About data centers

Cooling

Water use is a cooling choice, not a law of AI. Evaporative towers dump water to air. Closed-loop liquid cooling fills once and recirculates. Seawater and heat reuse are the other two exits. The existing fleet still mixes all of these.

Evaporative

Water is sprayed or run over fill. Some evaporates. That is consumption. Alphabet, year ended 31 Dec 2025, EY-reviewed 22 Jun 2026: Council Bluffs consumed 1,346 million gallons. The Dalles consumed 469 million gallons. Same company, same year, cooling towers.

Alphabet Inc., Schedule of Water Use by Data Center Location, year ended 31 Dec 2025, EY-reviewed 22 Jun 2026.

Closed loop

Fill at construction. Water, or water and glycol, runs through the chips, hits a heat exchanger, and comes back. No evaporation in normal operation.

Microsoft, Steve Solomon, 9 Dec 2024: chip-level closed loop, zero water evaporated for cooling. More than 125 million liters avoided per datacenter per year, about 33 million gallons, is Microsoft's design estimate from FY2024 WUE, not a meter. Kitchens and restrooms still use water. New designs from Aug 2024. Phoenix and Mt. Pleasant are pilots and design, not live proof of zero-water cooling. Nominal extra electricity versus evaporative.

Microsoft, Steve Solomon, 9 Dec 2024.

Microsoft Source, 23 Jun 2026: the first Mount Pleasant building is operational. That release does not say it runs the zero-water design.

Microsoft Source, 23 Jun 2026. Operational building, not proof of zero-water cooling.

Microsoft WUE 0.30 L/kWh last fiscal year, down from 0.49 in 2021, is the mixed fleet in that year, not the new closed-loop kit.

Meta, 2026: a majority of newest AI-optimized halls use closed-loop water and glycol. The coolant is expected to last up to a decade.

Meta, closed-loop cooling, 2026.

Seawater and reuse

Alphabet's schedule excludes seawater returned to the sea. Hamina consumed 0.4 million gallons of freshwater in 2025.

Google and Haminan Energia, 20 May 2024: recovered heat into the town network, free except €1 + VAT. Haminan Energia said then it would cover 80% of annual district demand. That is a 2024 statement. There is no measured 2026 operating share on this page.

Alphabet schedule, year ended 31 Dec 2025. Hamina freshwater.

Google and Haminan Energia, 20 May 2024. The 80% figure is that 2024 statement, not a measured 2026 share.