Drinking water quality in Osny

Region: Île-de-France Population: 17,954 Water supplier: CYO' Latest sample: 20 March 2026
Passes the EU legal limit but 2.3× over the health limit More PFAS than in 91% of the cities we track

PFAS in drinking water

EU legal limit
0.017 µg/L Limit: 0.1 µg/L within limit

The total of 20 PFAS ("forever chemicals") was last measured at 0.017 µg/L. The EU limit is 0.1 µg/L, so this water is at 17 % of the limit. (19 March 2026)

Health limit (used in Sweden)
0.009 µg/L the 4 most harmful PFAS (PFAS-4) · Limit: 0.004 µg/L 2.3×

The four most harmful PFAS add up to 0.009 µg/L. That is 2.3 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)
Acide sulfonique de perfluorooctane (PFOS) 0.004 µg/L
Acide perfluorobutanoïque (PFBA) 0.003 µg/L
Perfluorohexane sulfonate (PFHXS) 0.003 µg/L
Acide perfluoropentanoïque (PFPEA) 0.002 µg/L
Acide perfluorohexanoïque (PFHXA) 0.002 µg/L
Acide perfluoro-octanoïque (PFOA) 0.002 µg/L
Acide perfluoroheptanoïque (PFHPA) 0.001 µg/L
Acide perfluorononane sulfonique (PFNS) <0,002 µg/L
Acide perfluoro tridecane sulfonique (PFTrDS) <0,005 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 perfluorododécanoique (PFDoDA) <0,001 µg/L
Acide perfluoro-nonanoïque (PFNA) <0,001 µg/L
Acide sulfonique de perfluorobutane (PFBS) <0,001 µg/L
Acide perfluoroheptane sulfonique (PFHpS) <0,002 µg/L
Acide perfluorododécane sulfonique (PFDoDS) <0,001 µg/L
Acide perfluoro tridecanoique (PFTrDA) <0,001 µg/L
Acide perfluoropentane sulfonique (PFPS) <0,001 µg/L
Acide perfluorodecane sulfonique (PFDS) <0,001 µg/L

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Water report for Osny

Official assessment

The authorities have not published an overall verdict for this water.

„Teneur en perchlorates respectant le seuil de 4µg/L préconisé par la D irection Générale de la Santé pour la protection des nourrissons de mo ins de 6 mois.“

Microbiology: not assessed Chemistry: within limit

Values to watch

These values are at least halfway to their legal limit, or over it.

Parameter Value Limit Status
Nitrate 25.4 mg/L ≤ 50 mg/L within limit
Lead 5 µg/L ≤ 10 µg/L within limit
Show all 21 official measurements
Parameter Value Limit Status
Nitrate 25.4 mg/L ≤ 50 mg/L within limit
Nitrite <0,01 mg/L ≤ 0.1 mg/L within limit
Lead 5 µg/L ≤ 10 µg/L within limit
Copper 0.227 mg(Cu)/L ≤ 2 mg(Cu)/L within limit
Nickel <5 µg/L ≤ 20 µg/L within limit
Arsenic <2 µg/L ≤ 10 µg/L within limit
Cadmium <1 µg/L ≤ 5 µg/L within limit
Chromium <5,00 µg/L ≤ 50 µg/L within limit
Uranium <10 µg/L ≤ 30 µg/L within limit
Fluoride 0.11 mg/L ≤ 1.5 mg/L within limit
Escherichia coli 0 n/(100mL) ≤ 0 mL) within limit
Enterococci 0 n/(100mL) ≤ 0 mL) within limit
Coliform bacteria 0 n/(100mL) ≤ 0 mL) within limit
pH 7.5 unité pH 6.5–9 unité pH within limit
Water hardness 28.13 °f no limit informational
Electrical conductivity 629 µS/cm 200–1,100 µS/cm within limit
Chloride 27.2 mg/L ≤ 250 mg/L within limit
Sulphate 49.6 mg/L ≤ 250 mg/L within limit
Sodium 14.4 mg/L ≤ 200 mg/L within limit
Iron <10 µg/L ≤ 200 µg/L within limit
Turbidity 0.16 NFU ≤ 2 NFU within limit

See the full results

See every official test result for Osny, including each PFAS substance. Free, just leave your email.

Frequently asked questions

Is tap water in Osny safe to drink?

All the values shown here (20 March 2026) are within the legal limits, but the authorities have not published an overall verdict for this water.

How high are PFAS levels in Osny's drinking water?

The total of 20 PFAS ("forever chemicals") was last measured at 0.017 µg/L. The EU limit is 0.1 µg/L, so this water is at 17 % of the limit. (below the EU limit)

Does the water in Osny also meet the strictest limits in Europe?

No. The four most harmful PFAS add up to 0.009 µg/L. That is 2.3 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 Osny?

The water hardness in Osny is 28.13 °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 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=95476
License
Licence Ouverte / Open Licence (Etalab)
Retrieved
28 August 2026
Supply networks
OSNY PIGEONNIER, CACP NORD, COM. D'AGGLOMERATION CENTRE, COM. D'AGGLOMERATION BOUCLE NORD

This site is a data project, not an official source. If in doubt, check with your water supplier or local authority.