 4 parts per trillion (ppt). This means drinking water systems would be required to keep combined PFOA and PFOS levels below 4 ppt. To put this in perspective, 4 ppt is an extraordinarily small amount, equivalent to one drop of water in an Olympic swimming pool. The EPA chose this level based on extensive health research and risk assessment.
It's important to note that for many decades, there was no federal drinking water standard for these chemicals at all. Some states and local water systems had set their own limits before 2023, but this EPA action created the first nationwide standard. The finalization of these rules means that water utilities across the country have been working to monitor compliance and, where necessary, implement treatment systems to bring their water into compliance.
Why Such a Low Limit?
The EPA didn't choose 4 ppt arbitrarily. The agency based this limit on peer-reviewed scientific studies showing health effects at low exposure levels. The goal of an MCL is to protect public health with an adequate margin of safety, considering the most vulnerable populations like infants, children, and pregnant women.
Health Effects of PFOA and PFOS Exposure
Scientific evidence has accumulated over the past two decades linking PFOA and PFOS to a range of serious health problems. Understanding these risks helps explain why the EPA took action on these chemicals.
Thyroid Disease
One of the most consistently documented health effects of PFOA and PFOS exposure is thyroid dysfunction. Multiple epidemiological studies have found associations between elevated PFOA and PFOS levels in blood and thyroid disease, particularly hypothyroidism (underactive thyroid). The thyroid gland is crucial for metabolism, growth, and development, making thyroid health especially important for children and pregnant women.
Liver Damage
The liver is a major target organ for PFOA and PFOS toxicity. Studies in both animals and humans have documented liver enlargement, elevated liver enzymes (indicating liver stress), and changes in cholesterol metabolism. Because the liver is responsible for detoxifying your body, damage to this organ can have cascading health effects.
Immune System Suppression
Research has shown that PFOA and PFOS can suppress immune function, reducing the effectiveness of vaccinations and lowering resistance to infections. This effect appears to be dose-dependent, meaning higher exposures cause greater immune suppression. For children whose immune systems are still developing, this is a particular concern.
Other Health Concerns
Emerging research has also linked PFOA and PFOS to elevated cholesterol levels, kidney disease, testicular and kidney cancer, and thyroid cancer. Pregnant women who are exposed may face increased risks of pregnancy-induced hypertension and gestational diabetes. While not all of these associations have been definitively proven in humans, the animal evidence is substantial, and several have been confirmed in occupational exposure studies.
Vulnerable Populations
Children are generally more vulnerable to toxic exposures than adults because their organs are still developing and they have longer lifespans ahead during which health effects can manifest. Pregnant women are also at higher risk because PFOA and PFOS can cross the placenta and expose the developing fetus. Nursing infants may also be exposed through breast milk.
Where Is PFOA and PFOS Contamination Highest?
PFOA and PFOS contamination is not evenly distributed across the United States. Certain regions have significantly higher levels due to industrial activity, military installations, or airports where aqueous film-forming foams (AFFF) were used.
High-Risk Regions and Industries
Areas with the highest documented contamination include regions with fluorochemical manufacturing plants, military bases, airports, and firefighter training facilities. States like New Jersey, North Carolina, Pennsylvania, and Ohio have documented some of the highest levels in the nation, though PFOA and PFOS have been detected in low levels in virtually every state.
Industrial sites where non-stick cookware and other products were manufactured are often surrounded by contaminated groundwater. Military bases and airports present a different contamination pathway, primarily through the historical use of AFFF for aircraft and vehicle fire suppression training exercises. These foams are extremely effective at extinguishing fuel fires but contain high concentrations of PFOA and PFOS.
How Contamination Reaches Drinking Water
PFOA and PFOS contaminate drinking water primarily through groundwater. Because these chemicals are highly soluble in water and extremely persistent, once they enter groundwater they migrate toward and into drinking water wells. Surface water contamination is less common but does occur in areas near manufacturing sites or landfills.
If you live near a known contamination source (military base, industrial facility, or airport), your risk is higher. However, you cannot determine your exposure risk simply by location. The best way to know if your water is contaminated is to test it. ClearWater's free ZIP code lookup tool can help you find EPA water quality data for your area and see if PFOA or PFOS has been detected in your local water supply.
How to Test Your Drinking Water for PFOA and PFOS
Testing is the only way to know whether PFOA and PFOS are present in your drinking water. There are several testing options available to homeowners.
Check Your Water Utility Report
Every public water system in the United States is required to provide consumers with an annual Water Quality Report (also called a Consumer Confidence Report). This report lists contaminants detected in the water supply during the previous year. Contact your local water utility and request this report, or look for it on their website. Check to see if PFOA or PFOS are listed, and if so, what levels were detected.
Use ClearWater to Check Your Area
Enter your ZIP code into ClearWater to access EPA water quality data for your region. This gives you a broader picture of whether PFOA and PFOS contamination has been documented in your area, which can help inform your decision about whether private testing is warranted.
Get Private Lab Testing
If you want to test your specific water source (well water or tap water), you can arrange testing through a certified laboratory. Contact your state's drinking water program to find certified labs in your area. Testing typically costs between $300 and $500 for a comprehensive PFAS panel that includes PFOA and PFOS. If you have a private well, testing is especially important since private wells are not regulated by the EPA and are not required to test for PFOA and PFOS.
