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PFAS filters: activated carbon, reverse osmosis, pitchers. What actually works

Published 19 September 2026 · pfasnearme

Almost every filter sold in France says something about chlorine, limescale or taste. Very few say anything verifiable about PFAS. This guide starts from the independent tests that exist, says what each type of filter actually removes, and ends with a simple rule based on your commune's number.

What a single study taught us

In 2020, researchers from Duke and NC State did something nobody had done. They went into 73 homes in North Carolina and sampled water before and after the filter the residents actually used. 76 point-of-use filters, 13 whole-house systems, pitchers, fridge filters, under-sink filters, reverse osmosis units [1][2].

The result fits in three lines. Every under-sink reverse osmosis unit and every two-stage under-sink filter removed more than 94% of PFAS, GenX included. Activated carbon filters, in whatever form, removed 73% on average, but some removed everything and others nothing. And four of the eight whole-house systems returned water with more PFAS than went in [1][2].

Activated carbon also has a specific weakness. It holds long-chain PFAS, PFOA and PFOS, better, around 60 to 70%, than short chains, around 40% [1]. And short chains are exactly what is replacing the old banned molecules.

The filter types, one by one

Prices are orders of magnitude observed in 2026 and the EPA gives the same spread, from 20 to more than 1,000 dollars [7]. We sell no filters. Our filter comparison carries affiliate links labelled as such; this guide carries none.

Pitchers, in detail

This is the filter people buy first, so it deserves the detail. A Canadian study in 2024 ran 160 litres of tap water through five pitchers while tracking 75 PFAS. With Montreal water, ZeroWater removed close to 100%, Clearly Filtered 96%, Aquagear 60%, Brita Elite 48% and Brita Standard 38%. With another water, richer in anions, Brita Elite fell to 20% [3].

The US non-profit EWG tested ten pitchers in a real home. ZeroWater, Clearly Filtered and Berkey removed 100% of the 25 PFAS tracked, PUR 79%, standard Brita 66%, Brita Elite 22% [4]. The two tests agree on the essentials. Ion exchange pitchers work. Carbon-only pitchers half work, and less well when the water is hard.

The trade-off with resins is exhaustion. In the Canadian test, ZeroWater released dissolved solids and dropped the pH after 80 litres in the more loaded water [3]. A cartridge of that type lasts ten to twenty days for a family. The yearly cost quickly overtakes a reverse osmosis unit.

How to read a certification

In France there is no public label for PFAS reduction. The attestation de conformité sanitaire, the ACS, says a material does not leach anything dangerous into the water. It says nothing about what the filter removes. The only independent proof available today is American.

Two standards matter. NSF/ANSI 53 for carbon and resin filters, NSF/ANSI 58 for reverse osmosis [5][6]. Careful, a filter can be certified to NSF/ANSI 53 for lead or chlorine without being certified for PFAS. Look for the explicit words "PFOA/PFOS reduction" or "total PFAS reduction" on the box, or the exact model in the NSF directory [9].

And know what the certification proves. To earn the PFAS claim, a filter must bring water below 20 ng/L [5]. The US EPA itself writes that current certifications do not guarantee reaching its own 4 ng/L limits [6]. Our 0.5 ng/L benchmark is lower still. So a certified pitcher cuts exposure hard, but nobody can promise you a precise number at the tap.

The three mistakes that cancel everything

The first is the cartridge kept too long. Activated carbon works by adsorption. Once saturated it holds nothing back, and it can release what it has fixed. The Duke authors found no link between brand, filter age and performance, which means you cannot tell by eye when a filter has given up [2]. Change at the prescribed interval [7][8].

The second is boiling. PFAS do not evaporate at 100 °C. Boiling reduces the volume and slightly concentrates the rest [5].

The third is the whole-house system bought for PFAS. As we saw, it gave the worst results. On top of that it removes the residual chlorine and leaves the house pipes open to bacterial growth [2]. Filter at the tap you drink from, not at the entry to the house.

