PFAS in Drinking Water: What Are "Forever Chemicals" and How to Protect Your Family

PFAS, short for per- and polyfluoroalkyl substances, have transitioned from an obscure industrial term to a major national health concern. These "forever chemicals" are now detected in the drinking water of millions of Americans, prompting the EPA to issue historic new safety regulations in 2024 and 2025.

What Are PFAS? The Science Behind "Forever Chemicals"

PFAS are a family of thousands of synthetic chemicals that have been used in consumer and industrial products since the 1940s. Their unique chemical structure—specifically the carbon-fluorine bond—is one of the strongest in organic chemistry. This bond is what makes PFAS so effective at repelling heat, water, and oil.

However, that same strength is their greatest flaw when it comes to the environment. Because these bonds are so difficult to break, PFAS do not degrade naturally. They persist in the soil and water for decades, and when ingested, they accumulate in the human body, particularly in the blood, liver, and kidneys. This persistence has earned them the nickname "forever chemicals."

The most well-known and studied PFAS are PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate). While these specific chemicals have been largely phased out of manufacturing in the United States, they remain in the environment and have been replaced by thousands of other "short-chain" PFAS, such as GenX, which are now being found to have similar persistence and toxicity profiles.

How Does PFAS Get Into Drinking Water?

PFAS enter our water supply through a variety of pathways, often originating from industrial sites, military bases, and airports. Because PFAS were used extensively in aqueous film-forming foams (AFFF) for firefighting, areas near training sites often have significant groundwater contamination.

Industrial discharge is another major source. Manufacturing plants that produced non-stick cookware, waterproof clothing, and stain-resistant carpets often released PFAS-laden wastewater into local rivers or onto the ground, where it leached into aquifers. Once in the water, PFAS are highly mobile; they don't stick to soil particles well, allowing them to travel long distances from the original source.

Landfills also play a role. When products containing PFAS—like discarded fast-food wrappers, old carpets, or treated upholstery—begin to break down, the PFAS can leach into the landfill's wastewater (leachate). If not properly treated, this leachate can contaminate nearby water sources. Conventional wastewater treatment plants are generally not equipped to remove PFAS, meaning these chemicals often pass right through the treatment process and are discharged back into the environment.

Health Risks: What the EPA and CDC Say

The health implications of long-term PFAS exposure are serious and well-documented. According to the EPA and the CDC's Agency for Toxic Substances and Disease Registry (ATSDR), exposure to even minute amounts of certain PFAS can lead to adverse health outcomes.

Key health concerns include:

• Developmental Effects: Exposure during pregnancy or during breastfeeding can lead to low birth weight, accelerated puberty, and bone variations in infants and children.
• Cancer Risk: There is strong evidence linking PFOA to kidney and testicular cancer. The International Agency for Research on Cancer (IARC) recently classified PFOA as "carcinogenic to humans."
• Immune System Suppression: PFAS can interfere with the body's ability to fight infections and may reduce the effectiveness of vaccines.
• Hormonal Disruption: PFAS are known endocrine disruptors, affecting thyroid function and interfering with natural hormones.
• Liver and Cholesterol Issues: High levels of PFAS are consistently associated with increased total cholesterol and LDL ("bad") cholesterol, as well as changes in liver enzymes.

The 2024 EPA PFAS Standard — What Changed

In April 2024, the EPA finalized the first-ever National Primary Drinking Water Regulation (NPDWR) for six PFAS. This was a landmark moment in environmental policy, as it marked the first time the federal government set legally enforceable limits for these chemicals.

The new standards set the Maximum Contaminant Levels (MCLs) at:

• PFOA: 4.0 parts per trillion (ppt)
• PFOS: 4.0 parts per trillion (ppt)
• PFNA, PFHxS, and HFPO-DA (GenX): 10 ppt each

To put "4 parts per trillion" in perspective, it is equivalent to one drop of water in 20 Olympic-sized swimming pools. The EPA's decision to set the limit so low reflects the scientific consensus that there is virtually no safe level of exposure to PFOA and PFOS.

