France Drinking Water Quality Dataset

4,855

Observations

1,387

Series

101

Subjects

2022–2025

Period covered

Methodology

Computed by Hydrionis from per-sample results published by the regional health agencies through Hub’Eau. The governing decision is the treatment of censored results: French results below the laboratory detection limit are published with a textual result beginning "<" alongside a numeric field set to zero. Hydrionis treats the textual form as authoritative. Censored results are counted, published as a quantified-share series, excluded from every mean rather than substituted with zero or half the detection limit, and never counted as exceeding a limit. The resulting mean is therefore an upper bound and is labelled as one. Only complete calendar years are aggregated, and a department-year needs thirty results before a rate is published.

What this dataset cannot tell you

Read before relying on these figures

A mean computed over quantified results only is biased upward. Where the quantified share is low — as it is for PFOS almost everywhere — the mean describes the detectable minority of samples rather than the water supplied, and must be read with that share.
Detection limits improve over time and differ between laboratories, so a rise in the quantified share can reflect better analysis rather than more of the substance.
Department-level statistics average over supplies that may differ greatly. A department with one contaminated small supply and a hundred clean ones will not look contaminated.
An exceedance in a department-year does not mean non-compliant water was supplied: regulators act on breaches, and the sample is what triggers that action.
Restricted to five determinands from a monitoring programme covering hundreds. Absence of a determinand here is not evidence about it.

Coverage

Subjects	French departments, metropolitan and overseas — 101 held
Period	2022–2025
Units	%, mg/l as NO₃, samples, µg/l
Update cadence	Annually
Identifier	`france-drinking-water-quality` v1.0.0

Fields

Data dictionary →

Every metric this dataset carries, with the unit it is stored in and the geography level it is reported at. Full definitions are in the data dictionary.

Identifier	Field	Unit	Reported at
`dw-nitrate-concentration`	Nitrate in drinking water Mean concentration of nitrate, expressed as the nitrate ion in treated drinking water, computed over quantified samples only.	mg/l as NO₃	supply-zone, local-authority, county
`dw-nitrate-quantified`	Nitrate quantified sample share Percentage of drinking-water samples analysed for nitrate, expressed as the nitrate ion that returned a numeric result rather than a result below the detection limit.	%	supply-zone, local-authority, county
`dw-nitrate-exceedance`	Nitrate limit exceedance rate Percentage of drinking-water samples analysed for nitrate, expressed as the nitrate ion whose result exceeded the regulatory limit of 50 mg/l as NO₃.	%	supply-zone, local-authority, county
`dw-lead-concentration`	Lead in drinking water Mean concentration of lead in treated drinking water, computed over quantified samples only.	µg/l	supply-zone, local-authority, county
`dw-lead-quantified`	Lead quantified sample share Percentage of drinking-water samples analysed for lead that returned a numeric result rather than a result below the detection limit.	%	supply-zone, local-authority, county
`dw-lead-exceedance`	Lead limit exceedance rate Percentage of drinking-water samples analysed for lead whose result exceeded the regulatory limit of 10 µg/l.	%	supply-zone, local-authority, county
`dw-pesticides-total-concentration`	Total pesticides in drinking water Mean concentration of the sum of the pesticides analysed in treated drinking water, computed over quantified samples only.	µg/l	supply-zone, local-authority, county
`dw-pesticides-total-quantified`	Total pesticides quantified sample share Percentage of drinking-water samples analysed for the sum of the pesticides analysed that returned a numeric result rather than a result below the detection limit.	%	supply-zone, local-authority, county
`dw-pesticides-total-exceedance`	Total pesticides limit exceedance rate Percentage of drinking-water samples analysed for the sum of the pesticides analysed whose result exceeded the regulatory limit of 0.5 µg/l.	%	supply-zone, local-authority, county
`dw-pfos-concentration`	PFOS in drinking water Mean concentration of perfluorooctane sulfonic acid in treated drinking water, computed over quantified samples only.	µg/l	supply-zone, local-authority, county
`dw-pfos-quantified`	PFOS quantified sample share Percentage of drinking-water samples analysed for perfluorooctane sulfonic acid that returned a numeric result rather than a result below the detection limit.	%	supply-zone, local-authority, county
`dw-arsenic-concentration`	Arsenic in drinking water Mean concentration of arsenic in treated drinking water, computed over quantified samples only.	µg/l	supply-zone, local-authority, county
`dw-arsenic-quantified`	Arsenic quantified sample share Percentage of drinking-water samples analysed for arsenic that returned a numeric result rather than a result below the detection limit.	%	supply-zone, local-authority, county
`dw-arsenic-exceedance`	Arsenic limit exceedance rate Percentage of drinking-water samples analysed for arsenic whose result exceeded the regulatory limit of 10 µg/l.	%	supply-zone, local-authority, county
`drinking-water-sample-count`	Drinking water samples analysed Number of regulatory drinking-water sample results held for a supply area over a period.	samples	supply-zone, local-authority, county

Rights and access

Licence position

Open with attribution. Derivative use true; redistribution true; commercial reuse true.

Attribution required:

Source: Hub’Eau / Système d’information sur l’eau, under Licence Ouverte (Etalab).

Permitted uses

Public display
Derived analysis
API delivery
Bulk download
Commercial use

Available to: Public, Developer, Research, Professional, Enterprise. These follow from the rights of the contributing publishers, not from a Hydrionis pricing decision — no access tier can widen what a publisher withheld.

Contributing sources

Ministère chargé de la santé / ARS — Qualité de l'eau potable — drinking water (Licence Ouverte / Open Licence v2.0 (Etalab))

Suggested citation

Hydrionis (2026), France Drinking Water Quality Dataset, version 1.0.0. Retrieved from https://hydrionis.com/data/datasets/france-drinking-water-quality/

Cite the version. Hydrionis datasets change as publishers release and as methods are revised, and a citation without a version cannot be checked later.

Changelog

Version 1.0.0 — 2026-08-25

First release. Hydrionis holds drinking-water observations for the first time.

Additions

Determinand statistics by department for five determinands.

Getting the data

drinking-water observations from Hub'Eau / SISE-Eaux (4,855 rows) (CSV)

Machine-readable metadata for this dataset is at /api/v1/datasets/france-drinking-water-quality.json. For bulk extracts, higher-volume access or commercial licensing, see data enquiries.