Wallonia Blocks Google's River Cooling Permit for AI Data Center Over Drought

Wallonia’s denial of Google’s permit to use Sambre River water for AI data center cooling is a regulatory signal that water rights for hyperscalers are no longer guaranteed, even with a massive investment on the line. The decision used existing EU environmental law, not new legislation, to block 600 cubic meters per hour of river withdrawal during a severe drought.

The permit and the appeal that stopped it

On August 14, Walloon Vice-Prime Minister François Desquesnes refused Google’s modified permit to pump 600 cubic meters per hour (roughly 159,000 gallons per hour) from the Sambre River for evaporative cooling at its second Ecopôle data center. Under Google’s plan, only 25 percent of the water would have been returned to the river, at a temperature of 30°C. The remaining 75 percent would be lost to the atmosphere through evaporation.

Google’s original permit for that facility specified air cooling, matching the first data center already nearing completion on the same site. At some point during the process, Google applied to modify the permit to switch to river-water-based evaporative cooling. The Walloon waterways administration reviewed the request and granted approval. That approval was then challenged by a private citizen filing a standard administrative appeal, which transferred the final decision to the minister. Desquesnes invoked the precautionary principle, stating that he could not commit to allocating water whose future availability is deeply uncertain as climate change advances.

Why this matters for AI builders

This is not a narrow permitting dispute. It establishes a template: any EU regulator facing drought conditions, an existing environmental permit, and a concerned citizen can deny a hyperscaler’s water-cooling plan without passing new laws. The EU’s Energy Efficiency Directive requires large data centers to report water consumption annually, but it does not cap withdrawals. Wallonia’s ruling goes further by imposing a real-time resource limit grounded in present drought and future climate projections.

For teams building or deploying AI infrastructure in Europe, this has direct implications. Evaporative cooling achieves Power Usage Effectiveness (PUE) ratios as low as 1.05, compared to 1.4-2.0 for conventional air conditioning. That efficiency is hard to give up, especially for AI workloads dominated by GPUs running continuous inference and training at rack densities approaching 50 kilowatts per rack or higher. But as water permits become conditional on hydrological conditions, hyperscalers will need to budget for more expensive cooling strategies.

What changes practically

Google now has two formal options: revert to the original air-cooling design or appeal to Belgium’s Council of State, a process that could take years. Mayor Grenier of Aiseau-Presles has suggested a third path: alternative water sourcing such as large-scale rainwater harvesting or partial evaporative recapture, both of which add significant engineering cost compared to direct river abstraction.

The industry is already moving toward closed-loop systems that eliminate continuous water withdrawal. Microsoft’s Fairwater campus in Wisconsin uses a closed-loop design that fills once at construction and never requires replenishment. Nvidia’s June 2026 DSX reference design targets near-zero on-site water consumption for Rubin-generation data centers through 100 percent liquid cooling in a closed loop. Wallonia’s ruling adds regulatory urgency to that transition.

Caveats to keep in mind

The decision applies to a modified permit for one facility; Google’s first Ecopôle data center, which uses air cooling, is unaffected. The source reporting is a single TechTimes article, and the regulatory landscape may evolve. Still, the mechanism used here is available to any EU regulator right now, which makes this more than a local footnote.