PFAS

At a glance: PFAS are a large family of long-lasting industrial chemicals, and EPA’s current limit for the two best studied, PFOA and PFOS, is 4 parts per trillion each. You cannot see, smell or taste them, so the only way to know is data: your utility’s results or a lab test of your well. If you have them, a reverse osmosis or carbon filter certified for PFAS reduction at the kitchen tap is the most cost-effective fix for most homes.

Start with the numbers for your own water on our PFAS lookup, which covers every system in EPA’s latest national sampling.

What it is and where it comes from

PFAS (per- and polyfluoroalkyl substances) are thousands of related chemicals used in consumer, commercial and industrial products. EPA describes them as long-lasting chemicals that break down very slowly, which is why many are found in the blood of people and animals worldwide.

EPA’s health table lists discharge from manufacturing and industrial chemical facilities as the typical source of PFOA and PFOS in drinking water. For wells, Connecticut’s environmental agency points to nearby sources such as sites where firefighting foam was used, landfills and factories that used PFAS.

PFAS are common in public water. EPA’s UCMR 5 sampling, with final data released in August 2026, covered 10,313 water systems. About 35% had at least one PFAS detected, and 1,165 averaged above an EPA limit at a sampling point, serving roughly 55 million people. See results by state.

Health and household effects

EPA’s health table links PFOA and PFOS to cardiovascular, immune and liver effects and increased cancer incidence, which is why their health goal is zero. ATSDR lists health effects associated with PFAS exposure as:

• Higher cholesterol levels
• Changes in liver enzymes
• Small decreases in birth weight
• Lower antibody response to some vaccines
• Pregnancy-induced high blood pressure and preeclampsia
• Kidney and testicular cancer (associated with PFOA)

Risk depends on how much you are exposed to and for how long. Drinking and cooking are what count. EPA says only a small amount of PFAS gets into the body through the skin, so showering, bathing and washing dishes “are unlikely to significantly increase your risk.”

PFAS have no household effects you would notice. They do not stain, smell or change taste.

Limits and what they mean

Compound	EPA limit (2024 rule)	Status in September 2026
PFOA	4 ppt	Kept in the May 2026 proposal; deadline would move from 2029 to 2031
PFOS	4 ppt	Same as PFOA
PFHxS	10 ppt	Proposed for removal
PFNA	10 ppt	Proposed for removal
GenX (HFPO-DA)	10 ppt	Proposed for removal
Mixtures of PFHxS, PFNA, GenX and PFBS	Hazard index of 1	Proposed for removal

EPA proposed the rescission and the deadline extension on May 18, 2026, and the comment period closed July 20, 2026. Until EPA finalizes the changes, the 2024 limits are the law, and utilities must finish initial monitoring by 2027. One part per trillion is one nanogram per liter.

WHO has not set a final PFAS guideline value. It says PFAS will be part of the evidence reviews for the fifth edition of its drinking water guidelines.

How to test

City water. Your utility’s results from EPA’s UCMR 5 sampling are on our PFAS lookup, by ZIP code, including which compounds were found. Your annual Consumer Confidence Report may also list PFAS results.

Private well. Nobody has sampled it for you. Use a state-certified lab. Connecticut’s environmental agency says a PFAS test typically costs $300 or more per sample, recommends EPA Method 533 because it covers more compounds, and expects results in two to three weeks. Its advice is to test mainly if a known or suspected PFAS source is nearby. Our well testing guide covers how to order one.

No home test strip can measure PFAS at parts-per-trillion levels.

Treatment options

Method	How well it works	Certification to look for	Cost range
Reverse osmosis, under-sink or countertop	High, including short-chain PFAS	NSF/ANSI 58 with a PFOA/PFOS claim	$475 to $1,999 (systems we track)
Activated carbon, point of use	High for PFOA and PFOS; weaker on short chains	NSF/ANSI 53, PFOA/PFOS or total PFAS	$10 to $100
Activated carbon, whole house	High for long chains when certified	NSF/ANSI 53 system listing	$1,554 to $2,099 for certified systems we track
PFAS-selective resin (specialty media)	High capacity	NSF/ANSI 53	Few home systems; get a quote
Softener, sediment filter, UV or boiling	Not effective	None	Not applicable

Point-of-use costs are Minnesota Department of Health estimates based on 2017 and 2018 quotes; rows marked “systems we track” are prices checked September 2026.

Certification is where marketing gets slippery. A system certified to NSF/ANSI 53 or 58 for PFOA and PFOS has been tested as a finished product. “Tested to NSF standards” or “uses certified media” is not the same thing. NSF/ANSI 53 also has a newer total PFAS claim that covers more compounds. Our PFAS removal guide explains each standard, and the filter finder shows which products hold which claims.

You may not need a whole-house system. Because exposure is mainly through drinking, the Minnesota Department of Health says point-of-use treatment tends to be more economical. Compare the two approaches in whole-house filter vs reverse osmosis, and see our PFAS filter picks if you still want whole-house treatment.

When to call a professional

If a well test shows PFAS above EPA’s limits, call your state health or environmental agency first. It can tell you whether other wells nearby have been tested and what help is available where you live.

Hire a licensed plumber or water treatment professional for whole-house systems, and ask for the certification listing by standard and compound, not just a brochure claim. After any treatment is installed, retest the treated water to confirm it works, and replace filters on the maker’s schedule, sooner if your water has short-chain PFAS.