PFAS in Besançon's tap water: 5 ng/L, 10x our 0.5 ng/L benchmark
Last PFAS check: · Source: Hub'eau
PFAS in drinking water
10× 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 92% of the cities we track
checked on 29 July 2026
20 PFAS (see each substance)
| PFAS substance | Value |
|---|---|
| Acide perfluoropentanoïque (PFPEA) | 0.041 µg/L |
| Acide perfluorohexanoïque (PFHXA) | 0.034 µg/L |
| Acide perfluorobutanoïque (PFBA) | 0.013 µg/L |
| Acide perfluoroheptanoïque (PFHPA) | 0.008 µg/L |
| Acide perfluoro-octanoïque (PFOA) | 0.003 µg/L |
| Acide sulfonique de perfluorobutane (PFBS) | 0.002 µg/L |
| Acide sulfonique de perfluorooctane (PFOS) | 0.002 µg/L |
| Acide perfluoro undecanoïque (PFUnA) | <0,001 µg/L |
| Acide perfluoropentane sulfonique (PFPS) | <0,001 µg/L |
| Acide perfluoro undecane sulfonique (PFUnDS) | <0,002 µg/L |
| Acide perfluorodecane sulfonique (PFDS) | <0,001 µg/L |
| Acide perfluoro tridecanoique (PFTrDA) | <0,001 µg/L |
| Acide perfluoroheptane sulfonique (PFHpS) | <0,002 µg/L |
| Acide perfluorododécanoique (PFDoDA) | <0,001 µg/L |
| Acide perfluoro-nonanoïque (PFNA) | <0,001 µg/L |
| Acide perfluoro-decanoïque (PFDA) | <0,001 µg/L |
| Perfluorohexane sulfonate (PFHXS) | <0,001 µg/L |
| Acide perfluorononane sulfonique (PFNS) | <0,002 µg/L |
| Acide perfluoro tridecane sulfonique (PFTrDS) | <0,005 µg/L |
| Acide perfluorododécane sulfonique (PFDoDS) | <0,001 µg/L |
Fails a current legal limit. Here are some filter options.
- EU legal limit
- 103 ng/L sum of 20 PFAS, above the 100 ng/L limit
- Last PFAS test
- 29 July 2026
- Water supplier
- CU GRAND BESANÇON MÉTROPOLE
In Besançon, the 4 most closely watched PFAS (PFAS-4) add up to 5 ng/L (0.005 µg/L) at the latest PFAS check on 29 July 2026. That's 10 times our 0.5 ng/L health benchmark, and above Sweden's legal limit of 4 ng/L. Sum of 20 PFAS: 103 ng/L (0.103 µg/L), above the EU legal limit (100 ng/L). 18 checks since 2 July 2025: PFAS-4 up to 7 ng/L, sometimes below the detection limit, averaging at least 2.7 ng/L over 12 months (non-detects as 0). 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 Besançon
30 PFAS checks since 23 January 2024, from the published measurements. Samples from 3 communes on the same network: it's the same water, so each one applies to Besançon. Samples come from 5 distribution networks. The trend refers to the network “GBM BESANCON ARCIER”.
“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 |
|---|---|---|---|---|
| 5 ng/L | 103 ng/L | Besançon | GBM BESANCON ARCIER | |
| < 4 ng/L | < 29 ng/L | Étalans | GBM BESANCON CHAPELLE DES BUIS | |
| < 4 ng/L | 7 ng/L | Besançon | GBM BESANCON ARCIER | |
| < 4 ng/L | < 29 ng/L | Besançon | GBM BESANCON CHENECEY BUILLON | |
| 4 ng/L | 6 ng/L | Besançon | GBM BESANCON CHAILLUZ NOVILLARS | |
| < 4 ng/L | < 29 ng/L | Besançon | GBM BESANCON MONTRAPON-UNIVERSITE | |
| < 4 ng/L | < 29 ng/L | Besançon | GBM BESANCON CHENECEY BUILLON | |
| 2 ng/L | 36 ng/L | Besançon | GBM BESANCON ARCIER | |
| 1 ng/L | 22 ng/L | Besançon | GBM BESANCON ARCIER | |
| 1 ng/L | 16 ng/L | Besançon | GBM BESANCON ARCIER | |
| < 4 ng/L | < 29 ng/L | Besançon | GBM BESANCON CHENECEY BUILLON, GBM BESANCON MONTRAPON-UNIVERSITE | |
| 7 ng/L | 13 ng/L | Besançon | GBM BESANCON CHAILLUZ NOVILLARS, GBM BESANCON MONTRAPON-UNIVERSITE |
Show the 18 earlier checks (back to 23 January 2024)
| 2 ng/L | 35 ng/L | Besançon | GBM BESANCON ARCIER | |
| 3 ng/L | 34 ng/L | Besançon | GBM BESANCON ARCIER | |
| 4 ng/L | 41 ng/L | Besançon | GBM BESANCON ARCIER | |
| 5 ng/L | 59 ng/L | Besançon | GBM BESANCON ARCIER | |
| 4 ng/L | 54 ng/L | Besançon | GBM BESANCON ARCIER | |
| 7 ng/L – < 9 ng/L · calculated | 139 ng/L | Besançon | GBM BESANCON ARCIER | |
| 5 ng/L | 5 ng/L | Besançon | GBM BESANCON CHAILLUZ NOVILLARS, GBM BESANCON MONTRAPON-UNIVERSITE | |
