Drinking water quality in Cognin
PFAS in drinking water
The total of 20 PFAS ("forever chemicals") was last measured at 0.028 µg/L. The EU limit is 0.1 µg/L, so this water is at 28 % of the limit. (10 June 2026)
The four most harmful PFAS add up to 0.014 µg/L. That is 3.5 times the health limit of 0.004 µg/L that Sweden made law in 2026. Germany will set a similar limit in 2028.
One of these four, PFOA, is classified as causing cancer in humans by the WHO's cancer research agency (IARC).
Substances too small to measure count as 0, so the real total may be higher.
20 PFAS (see each substance)
| Perfluorohexane sulfonate (PFHXS) | 0.006 µg/L |
| Acide sulfonique de perfluorooctane (PFOS) | 0.005 µg/L |
| Acide perfluorohexanoïque (PFHXA) | 0.004 µg/L |
| Acide perfluoro-octanoïque (PFOA) | 0.003 µg/L |
| Acide perfluorobutanoïque (PFBA) | 0.003 µg/L |
| Acide perfluoropentanoïque (PFPEA) | 0.003 µg/L |
| Acide sulfonique de perfluorobutane (PFBS) | 0.002 µg/L |
| Acide perfluoroheptanoïque (PFHPA) | 0.001 µg/L |
| Acide perfluoropentane sulfonique (PFPS) | 0.001 µg/L |
| Acide perfluoro undecane sulfonique (PFUnDS) | <0,002 µg/L |
| Acide perfluoroheptane sulfonique (PFHpS) | <0,002 µg/L |
| Acide perfluoro undecanoïque (PFUnA) | <0,001 µg/L |
| Acide perfluoro tridecanoique (PFTrDA) | <0,001 µg/L |
| Acide perfluorododécane sulfonique (PFDoDS) | <0,001 µg/L |
| Acide perfluorodecane sulfonique (PFDS) | <0,001 µg/L |
| Acide perfluorododécanoique (PFDoDA) | <0,001 µg/L |
| Acide perfluorononane sulfonique (PFNS) | <0,002 µg/L |
| Acide perfluoro tridecane sulfonique (PFTrDS) | <0,005 µg/L |
| Acide perfluoro-nonanoïque (PFNA) | <0,001 µg/L |
| Acide perfluoro-decanoïque (PFDA) | <0,001 µg/L |
Water report for Cognin
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Official assessment
The latest official test passed all quality requirements.
„Eau d'alimentation conforme aux limites de qualité et non conforme aux références de qualité.“
Values to watch
These values are at least halfway to their legal limit, or over it.
| Parameter | Value | Limit | Status |
|---|---|---|---|
| Coliform bacteria | 1 n/(100mL) | ≤ 0 mL) | exceeded |
Show all 21 official measurements
| Parameter | Value | Limit | Status |
|---|---|---|---|
| Nitrate | 9.8 mg/L | ≤ 50 mg/L | within limit |
| Nitrite | <0,03 mg/L | ≤ 0.5 mg/L | within limit |
| Lead | <0,20 µg/L | ≤ 10 µg/L | within limit |
| Copper | <0,001 mg(Cu)/L | ≤ 2 mg(Cu)/L | within limit |
| Nickel | <1 µg/L | ≤ 20 µg/L | within limit |
| Arsenic | <0,50 µg/L | ≤ 10 µg/L | within limit |
| Cadmium | <0,10 µg/L | ≤ 5 µg/L | within limit |
| Chromium | <0,50 µg/L | ≤ 50 µg/L | within limit |
| Uranium | 0.53 µg/L | ≤ 30 µg/L | within limit |
| Fluoride | 0.1 mg/L | ≤ 1.5 mg/L | within limit |
| Escherichia coli | <1 n/(100mL) | ≤ 0 mL) | within limit |
| Enterococci | <1 n/(100mL) | ≤ 0 mL) | within limit |
| Coliform bacteria | 1 n/(100mL) | ≤ 0 mL) | exceeded |
| pH | 7.09 unité pH | 6.5–9.5 pH | within limit |
| Water hardness | 31.5 °f | no limit | informational |
| Electrical conductivity | 595 µS/cm | 200–1,100 µS/cm | within limit |
| Chloride | 11.5 mg/L | ≤ 250 mg/L | within limit |
| Sulphate | 27.1 mg/L | ≤ 250 mg/L | within limit |
| Sodium | 10.1 mg/L | ≤ 200 mg/L | within limit |
| Iron | <10 µg/L | ≤ 200 µg/L | within limit |
| Turbidity | <0,20 NFU | ≤ 2 NFU | within limit |
Frequently asked questions
Is tap water in Cognin safe to drink?
Yes. The latest official test (10 June 2026) checked the tap water in Cognin and it passed every requirement.
How high are PFAS levels in Cognin's drinking water?
The total of 20 PFAS ("forever chemicals") was last measured at 0.028 µg/L. The EU limit is 0.1 µg/L, so this water is at 28 % of the limit. (below the EU limit)
Does the water in Cognin also meet the strictest limits in Europe?
No. The four most harmful PFAS add up to 0.014 µg/L. That is 3.5 times the health limit of 0.004 µg/L that Sweden made law in 2026. The water still passes the current EU limit (0.1 µg/L for the total of 20 PFAS).
How hard is the water in Cognin?
The water hardness in Cognin is 31.5 °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 28 August 2026.
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=73087
- License
- Licence Ouverte / Open Licence (Etalab)
- Retrieved
- 28 August 2026
- Supply networks
- RESEAU DES ILES, RESEAU DE PASTEUR
This site is a data project, not an official source. If in doubt, check with your water supplier or local authority.