PFAS in Tressin's tap water: 7 ng/L, 14x our 0.5 ng/L benchmark
Last PFAS check: · Source: Hub'eau
PFAS in drinking water
14× 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 Lys-lez-Lannoy, on the same distribution network as Tressin (HEM). 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 94% of the cities we track
checked on 26 June 2026
20 PFAS (see each substance)
| PFAS substance | Value |
|---|---|
| Acide perfluorohexanoïque (PFHXA) | 0.003 µg/L |
| Acide perfluorobutanoïque (PFBA) | 0.003 µg/L |
| Perfluorohexane sulfonate (PFHXS) | 0.003 µg/L |
| Acide sulfonique de perfluorooctane (PFOS) | 0.002 µg/L |
| Acide perfluoropentanoïque (PFPEA) | 0.002 µg/L |
| Acide perfluoro-octanoïque (PFOA) | 0.002 µg/L |
| Acide sulfonique de perfluorobutane (PFBS) | 0.002 µg/L |
| Acide perfluorononane sulfonique (PFNS) | <0,002 µg/L |
| Acide perfluoro-nonanoïque (PFNA) | <0,001 µg/L |
| Acide perfluorodecane sulfonique (PFDS) | <0,001 µg/L |
| Acide perfluoro undecane sulfonique (PFUnDS) | <0,002 µg/L |
| Acide perfluoro undecanoïque (PFUnA) | <0,001 µg/L |
| Acide perfluoro-decanoïque (PFDA) | <0,001 µg/L |
| Acide perfluoro tridecane sulfonique (PFTrDS) | <0,005 µg/L |
| Acide perfluoropentane sulfonique (PFPS) | <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 perfluorododécane sulfonique (PFDoDS) | <0,001 µg/L |
| Acide perfluoroheptanoïque (PFHPA) | <0,001 µg/L |
Above our health benchmark. Here are some filter options.
- EU legal limit
- 17 ng/L sum of 20 PFAS, below the 100 ng/L limit
- Last PFAS test
- 26 June 2026
- Water supplier
- ILEO
In Tressin, the 4 most closely watched PFAS (PFAS-4) add up to 7 ng/L (0.007 µg/L) at the latest PFAS check on 26 June 2026. That's 14 times our 0.5 ng/L health benchmark, and above Sweden's legal limit of 4 ng/L. Sum of 20 PFAS: 17 ng/L (0.017 µg/L), below the EU legal limit (100 ng/L). Sampled in Lys-lez-Lannoy, on the same network. 9 checks since 13 February 2026: PFAS-4 up to 12 ng/L, sometimes below the detection limit, averaging at least 5.11 ng/L over 12 months (non-detects as 0). Falling 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 Tressin
12 PFAS checks since 10 January 2024, from the published measurements. Samples from 6 communes on the same network: it's the same water, so each one applies to Tressin.
“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 |
|---|---|---|---|
| 7 ng/L | 17 ng/L | Lys-lez-Lannoy | |
| < 1 ng/L | 1 ng/L | Prémesques | |
| 12 ng/L | 17 ng/L | Wavrin | |
| 11 ng/L | 29 ng/L | Villeneuve-d'Ascq | |
| < 1 ng/L | < 1 ng/L | Wattrelos | |
| < 1 ng/L | < 1 ng/L | Hem | |
| < 1 ng/L | < 1 ng/L | Wattrelos | |
| 6 ng/L | 17 ng/L | Hem | |
| 10 ng/L | 15 ng/L | Wavrin | |
| < 10 ng/L · calculated | 0 ng/L | Hem | |
| – | 15.6 ng/L | Wavrin | |
| – | 14.6 ng/L | Wavrin |
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 | 1.69 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 | 0.031 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 | 7.5 unité pH | 6.5–9 unité pH | within the limit |
| Water hardness | 44.17 °f | no limit | for reference |
| Electrical conductivity | 1,056 µS/cm | 200–1,100 µS/cm | within the limit |
| Chloride | 55 mg/L | ≤ 250 mg/L | within the limit |
| Sulphate | 205 mg/L | ≤ 250 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 Tressin safe to drink?
Yes. At the check on 26 June 2026, the tap water in Tressin 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 Tressin's drinking water?
The total of 20 PFAS ("forever chemicals") was last measured at 17 ng/L. The EU limit is 100 ng/L, so this water is at 17 % of the limit. (below the EU limit)
Does the water in Tressin also meet the strictest limits in Europe?
No. The four most harmful PFAS add up to 7 ng/L. That is 1.75 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 Tressin's tap water?
No, they are falling. On the main network, the PFAS-4 sum went from 10 ng/L (13 February 2026) to 7 ng/L (26 June 2026) across 5 quantified checks. These history statistics use laboratory-published sums only.
How hard is the water in Tressin?
The water hardness in Tressin is 44.2 °f (hard). 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 Tressin, so in principle the same water.
Nearby communes
The closest to Tressin 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=59602
- License
- Licence Ouverte / Open Licence (Etalab)
- Retrieved
- 21 September 2026
- Supply networks
- HEM
Water report for Tressin
Get new PFAS results for Tressin, 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.