Under this new rule, public water systems must complete initial monitoring by 2027 and provide the public with information about the levels of these PFAS in their drinking water. If levels exceed the MCLs, the systems must implement solutions to reduce PFAS by 2029.

Which US Cities Have the Highest PFAS Levels?

While PFAS contamination is a national issue, certain regions have seen significantly higher concentrations due to their industrial history or proximity to military installations. Recent data indicates that "hotspots" exist in several states.

Cities in North Carolina, particularly those along the Cape Fear River, have struggled with GenX contamination for years. Parts of New Jersey, Michigan, and Pennsylvania have also reported high levels due to historical manufacturing. In the West, cities near large military bases in Colorado and California have seen significant groundwater impacts.

You can use WaterQ to search for your city and see if your local water utility has reported PFAS testing results. It is important to note that many systems are only now beginning the rigorous testing required by the new EPA standards, so a lack of reported data does not necessarily mean your water is PFAS-free.

How to Test Your Home Water for PFAS

If you are concerned about your water, especially if you rely on a private well, testing is the only way to know for sure. PFAS are colorless, tasteless, and odorless, so they cannot be detected by human senses.

For residents on municipal water, start by checking your annual water quality report, also known as a Consumer Confidence Report (CCR). If your utility hasn't tested for PFAS yet, you may want to conduct your own test.

Professional Lab Testing: This is the most accurate method. You should use a laboratory that is certified to perform EPA Method 533 or 537.1. These labs will send you a sterile collection kit with specific instructions to avoid cross-contamination (as many common household items contain PFAS).

DIY Test Kits: While some mail-in DIY kits exist, ensure they use an accredited lab for analysis. Simple "color-change" strips available at hardware stores are generally not sensitive enough to detect PFAS at the low parts-per-trillion levels that matter for health.

Water Filters That Remove PFAS

Not all water filters are created equal when it comes to "forever chemicals." Standard pitcher filters designed for taste and odor (like basic Brita filters) are often ineffective at removing PFAS.

The two most effective technologies for home PFAS removal are:

1. Activated Carbon (Granular or Block): These filters use a bed of carbon to "adsorb" the PFAS chemicals. For maximum effectiveness, look for "dual-stage" or "under-sink" systems that allow for more contact time between the water and the carbon. Ensure the filter is certified to NSF/ANSI Standard 53 for PFAS reduction.
2. Reverse Osmosis (RO): RO systems force water through a semi-permeable membrane that blocks the large PFAS molecules. These are highly effective and are often installed under the kitchen sink for drinking and cooking water. Look for NSF/ANSI Standard 58 certification.

Regardless of the system you choose, maintenance is critical. Once a filter reaches its capacity, it can no longer trap contaminants and may even begin to release them back into your water. Always follow the manufacturer's schedule for filter replacement. You can learn more about filtration in our contaminant guide.

What to Do if Your City Has PFAS Violations

If your water system reports an exceedance of the new EPA standards, the utility is required to notify the public. Here is how to respond:

• Read the Notice Carefully: The notice will explain the levels detected and what the utility is doing to address the problem.
• Use Filtered Water for High-Risk Individuals: If you have infants, are pregnant, or have a compromised immune system, switch to a certified filter or bottled water for drinking and preparing formula immediately.
• Contact Your Local Officials: Public pressure is often the fastest way to accelerate infrastructure improvements. Ask your city council and water board about their timeline for installing PFAS-removal technology.
• Understand the Scope: Check our scoring methodology to see how PFAS violations impact a city's overall water grade.

Data sources: Environmental Protection Agency (EPA) 2024 NPDWR Guidelines, CDC Agency for Toxic Substances and Disease Registry (ATSDR), and WaterQ National Compliance Database.