PFAS in Saint-Cyr-l'École's tap water: 17 ng/L, 34x our 0.5 ng/L benchmark
Last PFAS check: · Source: Hub'eau
PFAS in drinking water
34× 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.
Sample taken in Flins-sur-Seine, on the same distribution network as Saint-Cyr-l'École (SAINT CYR L'ECOLE). The health authority samples one tap per network; a network carries the same treated water everywhere.
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 98% of the cities we track
checked on 8 June 2026
20 PFAS (see each substance)
| PFAS substance | Value |
|---|---|
| Acide perfluoropentanoïque (PFPEA) | 0.009 µg/L |
| Perfluorohexane sulfonate (PFHXS) | 0.008 µg/L |
| Acide perfluorohexanoïque (PFHXA) | 0.007 µg/L |
| Acide perfluorobutanoïque (PFBA) | 0.007 µg/L |
| Acide sulfonique de perfluorooctane (PFOS) | 0.006 µg/L |
| Acide sulfonique de perfluorobutane (PFBS) | 0.003 µg/L |
| Acide perfluoroheptanoïque (PFHPA) | 0.003 µg/L |
| Acide perfluoro-octanoïque (PFOA) | 0.003 µg/L |
| Acide perfluoropentane sulfonique (PFPS) | 0.001 µg/L |
| Acide perfluorodecane sulfonique (PFDS) | <0,001 µg/L |
| Acide perfluoro-decanoïque (PFDA) | <0,001 µg/L |
| Acide perfluoro undecanoïque (PFUnA) | <0,001 µg/L |
| Acide perfluoro tridecanoique (PFTrDA) | <0,001 µg/L |
| Acide perfluorononane sulfonique (PFNS) | <0,002 µg/L |
| Acide perfluoro undecane sulfonique (PFUnDS) | <0,002 µg/L |
| Acide perfluorododécane sulfonique (PFDoDS) | <0,001 µg/L |
| Acide perfluorododécanoique (PFDoDA) | <0,001 µg/L |
| Acide perfluoro-nonanoïque (PFNA) | <0,001 µg/L |
| Acide perfluoro tridecane sulfonique (PFTrDS) | <0,005 µg/L |
| Acide perfluoroheptane sulfonique (PFHpS) | <0,002 µg/L |
Above our health benchmark. Here are some filter options.
- EU legal limit
- 47 ng/L sum of 20 PFAS, below the 100 ng/L limit
- Last PFAS test
- 8 June 2026
- Water supplier
- S.E.O.P.
In Saint-Cyr-l'École, the 4 most closely watched PFAS (PFAS-4) add up to 17 ng/L (0.017 µg/L) at the latest PFAS check on 8 June 2026. That's 34 times our 0.5 ng/L health benchmark, and above Sweden's legal limit of 4 ng/L. Sum of 20 PFAS: 47 ng/L (0.047 µg/L), below the EU legal limit (100 ng/L). Sampled in Flins-sur-Seine, on the same network. 8 checks since 14 January 2026: PFAS-4 from 12 ng/L to 24 ng/L, averaging 17.38 ng/L over 12 months. Rising on the main network. Source: Hub'eau, Qualité de l'eau potable (Ministère de la Santé / OFB / BRGM).
Details and sources
PFAS over time in Saint-Cyr-l'École
27 PFAS checks since 7 April 2025, from the published measurements. Samples from 2 communes on the same network: it's the same water, so each one applies to Saint-Cyr-l'École.
“Calculated”: PFAS-4 worked out from the four substances in the same sample. The chart, averages and trends use lab-published sums only.
