PFAS in Ouessant's tap water: 2.1 ng/L, 4.2x our 0.5 ng/L benchmark
Last PFAS check: · Source: Hub'eau
PFAS in drinking water
4.2× above our health benchmark
0.5 ng/L is our benchmark, not an official limit. Same EFSA method as Sweden, Denmark and the Netherlands, but stricter. It's a yearly average, compared here with the latest check.
More about this result
The US also limits PFOA and PFOS to 4 ng/L each, per substance.
Substances below the detection limit count as 0, so the real total may be higher.
One of these four, PFOA, is classified as causing cancer in humans by the WHO's cancer research agency (IARC).
More PFAS than in 88% of the cities we track
checked on 9 July 2025
20 PFAS (see each substance)
| PFAS substance | Value |
|---|---|
| Acide perfluorobutanoïque (PFBA) | 0.013 µg/L |
| Acide perfluoropentanoïque (PFPEA) | 0.0045 µg/L |
| Acide sulfonique de perfluorooctane (PFOS) | 0.0021 µg/L |
| Acide perfluorodecane sulfonique (PFDS) | <0,001 µg/L |
| Acide perfluoropentane sulfonique (PFPS) | <0,001 µg/L |
| Acide perfluorononane sulfonique (PFNS) | <0,001 µg/L |
| Acide perfluoro undecane sulfonique (PFUnDS) | <0,001 µg/L |
| Acide perfluoro-octanoïque (PFOA) | <0,002 µg/L |
| Acide perfluoroheptanoïque (PFHPA) | <0,005 µg/L |
| Acide perfluoro-decanoïque (PFDA) | <0,002 µg/L |
| Acide perfluoro tridecanoique (PFTrDA) | <0,002 µg/L |
| Acide perfluoro undecanoïque (PFUnA) | <0,002 µg/L |
| Acide perfluorododécanoique (PFDoDA) | <0,002 µg/L |
| Perfluorohexane sulfonate (PFHXS) | <0,002 µg/L |
| Acide perfluoro tridecane sulfonique (PFTrDS) | <0,001 µg/L |
| Acide sulfonique de perfluorobutane (PFBS) | <0,005 µg/L |
| Acide perfluoro-nonanoïque (PFNA) | <0,001 µg/L |
| Acide perfluorohexanoïque (PFHXA) | <0,005 µg/L |
| Acide perfluorododécane sulfonique (PFDoDS) | <0,001 µg/L |
| Acide perfluoroheptane sulfonique (PFHpS) | <0,002 µg/L |
Above our health benchmark. Here are some filter options.
- EU legal limit
- 19.6 ng/L sum of 20 PFAS, below the 100 ng/L limit
- Last PFAS test
- 9 July 2025
- Water supplier
- SPL EAU DU PONANT
In Ouessant, the 4 most closely watched PFAS (PFAS-4) add up to 2.1 ng/L (0.0021 µg/L) at the latest PFAS check on 9 July 2025. That's 4.2 times our 0.5 ng/L health benchmark, but below Sweden's legal limit of 4 ng/L. Sum of 20 PFAS: 19.6 ng/L (0.0196 µg/L), below the EU legal limit (100 ng/L). Source: Hub'eau, Qualité de l'eau potable (Ministère de la Santé / OFB / BRGM).
Details and sources
PFAS over time in Ouessant
A single PFAS check has been published for Ouessant so far (9 July 2025). A history will build up with the next checks; this page is refreshed weekly.
What the latest check found
The authorities have not published an overall verdict for this water.
See all 18 test results
| What was tested | Value | Limit | Status |
|---|---|---|---|
| Nitrate | <0,5 mg/L | ≤ 50 mg/L | within the limit |
| Nitrite | <0,01 mg/L | ≤ 0.5 mg/L | within the limit |
| Arsenic | <1 µg/L | ≤ 10 µg/L | within the limit |
| Cadmium | <0,1 µg/L | ≤ 5 µg/L | within the limit |
| Chromium | <1 µg/L | ≤ 50 µg/L | within the limit |
| Uranium | <0,1 µg/L | ≤ 30 µg/L | within the limit |
| Fluoride | 0.1 mg/L | ≤ 1.5 mg/L | within the limit |
| Escherichia coli | 0 n/(100mL) | ≤ 0 mL) | within the limit |
| Enterococci | 0 n/(100mL) | ≤ 0 mL) | within the limit |
| Coliform bacteria | ILLISIBL n/(100mL) | ≤ 0 mL) | no verdict |
| pH | 7.5 unité pH | 6.5–9 unité pH | within the limit |
| Water hardness | 21 °f | no limit | for reference |
| Electrical conductivity | 914 µS/cm | 200–1,100 µS/cm | within the limit |
| Chloride | 213.1 mg/L | ≤ 250 mg/L | within the limit |
| Sulphate | 16 mg/L | ≤ 250 mg/L | within the limit |
| Sodium | 66.7 mg/L | ≤ 200 mg/L | within the limit |
| Iron | 6.4 µg/L | ≤ 200 µg/L | within the limit |
| Turbidity | 0.17 NFU | ≤ 2 NFU | within the limit |
Frequently asked questions
Is tap water in Ouessant safe to drink?
All the values shown here (29 July 2026) are within the legal limits, but the authorities have not published an overall verdict for this water. “Eau d'alimentation conforme aux exigences de qualité en vigueur, absence de détection de toxines de cyanobactéries.”
How high are PFAS levels in Ouessant's drinking water?
The total of 20 PFAS ("forever chemicals") was last measured at 19.6 ng/L. The EU limit is 100 ng/L, so this water is at 20 % of the limit. (below the EU limit)
Does the water in Ouessant also meet the strictest limits in Europe?
Yes. Even against Europe's strictest legal limit, Sweden's 4 ng/L in force since 2026, the measured value of 2.1 ng/L stays below.
How hard is the water in Ouessant?
The water hardness in Ouessant is 21 °f (medium). This mainly matters for household appliances and detergent dosing, not for health.
Where does this data come from?
All values come from official publications: Hub'eau, Qualité de l'eau potable (Ministère de la Santé / OFB / BRGM). Retrieved on 21 September 2026.
Nearby communes
The closest to Ouessant on this site.
Data source
- Hub'eau, Qualité de l'eau potable (Ministère de la Santé / OFB / BRGM)
- https://hubeau.eaufrance.fr/api/v1/qualite_eau_potable/resultats_dis?code_commune=29155
- License
- Licence Ouverte / Open Licence (Etalab)
- Retrieved
- 21 September 2026
- Supply networks
- OUESSANT (LAN-VIHAN)
Water report for Ouessant
Get new PFAS results for Ouessant, with a short explanation. At most one update a week, only when there's something new.
This site is a data project, not an official source. If in doubt, check with your water supplier or local authority.