Overview
- The Öko‑Institut, commissioned by Greenpeace, estimates German data centers used about 13 billion liters of water for cooling in 2025 and that planned 'mega' sites could raise annual demand to as much as 27 billion liters by 2030.
- For a single 100‑megawatt facility the study finds cooling needs ranging from roughly 200 million to 930 million liters per year, a volume comparable to the drinking water use of a small town and a clear risk for dry regions.
- Reporting gaps make oversight weak: of roughly 1,200 facilities required to report, only 482 submitted 2025 consumption figures and just 139 datasets passed plausibility checks, leaving regulators with limited reliable data.
- Major operators such as Equinix, NTT and CloudHQ have refused to publish site‑level consumption, citing business secrecy, and a proposed amendment to the Energy Efficiency Act would formally broaden exemptions from disclosure.
- The Öko‑Institut finds no statistical link between higher energy efficiency and greater water use and notes modern dry or compression cooling can remove direct water loss, while Greenpeace urges mandatory water impact assessments, regional bans on water‑intensive builds and sanctions for bad or missing reports.