Our simple rule, by your number

Look up your city on this site, read the sum of 4 PFAS, then apply this.

• Below 0.5 ng/L, or not detected by a good laboratory. No filter needed for PFAS.
• Between 0.5 and 4 ng/L. A resin or carbon pitcher certified to NSF/ANSI 53 for PFAS, cartridge changed on time. For infant formula, prefer reverse osmosis.
• Between 4 and 20 ng/L. Under-sink reverse osmosis, or a certified two-stage under-sink filter. A pitcher is a stopgap.
• Above 20 ng/L, the HCSP vigilance value [10]. Reverse osmosis, no debate, and read what to do when your commune is above the benchmark.

A word on reverse osmosis. It produces very demineralised water, which is not a problem for an adult who eats normally. For infant formula, the powder already contains the minerals needed. And it sends several litres to the drain per litre filtered. That is a real cost, but far smaller than bottled water over years.

Why this guide exists

The water supplier has a legal duty to deliver water below 100 ng/L. It has no duty below that number. The gap between 100 and 0.5 ng/L is closed by you, or by nobody. A well-chosen filter does it for a few euros a month. A badly chosen one only reassures.

Frequently asked questions

Does a Brita pitcher remove PFAS?

Partly, and unpredictably. In independent tests, standard activated carbon pitchers remove between 20 and 70% of PFAS depending on the model, the water and the age of the cartridge. Ion exchange pitchers such as ZeroWater reach 99% but their cartridges run out fast. Check whether the exact model carries an NSF/ANSI 53 certification for PFAS reduction.

Is reverse osmosis really the best PFAS filter?

Yes, on the available data. In the only study done in real homes, every under-sink reverse osmosis system removed more than 94% of PFAS, short and long chains included. The price is a system to install, several litres of waste water per litre produced, and very demineralised water.

Do I need a whole-house filter?

No, not for PFAS. Exposure comes from what you drink and cook with, not from the shower. Whole-house activated carbon systems gave the worst results of the North Carolina study. Four of eight returned water with more PFAS than went in.

How often should I change the cartridge?

At the manufacturer's interval, never later. Saturated activated carbon holds nothing back and can release what it has accumulated. If your water is hard or rich in organic matter, the cartridge saturates faster.

Does an NSF certified filter guarantee I am below 0.5 ng/L?

No. NSF/ANSI 53 certification for PFAS requires getting below 20 ng/L, not below 4 or 0.5. The US EPA says so itself. This site's benchmark is far lower than what a certification proves. That is one reason we recommend reverse osmosis as soon as water is above 20 ng/L.

Sources

1. Herkert et al. (2020), Environmental Science & Technology Letters 7(3): Assessing the effectiveness of point-of-use residential drinking water filters for PFAS (76 point-of-use and 13 whole-house filters, North Carolina)
2. Duke University, Nicholas School (2020): Not all in-home drinking water filters completely remove toxic PFAS (summary of the study by its authors)
3. Frontiers in Environmental Chemistry (2024): Performance of pitcher-type POU filters for the removal of 75 PFAS from drinking water, comparing different water sources
4. Environmental Working Group: Getting forever chemicals out of drinking water, EWG's guide to PFAS water filters (household test of ten pitchers)
5. NSF: PFAS in drinking water (NSF/ANSI 53 and 58, PFAS reduction claim requires below 20 ppt, boiling does not remove PFAS)
6. US EPA: Identifying drinking water filters certified to reduce PFAS (certification standards do not yet match the 4 ppt federal limits)
7. US EPA: Reducing PFAS in your drinking water with a home filter (types, cost range, maintenance)
8. Michigan Department of Health and Human Services: Certified PFAS-reducing filters (fact sheet, maintenance)
9. NSF certified product listings: drinking water treatment units, PFOA/PFOS reduction
10. HCSP (9 July 2024): avis PFAS dans les EDCH (20 ng/L for the sum of four PFAS)

All sources retrieved September 2026. The full method is on the methodology page. The synthesis was prepared with the help of an AI and then checked against the primary sources.