My commune is above 0.5 ng/L. Can I still drink the tap water?

Yes, in the vast majority of cases. 0.5 ng/L is our long-term benchmark, not an emergency limit. What changes is that water now uses a noticeable share of EFSA's health budget, especially for a bottle-fed baby. A certified filter fixes the problem at home for a few tens of euros.

At what level does the ARS act?

The legal limit is 100 ng/L for the sum of 20 PFAS. Above it, the ARS asks the supplier for an action plan and can restrict consumption for sensitive groups. Since 2025 it also keeps watch on networks above 20 ng/L for the sum of the four most worrying PFAS, the value recommended by the HCSP.

Should I get a blood test?

In France it is not offered routinely. In the US, the National Academies recommend testing people with a history of elevated exposure and give two serum thresholds, 2 and 20 ng/mL. If you have drunk water above 20 ng/L of PFAS-4 for years, raise it with your doctor.

How long do PFAS stay in the body?

A long time. After exposure stops, blood concentration halves in 2.7 years for PFOA, 3.4 years for PFOS and 5.3 years for PFHxS. So reducing exposure early matters.

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PFAS in tap water: what to do if your city is above the benchmark

Published 13 September 2026 · pfasnearme

Your commune page shows a number above the benchmark. The first question is not "is this dangerous" but "which threshold is exceeded". There are three, and they call for very different responses. This guide takes them in order, then covers what works at home, what does not, and what to ask your mairie.

First, read which threshold is exceeded

Three numbers matter in France, and they do not carry the same weight.

Threshold	Applies to	Status
0.5 ng/L	Sum of 4 PFAS (PFOA, PFOS, PFNA, PFHxS)	Our long-term benchmark, derived from EFSA. Not a standard.
20 ng/L	Sum of 4 PFAS	Provisional threshold recommended by the HCSP in July 2024. The ARS watches networks above it [1][2].
100 ng/L	Sum of 20 PFAS	Legal quality limit, mandatory since January 2026 [3][5].

Between 0.5 and 20 ng/L you are in the zone where the law says nothing and the science says "reduce it if you can". Above 20 ng/L the ARS is looking closely at your network. Above 100 ng/L the water is non-compliant and the supplier has to act. We explain where these numbers come from in our comparison of limits.

One sample above a threshold is not a confirmed situation. The HCSP asks for at least four months of reinforced monitoring across two seasons, with a sample every fortnight, before a non-compliance is confirmed [1]. So look at the history section of your page. Three values above the threshold weigh far more than one.

Then look at who drinks the water in your home

EFSA's health budget is 4.4 ng per kilogram of body weight per week for the four PFAS [8]. A 5 kg bottle-fed baby drinks about 0.75 L of water a day. A 70 kg adult drinks two litres. Per kilo, the baby drinks five times more. The thresholds really matter for that baby.

The Direction générale de la santé instruction of February 2025 says it plainly. If a PFOA or PFOS non-compliance cannot be fixed quickly, consumption restrictions may be imposed "as a priority for sensitive populations", meaning pregnant women, infants and immunocompromised people [2].

So if you prepare infant formula, are pregnant or breastfeeding, and your commune is above 20 ng/L of PFAS-4, act now. Not next week. For the rest of the household, exceeding the 0.5 ng/L benchmark deserves a filter, not worry.

What works at home

Only one study has tested household filters in real homes, in North Carolina, across 76 point-of-use filters. Every reverse osmosis system and every two-stage under-sink filter removed more than 94% of PFAS. Activated carbon filters, the kind in pitchers and fridges, removed 73% on average, but with results ranging from nothing to everything [11].

The practical rule is simple. Up to 20 ng/L, a pitcher certified for PFAS reduction is enough, provided you change the cartridge on time. Above 20 ng/L, or if an infant drinks the water, go for under-sink reverse osmosis. We cover the types, the certifications and the traps in the filter guide.

Bottled water is a reasonable bridge, not a long-term answer. Tests in 2026 found PFAS in 21 of 32 bottled waters. We go through it in the bottled water guide.

What does not work

Boiling water does nothing. PFAS do not evaporate. Boiling reduces the volume of water and slightly concentrates what is left [10]. Sediment filters, water softeners and UV filters do not remove PFAS either. A spent activated carbon filter can even release what it has accumulated. In the North Carolina study, four of eight whole-house systems returned water with more PFAS than went in [11].

