Data centers and water in France: what the law says, and what to check on the ground

"Will a data center take our water?" It is one of the first questions asked at public meetings. The answer depends less on national figures than on three local factors: the cooling technology, where the water comes from, and the state of the resource at the project's location.

DOES YOUR SITUATION LOOK LIKE ONE OF THESE?

Residents are asking us about the water use and noise of the future data center. We have no figures to give them.A national newspaper article lists our project among the "data centers drying out France".The public pre-consultation opens in three weeks, and an association is organising a public meeting against the project.

Francis Gillard
Data center design & auditsTalk to Francis →

Blandine Cazelles
Crisis communication & public affairsTalk to Blandine →All situations →

1. HOW MUCH WATER DATA CENTERS USE IN FRANCE

At national level, this volume is modest. But a national average says nothing about a given site: a large data center cooled by evaporation, on a resource already under pressure in summer, can matter locally. That is the point local authorities and residents are right to check.

2. THE RULES THAT APPLY

If the site is supplied by the public drinking water network, as most are, the issue is first settled with the water utility: network capacity, the supply contract, and compliance with restrictions set by the prefect during droughts.

If the site draws water itself from an aquifer or a river, French water law applies. Below 1,000 m³ a year, the withdrawal counts as domestic use. Above that, the nomenclature sets the thresholds:

Evaporative cooling towers also fall under the classified installations regime, in particular for legionella prevention.

Building permits. Law no. 2026-403 of 26 May 2026 allows the authorities to refuse the building permit of a data center located in an area with "structural tensions on water resources". It is an option, not a ban, and the law does not define the notion. The Conseil d'État had already accepted, in December 2025, that a mayor may refuse a permit on grounds of insufficient water resources.

Transparency. Data centers above 500 kW already report their water consumption to the EU database, with their other indicators. See the EU data centre rating.

3. WHAT DRIVES CONSUMPTION

Dry coolers and closed loops use very little water but more electricity. Adiabatic or evaporative systems save electricity but use water, especially during heatwaves, when the resource is scarcest. The choice is a trade-off between water and power, which should be explained, quantified and owned.

4. A FREQUENT QUESTION: "INDIRECT" WATER

Power generation, nuclear in particular, also withdraws and evaporates water. It is not counted in data centers' reported consumption. Some argue it should be included in their footprint; others point out that this water produces electricity for every use, and that allocating it to data centers alone raises methodological questions. The debate is legitimate; it benefits from sourced figures.

5. WHAT TO ASK A PROJECT DEVELOPER

A project that answers these questions clearly before public consultation avoids most disputes on the subject. See also cooling with quarry and mine water.

Sources: Arcep, annual survey "Pour un numérique soutenable", 2026 edition (2024 data), 21 May 2026; Law no. 2026-403 of 26 May 2026, article 35, and commentaries by Gossement Avocats and Kohen Avocats; French water law nomenclature (headings 1.1.2.0 and 1.2.1.0). This article is general information, not legal advice.

FREQUENTLY ASKED QUESTIONS