PFAS in Well Water: Sources, EPA Limits, Testing and Filters (2026)
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- PFAS are “forever chemicals” from firefighting foam, nonstick and waterproof products and some factories. They do not break down and can soak into groundwater.
- The EPA limit for PFOA and PFOS in public water is 4 parts per trillion. Private wells are not regulated, so testing is up to you.
- Boiling does not remove PFAS. Reverse osmosis and activated carbon filters certified for PFAS do.
- Use the checker below to see your risk or read your lab results.
If you live near an airport, a military base or a factory, you may have heard about PFAS turning up in local wells. These chemicals are tasteless, odorless and invisible, so a lab test is the only way to know.
This guide explains what PFAS are, how they get into wells, the current EPA limits, how to test and which filters actually remove them.
PFAS risk and result checker
PFAS risk and result checker
Tick what is near your well. If you already have a lab report, enter the PFOA and PFOS results in parts per trillion (ppt or ng/L).
What are PFAS?
PFAS (per and polyfluoroalkyl substances) are a family of thousands of man made chemicals used since the 1940s. They make products resist heat, water, oil and stains.
The best known are PFOA and PFOS. Because the carbon fluorine bond is one of the strongest in chemistry, PFAS barely break down in the environment or the body, which is why they are called forever chemicals.
Long term exposure has been linked to some cancers, high cholesterol, liver effects, lower response to vaccines and low birth weight, according to the EPA.
How PFAS get into private wells
- Firefighting foam (AFFF). Used at airports, military bases and fire training sites. It is one of the biggest sources of PFAS in groundwater.
- Industrial sites. Plants that made or used nonstick coatings, waterproof fabrics, plating or paper products.
- Landfills. Liquid that drains from waste can carry PFAS into nearby aquifers.
- Biosolids. Treated sewage sludge spread on farm fields can contain PFAS.
- Septic systems. Household products can add small amounts close to shallow wells.
Shallow wells in sand and gravel are usually at higher risk than deep wells in rock, but PFAS have been found in deep wells too.
EPA PFAS limits in 2026
In 2024 the EPA set the first federal limits for PFAS in drinking water. They apply to public water systems, not private wells, but they are the best yardstick for your test results.
| Chemical | EPA limit (public water) | Status in 2026 |
|---|---|---|
| PFOA | 4 parts per trillion | Limit stays; EPA proposed moving the compliance deadline from 2029 to 2031 |
| PFOS | 4 parts per trillion | Same as PFOA |
| PFHxS, PFNA, GenX and PFAS mixtures | 10 ppt and a hazard index | EPA proposed removing these limits in May 2026; not final |
Sources: EPA PFAS drinking water rule; Ballard Spahr, June 2026. Several states set their own limits, so check your state too.
Four parts per trillion is tiny: about four drops in 20 Olympic swimming pools. That is why a careful lab method matters.
How to test your well for PFAS
- Use a state certified lab. Ask for EPA Method 533 or 537.1, which cover PFOA, PFOS and other common PFAS.
- Follow the sampling kit exactly. PFAS are in many everyday items, so labs ask you to avoid nonstick gloves, some sunscreens and waterproof clothing while sampling.
- Sample before any filter. Take the sample from a tap before treatment so you know what is in the well itself.
- Ask your state first. Many states offer reduced cost or no cost PFAS testing for wells near known sources.
Home test strips for PFAS are not reliable at parts per trillion levels. For other contaminants, our well water test kits guide covers home and lab options.
If you are already testing for bacteria and nitrate each year, add PFAS once and then every few years. See how often to test well water.
How to remove PFAS from well water
Reverse osmosis at the kitchen tap
Under sink reverse osmosis removes most PFAS from drinking and cooking water. Look for certification to NSF/ANSI 58 with a PFAS reduction claim.
It is the most affordable option for most homes. See our under sink reverse osmosis picks.
See PFAS certified RO systems on Amazon
Activated carbon filters
Granular activated carbon (GAC) and carbon block filters remove PFOA and PFOS well when they are sized correctly and changed on time. Look for NSF/ANSI 53 with a PFAS claim for point of use filters.
Whole house carbon systems treat every tap and are often what state programs install. Our whole house filter guide covers sizing.
What does not work
- Boiling. It does not remove PFAS and can concentrate them as water evaporates.
- Water softeners. They target hardness minerals, not PFAS.
- Basic pitcher filters. Most are not certified for PFAS unless the label says so.
| Option | Treats | Notes |
|---|---|---|
| Reverse osmosis (one tap) | Drinking and cooking water | Look for NSF/ANSI 58 PFAS claim |
| Carbon block filter (one tap) | Drinking and cooking water | Look for NSF/ANSI 53 PFAS claim; change cartridges on schedule |
| Whole house carbon (GAC) | Every tap | Size to your flow rate; test after install |
| Bottled water | Short term | Use while you arrange treatment |
Related: Radon in well water: what your test result means, with a result checker and treatment options.
Frequently asked questions
What is a safe level of PFAS in well water?
The EPA limit for public water is 4 parts per trillion for PFOA and for PFOS, and its health goal is zero. Private wells are not regulated, so many homeowners use 4 ppt as their target.
Does boiling water remove PFAS?
No. Boiling does not destroy PFAS and can slightly concentrate them as water evaporates.
Does a reverse osmosis system remove PFAS?
Yes, a reverse osmosis system certified to NSF/ANSI 58 for PFAS removes most PFOA and PFOS from drinking water at the tap where it is installed.
How much does a PFAS water test cost?
Lab tests for PFAS cost more than standard well tests, usually a few hundred dollars. Check with your state health or environment agency first, since some offer reduced cost testing.
Can PFAS get into a deep well?
Yes. Deep wells are generally at lower risk than shallow ones, but PFAS have been found in deep wells near major sources such as firefighting foam sites.