What happened elsewhere, and what it teaches you

In Rumilly, Haute-Savoie, the ARS found PFOA at 1.5 times the then-applicable health value of 75 ng/L in August 2022. The contaminated wells were disconnected within three months and two outside sources took over. Three industrial sites were identified, including the Tefal plant next to the well field [6]. Today the Rumilly page shows one of the longest series on this site, and that is because of that crisis.

South of Lyon, downstream of the Arkema-Daikin platform at Pierre-Bénite, around 110 communes have been monitored since 2022. The Ternay well field exceeded 0.1 µg/L. The State ordered Arkema to stop all PFAS by the end of 2024, in steps, and the plant ended 6:2 FTS use in December 2024. In 2024, distribution units such as Givors and Grigny still exceeded the limit on some samples [7].

Two lessons. First, situations get solved mostly by collective decisions, connecting networks, switching wells, treating at the plant. Second, those decisions come when residents ask precise questions. So ask them.

What to ask, and whom

Your mairie or water syndicate is the "person responsible for the production and distribution of water". They have to act. The ARS controls and can impose. These are the questions that move things forward.

Which distribution unit serves my address, and which well field does the water come from?
What PFAS results do you have for this network since 2023, including ones you commissioned yourselves?
Has the ARS qualified the situation as a confirmed non-compliance, or as an alert to be confirmed?
Which PFAS source has been identified upstream, and which administration controls it?
What is the action plan, interconnection, new well or treatment, and by when?
Do you have a recommendation for infants and pregnant women in the meantime?

Since the law of 27 February 2025, PFAS monitoring of drinking water is mandatory and results must be made public [4]. The decree of 22 December 2025 sets the list of 20 PFAS tested from 2026 and adds TFA and 6:2 FTSA from 2027 [3]. So you have the right to these figures, and you will also find them on your commune page here, updated weekly.

Why not to panic, and why not to ignore it

PFAS have no acute effect at these doses. The risk is chronic. EFSA built its budget on a reduced vaccine response in the most exposed children [8]. IARC classified PFOA as carcinogenic to humans in 2023, and PFOS as possibly carcinogenic [9]. These effects build up over years.

And they unwind over years as well. In Ronneby, Sweden, after the switch to clean water, blood concentration halved in 2.7 years for PFOA, 3.4 years for PFOS and 5.3 years for PFHxS [12]. What you do not drink this year still counts in five years. That is the real reason to act early, without drama.

If you have drunk water above 20 ng/L of PFAS-4 for a long time, the US National Academies recommend a blood test and tailored follow-up from 2 ng/mL in serum [13]. In France this test is not offered routinely. Your doctor can prescribe it.

In short

Read which threshold is exceeded and on how many samples. Protect infants and pregnant women first. Filter rather than boil or buy bottles for years. And ask your mairie the six questions above. That is what moved Rumilly and the south of Lyon, and it is what will move your commune.

Frequently asked questions

My commune is above 0.5 ng/L. Can I still drink the tap water?: Yes, in the vast majority of cases. 0.5 ng/L is our long-term benchmark, not an emergency limit. What changes is that water now uses a noticeable share of EFSA's health budget, especially for a bottle-fed baby. A certified filter fixes the problem at home for a few tens of euros.
At what level does the ARS act?: The legal limit is 100 ng/L for the sum of 20 PFAS. Above it, the ARS asks the supplier for an action plan and can restrict consumption for sensitive groups. Since 2025 it also keeps watch on networks above 20 ng/L for the sum of the four most worrying PFAS, the value recommended by the HCSP.
Does boiling water remove PFAS?: No. PFAS do not evaporate at 100 °C. Boiling reduces the volume of water and slightly concentrates the PFAS. Only certain filters remove them.
Should I get a blood test?: In France it is not offered routinely. In the US, the National Academies recommend testing people with a history of elevated exposure and give two serum thresholds, 2 and 20 ng/mL. If you have drunk water above 20 ng/L of PFAS-4 for years, raise it with your doctor.
How long do PFAS stay in the body?: A long time. After exposure stops, blood concentration halves in 2.7 years for PFOA, 3.4 years for PFOS and 5.3 years for PFHxS. So reducing exposure early matters.

Sources

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.

This site is a data project, not an official source. If in doubt, check with your water supplier or local authority.