Blog: PFAS in drinking water, explained
Longer reads on how we read the data, where our benchmark comes from, and what the numbers mean for your tap water.
Guides
Practical pieces linked from every result page. What to do about an exceedance, which filters work, how to read a result.
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PFAS filters: activated carbon, reverse osmosis, pitchers. What actually works
The only study that tested filters in real homes found 94% removal for reverse osmosis and wildly variable results for activated carbon. What that means for what you buy.
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PFAS in tap water: what to do if your city is above the benchmark
Which threshold is exceeded, who should act first, what actually works and what does not, and which questions to ask your mairie and the ARS.
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Bottled water and PFAS: is it actually better than tap water?
Que Choisir found PFAS in 21 of 32 bottled waters in 2026. What the tests show, when bottled water makes sense and when a filter remains the better answer.
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Reading a PFAS result: PFAS-4, sum of 20, detection limit, ng/L and µg/L
What every number on a city page means, why "<0,004" is not zero, and why we only report a trend from three values.
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PFAS drinking water limits around the world: EU 100, Germany 20, Sweden 4, Denmark 2, US 4 ng/L
Every limit in one table, with dates and legal status. And why the same EFSA number turns into 100, 20, 4 or 2 ng/L depending on the country.