PFAS in Mareil-sur-Mauldre's tap water: 22 ng/L, 44x our 0.5 ng/L benchmark
Last PFAS check: · Source: Hub'eau
PFAS in drinking water
44× 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 Villiers-Saint-Frédéric, on the same distribution network as Mareil-sur-Mauldre (LES ESSARTS- LES 4 PILIERS). 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 99% of the cities we track
checked on 25 June 2026
20 PFAS (see each substance)
| PFAS substance | Value |
|---|---|
| Perfluorohexane sulfonate (PFHXS) | 0.01 µg/L |
| Acide sulfonique de perfluorooctane (PFOS) | 0.009 µg/L |
| Acide perfluoropentanoïque (PFPEA) | 0.007 µg/L |
| Acide perfluorohexanoïque (PFHXA) | 0.006 µg/L |
| Acide sulfonique de perfluorobutane (PFBS) | 0.004 µg/L |
| Acide perfluoro-octanoïque (PFOA) | 0.003 µg/L |
| Acide perfluoroheptanoïque (PFHPA) | 0.003 µg/L |
| Acide perfluoropentane sulfonique (PFPS) | 0.002 µg/L |
| Acide perfluorobutanoïque (PFBA) | 0.002 µg/L |
| Acide perfluorodecane sulfonique (PFDS) | <0,001 µg/L |
| Acide perfluoro-decanoïque (PFDA) | <0,001 µg/L |
| Acide perfluorododécanoique (PFDoDA) | <0,001 µg/L |
| Acide perfluoroheptane sulfonique (PFHpS) | <0,002 µg/L |
| Acide perfluoro tridecanoique (PFTrDA) | <0,001 µg/L |
| Acide perfluorononane sulfonique (PFNS) | <0,002 µg/L |
| Acide perfluorododécane sulfonique (PFDoDS) | <0,001 µg/L |
| Acide perfluoro tridecane sulfonique (PFTrDS) | <0,005 µg/L |
| Acide perfluoro undecanoïque (PFUnA) | <0,001 µg/L |
| Acide perfluoro undecane sulfonique (PFUnDS) | <0,002 µg/L |
| Acide perfluoro-nonanoïque (PFNA) | <0,001 µg/L |
Above our health benchmark. Here are some filter options.
- EU legal limit
- 46 ng/L sum of 20 PFAS, below the 100 ng/L limit
- Last PFAS test
- 25 June 2026
- Water supplier
- SAUR
In Mareil-sur-Mauldre, the 4 most closely watched PFAS (PFAS-4) add up to 22 ng/L (0.022 µg/L) at the latest PFAS check on 25 June 2026. That's 44 times our 0.5 ng/L health benchmark, and above Sweden's legal limit of 4 ng/L. Sum of 20 PFAS: 46 ng/L (0.046 µg/L), below the EU legal limit (100 ng/L). Sampled in Villiers-Saint-Frédéric, on the same network. 7 checks since 18 February 2026: PFAS-4 from 10 ng/L to 24 ng/L, averaging 20.67 ng/L over 12 months. No clear trend. Source: Hub'eau, Qualité de l'eau potable (Ministère de la Santé / OFB / BRGM).
Details and sources
PFAS over time in Mareil-sur-Mauldre
31 PFAS checks since 20 June 2024, from the published measurements. Samples from 6 communes on the same network: it's the same water, so each one applies to Mareil-sur-Mauldre. Samples come from 2 distribution networks. The trend refers to the network “LES ESSARTS- LES 4 PILIERS”.
“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 | Network |
|---|---|---|---|---|
| 22 ng/L | 46 ng/L | Villiers-Saint-Frédéric | LES ESSARTS- LES 4 PILIERS | |
| 17 ng/L | 47 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 10 ng/L | 25 ng/L | Beynes | BEYNES ST SANTIN | |
| 20 ng/L | 55 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 20 ng/L | 56 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 24 ng/L | 66 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 21 ng/L | 54 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 14 ng/L – < 15 ng/L · calculated | 38 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| < 4 ng/L · calculated | < 29 ng/L | Rosay | BEYNES ST SANTIN | |
| 8 ng/L – < 9 ng/L · calculated | 21 ng/L | Mareil-sur-Mauldre | BEYNES ST SANTIN, LES ESSARTS- LES 4 PILIERS | |
| 6 ng/L – < 7 ng/L · calculated | 6 ng/L | Villiers-Saint-Frédéric | LES ESSARTS- LES 4 PILIERS | |
| 10 ng/L – < 11 ng/L · calculated | 34 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS |
Show the 19 earlier checks (back to 20 June 2024)
| 10 ng/L – < 11 ng/L · calculated | 33 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 15 ng/L – < 16 ng/L · calculated | 43 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| < 4 ng/L · calculated | < 29 ng/L | Saint-Lubin-de-la-Haye | BEYNES ST SANTIN | |
| 5 ng/L – < 6 ng/L · calculated | 14 ng/L | Mareil-sur-Mauldre | BEYNES ST SANTIN, LES ESSARTS- LES 4 PILIERS | |