PFOA and PFOS Removal Methods for Your Home
If testing shows that PFOA and PFOS are present in your drinking water above the EPA's 4 ppt standard, several treatment options are available. The most effective removal methods are described below.
Activated Carbon Filtration
Activated carbon is one of the most commonly used treatments for removing PFOA and PFOS from drinking water. Activated carbon works by adsorption, a process where contaminant molecules attach to the surface of the carbon material. When water passes through an activated carbon filter, PFOA and PFOS molecules stick to the carbon, and cleaner water comes out the other side.
Activated carbon filters come in several forms: pitcher filters, faucet-mounted filters, undersink filters, and whole-house systems. For PFOA and PFOS specifically, undersink or whole-house systems are more effective than pitcher filters because they have more contact time with the water and a larger volume of carbon.
The main limitation of activated carbon is that it eventually becomes saturated. Once the carbon is full of contaminants, it can no longer remove PFOA and PFOS effectively. Filter cartridges must be replaced according to the manufacturer's recommendations, which depend on water flow rate and contaminant concentration. In areas with high PFOA and PFOS levels, cartridges may need replacement every 6 to 12 months.
Ion Exchange Resins
Ion exchange is another proven method for removing PFOA and PFOS. This technology uses special resin beads that attract and bind to contaminants based on electrical charge. PFOA and PFOS, which carry a negative charge, are attracted to positively charged sites on the resin.
Ion exchange systems are often used in point-of-use filters (undersink or countertop) or whole-house systems. Like activated carbon, ion exchange resins eventually become saturated and need to be replaced or regenerated. In commercial applications, resins can sometimes be regenerated with salt solutions, though this is less common in home systems.
Reverse Osmosis
Reverse osmosis (RO) systems force water through a semi-permeable membrane that blocks most contaminants, including PFOA and PFOS. RO is highly effective at removing a broad range of contaminants, but it has some drawbacks. RO systems waste water (typically 3 to 4 gallons of water are wasted for every gallon of clean water produced), and they also remove beneficial minerals from water. RO systems are typically used as point-of-use treatments (undersink or countertop) rather than whole-house systems.
Whole-House Systems vs. Point-of-Use Treatment
Whole-house treatment systems remove PFOA and PFOS from all water entering your home, which means clean water at every tap. These systems are more expensive to install and maintain but provide comprehensive protection. Point-of-use systems (undersink filters, pitcher filters, or faucet-mounted filters) treat only the water from a specific tap, usually in the kitchen. They're less expensive but require that you use that specific tap for drinking and cooking water.
For families with young children or pregnant women, a whole-house system or at minimum a dedicated undersink filter for drinking and cooking water is recommended. This ensures that exposure is minimized across multiple water use scenarios.
Maintenance and Certification
When selecting a treatment system, look for products certified by NSF International or the Water Quality Association (WQA) specifically for PFOA and PFOS removal. Certification ensures that the system has been tested and proven effective. Whatever system you choose, follow the manufacturer's maintenance schedule for filter or resin replacement. An undersized or saturated filter provides a false sense of security and may not actually remove contaminants.
What If You Have a Private Well?
Private well owners face particular challenges with PFOA and PFOS because wells are not regulated by the EPA and are not routinely tested for these chemicals. If you have a private well, especially if you live near a known contamination source, testing is essential.
Well water testing for PFOA and PFOS should be conducted by a certified laboratory. After testing, if contamination is found, point-of-use treatment (such as an undersink filter with activated carbon or ion exchange) is the most practical solution for most homeowners. Some well owners have installed whole-house treatment systems, but these are more expensive and require regular maintenance.
Actions You Can Take Today
If you're concerned about PFOA and PFOS in your drinking water, here are concrete steps to take right now:
- Contact your water utility and request the most recent annual Water Quality Report. Ask specifically whether PFOA or PFOS have been detected and at what levels.
- Check whether your area has a known contamination source. If you live within a few miles of a military base, airport, or industrial facility, your risk is elevated.
- Use ClearWater's free ZIP code lookup to see what EPA water quality data has been reported for your region.
- If your water utility detected PFOA or PFOS, or if you have a private well, arrange professional testing through a certified laboratory in your state.
- If testing shows contamination above 4 ppt, install a treatment system rated for PFOA and PFOS removal. Start with point-of-use treatment (undersink or pitcher filter) if budget is a concern, but consider whole-house treatment if you have young children or pregnant household members.
- After installing a filter, set a reminder to replace cartridges or resins on schedule. A saturated filter loses effectiveness.
- If you rent your home, contact your landlord and local health department to discuss testing and treatment options. Tenants have a right to safe drinking water.
The Bottom Line on PFOA and PFOS
PFOA and PFOS are serious drinking water contaminants that have persisted in the environment for decades and accumulated in water supplies across the country. The EPA's 2023 drinking water standard reflects the scientific evidence linking these chemicals to thyroid disease, liver damage, immune suppression, and other health effects. The good news is that effective removal technologies are available, and testing is straightforward and affordable.
The most important step is to find out whether your water is contaminated. Once you know your water quality status, you can make informed decisions about treatment. Whether through your water utility's actions or your own home treatment system, protecting your family from PFOA and PFOS is possible. Start by checking your water quality today.