| < 4 ng/L · calculated | 1 ng/L | Besançon | GBM BESANCON CHENECEY BUILLON, GBM BESANCON MONTRAPON-UNIVERSITE | |
| 6 ng/L – < 8 ng/L · calculated | 11 ng/L | Besançon | GBM BESANCON CHAILLUZ NOVILLARS, GBM BESANCON MONTRAPON-UNIVERSITE | |
| 3 ng/L – < 5 ng/L · calculated | 57 ng/L | Besançon | GBM BESANCON ARCIER | |
| < 4 ng/L · calculated | < 100 ng/L | Besançon | GBM BESANCON CHENECEY BUILLON, GBM BESANCON MONTRAPON-UNIVERSITE | |
| < 4 ng/L · calculated | 17 ng/L | Besançon | GBM BESANCON ARCIER | |
| < 4 ng/L · calculated | < 100 ng/L | Besançon | GBM BESANCON CHENECEY BUILLON, GBM BESANCON MONTRAPON-UNIVERSITE | |
| 9 ng/L – < 11 ng/L · calculated | 16 ng/L | Besançon | GBM BESANCON CHAILLUZ NOVILLARS, GBM BESANCON MONTRAPON-UNIVERSITE | |
| 1 ng/L – < 4 ng/L · calculated | 16 ng/L | Besançon | GBM BESANCON ARCIER | |
| 7 ng/L – < 9 ng/L · calculated | 79 ng/L | Besançon | GBM BESANCON ARCIER | |
| 4.5 ng/L – < 6.5 ng/L · calculated | 4.5 ng/L | Besançon | GBM BESANCON ARCIER | |
| 2 ng/L – < 4 ng/L · calculated | 17.5 ng/L | Montfaucon | GBM BESANCON ARCIER |
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 over at least one limit.
See all 21 test results
| What was tested | Value | Limit | Status |
|---|---|---|---|
| Nitrate | 13 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 | 0.549 mg(Cu)/L | ≤ 2 mg(Cu)/L | within the limit |
| Nickel | <2 µg/L | ≤ 20 µg/L | within the limit |
| Arsenic | <1 µg/L | ≤ 10 µg/L | within the limit |
| Cadmium | <1 µg/L | ≤ 5 µg/L | within the limit |
| Chromium | <2 µg/L | ≤ 50 µg/L | within the limit |
| Uranium | <10 µg/L | ≤ 30 µg/L | within the limit |
| Fluoride | 0.06 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 | 8 unité pH | 6.5–9 unité pH | within the limit |
| Water hardness | 24.4 °f | no limit | for reference |
| Electrical conductivity | 543 µS/cm | 200–1,100 µS/cm | within the limit |
| Chloride | 12 mg/L | ≤ 250 mg/L | within the limit |
| Sulphate | 7.9 mg/L | ≤ 250 mg/L | within the limit |
| Sodium | 6.34 mg/L | ≤ 200 mg/L | within the limit |
| Iron | <10 µg/L | ≤ 200 µg/L | within the limit |
| Turbidity | <0,2 NFU | ≤ 2 NFU | within the limit |
Frequently asked questions
Is tap water in Besançon safe to drink?
At the latest check, the water was over at least one limit. “Présence de composés perfluorés (PFAS) nécessitant la mise en œuvre d’ un suivi renforcé de la qualité de l’eau afin de confirmer la non-conformité. Des recontrôles sont programmés”
How high are PFAS levels in Besançon's drinking water?
The total of 20 PFAS ("forever chemicals") was last measured at 103 ng/L. The EU limit is 100 ng/L, so this water is at 103 % of the limit. (above the EU limit)
Does the water in Besançon also meet the strictest limits in Europe?
No. The four most harmful PFAS add up to 5 ng/L. That is 1.25 times Sweden's legal limit of 4 ng/L, in force since 2026. Germany will set a similar one in 2028. The sum of 20 PFAS is 103 ng/L, above the EU legal limit of 100 ng/L.
Are PFAS levels rising in Besançon's tap water?
Yes. On the main network, the PFAS-4 sum rose from 4 ng/L (17 September 2025) to 5 ng/L (29 July 2026) across 9 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 Besançon?
The water hardness in Besançon is 24.4 °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 Besançon, so in principle the same water.
Nearby communes
The closest to Besançon 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=25056
- License
- Licence Ouverte / Open Licence (Etalab)
- Retrieved
- 21 September 2026
- Supply networks
- GBM BESANCON ARCIER, GBM BESANCON CHENECEY BUILLON, GBM BESANCON CHAILLUZ NOVILLARS, GBM BESANCON CHAPELLE DES BUIS, GBM BESANCON MONTRAPON-UNIVERSITE
Water report for Besançon
Get new PFAS results for Besançon, 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.