| 19 ng/L – < 20 ng/L · calculated | 52 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 23 ng/L – < 24 ng/L · calculated | 57 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 8 ng/L – < 9 ng/L · calculated | 8 ng/L | Villiers-Saint-Frédéric | LES ESSARTS- LES 4 PILIERS | |
| 24 ng/L – < 25 ng/L · calculated | 60 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| < 4 ng/L · calculated | < 28 ng/L | Rosay | BEYNES ST SANTIN | |
| 16 ng/L – < 17 ng/L · calculated | 47 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| 2 ng/L – < 4 ng/L · calculated | 36 ng/L | Saint-Lubin-de-la-Haye | BEYNES ST SANTIN | |
| 17 ng/L – < 18 ng/L · calculated | 34 ng/L | Mareil-sur-Mauldre | BEYNES ST SANTIN, LES ESSARTS- LES 4 PILIERS | |
| < 4 ng/L · calculated | 3 ng/L | Saint-Lubin-de-la-Haye | BEYNES ST SANTIN | |
| < 4 ng/L · calculated | 5 ng/L | Rosay | BEYNES ST SANTIN | |
| 16 ng/L – < 17 ng/L · calculated | 31 ng/L | Mareil-sur-Mauldre | BEYNES ST SANTIN, LES ESSARTS- LES 4 PILIERS | |
| 7 ng/L – < 8 ng/L · calculated | 12 ng/L | Villiers-Saint-Frédéric | LES ESSARTS- LES 4 PILIERS | |
| 15 ng/L – < 16 ng/L · calculated | 47 ng/L | Flins-sur-Seine | LES ESSARTS- LES 4 PILIERS | |
| < 4 ng/L · calculated | < 1 ng/L | Saint-Lubin-de-la-Haye | BEYNES ST SANTIN | |
| 1 ng/L – < 4 ng/L · calculated | 1 ng/L | Saint-Lubin-de-la-Haye | BEYNES ST SANTIN |
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.
Values to watch
These results are close to their legal limit, or over it.
| What was tested | Value | Limit | Status |
|---|---|---|---|
| Nitrate | 43.1 mg/L | ≤ 50 mg/L | within the limit |
See all 20 test results
| What was tested | Value | Limit | Status |
|---|---|---|---|
| Nitrate | 43.1 mg/L | ≤ 50 mg/L | within the limit |
| Nitrite | <0,01 mg/L | ≤ 0.1 mg/L | within the limit |
| Lead | <2 µg/L | ≤ 10 µg/L | within the limit |
| Copper | 0.146 mg(Cu)/L | ≤ 2 mg(Cu)/L | within the limit |
| Nickel | <5 µg/L | ≤ 20 µg/L | within the limit |
| Arsenic | <2 µg/L | ≤ 10 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 |
| Fluoride | 0.29 mg/L | ≤ 1.5 mg/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 | 7.7 unité pH | 6.5–9 unité pH | within the limit |
| Water hardness | 21.54 °f | no limit | for reference |
| Electrical conductivity | 764 µS/cm | 200–1,100 µS/cm | within the limit |
| Chloride | 42.4 mg/L | ≤ 250 mg/L | within the limit |
| Sulphate | 91 mg/L | ≤ 250 mg/L | within the limit |
| Sodium | 63.2 mg/L | ≤ 200 mg/L | within the limit |
| Iron | <10 µg/L | ≤ 200 µg/L | within the limit |
| Turbidity | <0,1 NFU | ≤ 2 NFU | within the limit |
Frequently asked questions
Is tap water in Mareil-sur-Mauldre safe to drink?
Yes. At the check on 25 June 2026, the tap water in Mareil-sur-Mauldre 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 Mareil-sur-Mauldre's drinking water?
The total of 20 PFAS ("forever chemicals") was last measured at 46 ng/L. The EU limit is 100 ng/L, so this water is at 46 % of the limit. (below the EU limit)
Does the water in Mareil-sur-Mauldre also meet the strictest limits in Europe?
No. The four most harmful PFAS add up to 22 ng/L. That is 5.5 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 Mareil-sur-Mauldre's tap water?
No clear trend. Since 20 June 2024, 7 checks have been published; on the main network the PFAS-4 sum ranged between 17 ng/L and 24 ng/L (6 quantified values), at times below the detection limit. pfasnearme only reports a trend from a change of at least 25 % and 1 ng/L. These history statistics use laboratory-published sums only.
How hard is the water in Mareil-sur-Mauldre?
The water hardness in Mareil-sur-Mauldre is 21.5 °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.
Same water network
Same distribution network as Mareil-sur-Mauldre, so in principle the same water.
Nearby communes
The closest to Mareil-sur-Mauldre 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=78368
- License
- Licence Ouverte / Open Licence (Etalab)
- Retrieved
- 21 September 2026
- Supply networks
- BEYNES ST SANTIN, LES ESSARTS- LES 4 PILIERS
Water report for Mareil-sur-Mauldre
Get new PFAS results for Mareil-sur-Mauldre, 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.