| Date | PFAS-4 | Sum of 20 PFAS | Sampled at |
|---|---|---|---|
| 17 ng/L | 47 ng/L | Flins-sur-Seine | |
| 12 ng/L | 28 ng/L | Louveciennes | |
| 20 ng/L | 55 ng/L | Flins-sur-Seine | |
| 20 ng/L | 56 ng/L | Flins-sur-Seine | |
| 13 ng/L | 30 ng/L | Louveciennes | |
| 24 ng/L | 66 ng/L | Flins-sur-Seine | |
| 21 ng/L | 54 ng/L | Flins-sur-Seine | |
| 12 ng/L | 30 ng/L | Louveciennes | |
| 14 ng/L – < 15 ng/L · calculated | 38 ng/L | Flins-sur-Seine | |
| 12 ng/L – < 13 ng/L · calculated | 30 ng/L | Louveciennes | |
| 9 ng/L – < 10 ng/L · calculated | 22 ng/L | Louveciennes | |
| 10 ng/L – < 11 ng/L · calculated | 34 ng/L | Flins-sur-Seine |
Show the 15 earlier checks (back to 7 April 2025)
| 9 ng/L – < 10 ng/L · calculated | 25 ng/L | Louveciennes | |
| 10 ng/L – < 11 ng/L · calculated | 33 ng/L | Flins-sur-Seine | |
| 8 ng/L – < 9 ng/L · calculated | 24 ng/L | Louveciennes | |
| 15 ng/L – < 16 ng/L · calculated | 43 ng/L | Flins-sur-Seine | |
| 19 ng/L – < 20 ng/L · calculated | 52 ng/L | Flins-sur-Seine | |
| 10 ng/L – < 11 ng/L · calculated | 27 ng/L | Louveciennes | |
| 23 ng/L – < 24 ng/L · calculated | 57 ng/L | Flins-sur-Seine | |
| 8 ng/L – < 9 ng/L · calculated | 24 ng/L | Louveciennes | |
| 8 ng/L – < 9 ng/L · calculated | 24 ng/L | Louveciennes | |
| 24 ng/L – < 25 ng/L · calculated | 60 ng/L | Flins-sur-Seine | |
| 16 ng/L – < 17 ng/L · calculated | 47 ng/L | Flins-sur-Seine | |
| 10 ng/L – < 11 ng/L · calculated | 24 ng/L | Louveciennes | |
| 12 ng/L – < 13 ng/L · calculated | 34 ng/L | Louveciennes | |
| 12 ng/L – < 13 ng/L · calculated | 33 ng/L | Louveciennes | |
| 15 ng/L – < 16 ng/L · calculated | 47 ng/L | Flins-sur-Seine |
Calculated values: “<” is an upper bound from published thresholds, “≥” a lower bound, “–” means no published sum or complete measurement. How to read a PFAS result
What the latest check found
At the latest check, the water was within every limit tested.
See all 17 test results
| What was tested | Value | Limit | Status |
|---|---|---|---|
| Nitrate | 24.1 mg/L | ≤ 50 mg/L | within the limit |
| Nitrite | <0,01 mg/L | ≤ 0.5 mg/L | within the limit |
| Lead | <2 µg/L | ≤ 10 µg/L | within the limit |
| Copper | 0.026 mg(Cu)/L | ≤ 2 mg(Cu)/L | within the limit |
| Nickel | <5 µg/L | ≤ 20 µg/L | within the limit |
| Cadmium | <1 µg/L | ≤ 5 µg/L | within the limit |
| Chromium | <5 µg/L | ≤ 50 µg/L | within the limit |
| Escherichia coli | <1 n/(100mL) | ≤ 0 mL) | within the limit |
| Enterococci | <1 n/(100mL) | ≤ 0 mL) | within the limit |
| Coliform bacteria | <1 n/(100mL) | ≤ 0 mL) | within the limit |
| pH | 7.89 unité pH | 6.5–9 unité pH | within the limit |
| Water hardness | 19.7 °f | no limit | for reference |
| Electrical conductivity | 700 µS/cm | 200–1,100 µS/cm | within the limit |
| Chloride | 39 mg/L | ≤ 250 mg/L | within the limit |
| Sulphate | 74 mg/L | ≤ 250 mg/L | within the limit |
| Iron | 11 µg/L | ≤ 200 µg/L | within the limit |
| Turbidity | 0.12 NFU | ≤ 2 NFU | within the limit |
Frequently asked questions
Is tap water in Saint-Cyr-l'École safe to drink?
Yes. At the check on 30 June 2026, the tap water in Saint-Cyr-l'École was within every limit tested. “Eau d'alimentation conforme aux exigences de qualité en vigueur pour l'ensemble des paramètres mesurés.”
How high are PFAS levels in Saint-Cyr-l'École's drinking water?
The total of 20 PFAS ("forever chemicals") was last measured at 47 ng/L. The EU limit is 100 ng/L, so this water is at 47 % of the limit. (below the EU limit)
Does the water in Saint-Cyr-l'École also meet the strictest limits in Europe?
No. The four most harmful PFAS add up to 17 ng/L. That is 4.3 times Sweden's legal limit of 4 ng/L, in force since 2026. Germany will set a similar one in 2028. The water still passes the current EU legal limit (100 ng/L for the total of 20 PFAS).
Are PFAS levels rising in Saint-Cyr-l'École's tap water?
Yes. On the main network, the PFAS-4 sum rose from 12 ng/L (14 January 2026) to 17 ng/L (8 June 2026) across 8 quantified checks. pfasnearme's benchmark is 0.5 ng/L as an annual mean. These history statistics use laboratory-published sums only.
How hard is the water in Saint-Cyr-l'École?
The water hardness in Saint-Cyr-l'École is 19.7 °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 Saint-Cyr-l'École 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=78545
- License
- Licence Ouverte / Open Licence (Etalab)
- Retrieved
- 21 September 2026
- Supply networks
- SAINT CYR L'ECOLE
Water report for Saint-Cyr-l'École
Get new PFAS results for Saint-Cyr-l'École, 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.