PFNA
Perfluorononanoic acid
- EPA federal limit
- 10 ppt
- Detected in
- 10,289 systems
- Exceeds limit in
- 15 systems
What is PFNA?
Perfluoronoanoic acid (PFNA) is a man-made chemical that belongs to the PFAS family, a group of thousands of synthetic chemicals often called "forever chemicals" because they break down very slowly in the environment and in the human body. PFNA is a longer-chain PFAS, meaning it has a larger molecular structure that tends to build up in living things over time. Like other PFAS, it does not naturally occur in nature.
Where does it come from?
PFNA has been used in industrial manufacturing processes and can be found in some consumer products, including stain-resistant coatings on clothing and carpets, grease-resistant food packaging, and certain non-stick cookware. It can also be released into the environment through industrial wastewater and has been detected near manufacturing facilities. Over time, it can move from soil into groundwater and drinking water supplies.
Health concerns
Research on PFNA is still developing, and published data in humans is limited compared to some other PFAS compounds. Animal studies have associated PFNA with effects on the liver, immune system, and hormones, but it is not yet clear how directly those findings apply to people. Some research studies have linked PFNA exposure to changes in thyroid function and developmental effects in children. If you have specific health concerns, consult a healthcare provider.
EPA standard
The EPA set a Maximum Contaminant Level (MCL) of 10 parts per trillion (ppt) for PFNA in drinking water in 2024. An MCL is the highest amount of a contaminant legally allowed in public drinking water. This means water utilities must test for PFNA and take action if levels exceed that limit.
What you can do
If PFNA is detected in your water, consider using a certified reverse osmosis filter or an ion exchange filter, both of which the EPA recognizes as effective at reducing PFAS levels. Granular activated carbon filters may also help but are generally less effective than reverse osmosis. Boiling water does not remove PFAS and should not be used as a solution.
About this summary: Narrative text on this page was drafted by an AI model (claude-sonnet-4-6) from EPA UCMR 5 data and reviewed before publication. The numeric data above is reported by water utilities directly to the EPA. If you spot an error, email data@checkyourwater.org.