Water investigation 01

The water is going in circles.

NVIDIA says its Rubin reference design recirculates coolant in a closed loop. In favorable climates, dry cooling can bring direct on-site cooling consumption near zero. Berkeley Lab’s national estimates describe the mixed U.S. fleet in 2023.

Inspect the conversion

Official conversion desk

One nut acre equals 21 billion AI prompts.

The division works. The comparison doesn’t.

4.49acre-feet per crop acre-yearCalifornia almonds + pistachios category, 2015

1.233Bmilliliters per acre-footU.S. Geological Survey conversion

0.26milliliters per promptMedian Gemini Apps text prompt, May 2025

21.3Bprompt equivalentsA conversion, not an environmental ranking

Panic

California farms are using enough water to ask AI twenty-one billion questions per acre and refusing to share the answers.

Actual fact

It divides a 2015 estimate for one California almond-and-pistachio acre by Google’s 2025 median text-prompt estimate. Different product, year, place, and accounting boundary. Google’s number estimates direct consumptive cooling water, not training or upstream electricity water. The result does not tell you which one strains a particular water supply.

Choose your winner

Almonds lead overall. Pistachios lead in surface and groundwater.

Change the water category and the headline changes with it.

Crop productTotal footprint (green + blue + grey)Blue water consumedRecord note

Shelled almondsTotal footprint16,095 L/kgBlue water3,816 L/kgHigher global-average total

PistachiosTotal footprint11,363 L/kgBlue water7,602 L/kgAbout twice the blue-water component

Actual fact: These are global averages for 1996–2005. Total water combines green rainwater, blue surface and groundwater, and grey water associated with pollution. They are not current meter readings from California almond or pistachio farms.

What moves where

Three different water numbers keep getting called “water use.”

Coolant in the loop, water consumed on-site, and water consumed at power plants are not interchangeable.

Coolant in the loop

Water and glycol carry heat away from chips, pass through a heat exchanger, and circulate again. The loop is filled, not continuously consumed.

Water consumed on-site

Evaporative cooling towers consume water by releasing it to the air. Dry coolers can sharply reduce that loss, with climate and facility design setting the result.

Water behind the electricity

Power generation can consume water elsewhere. Berkeley Lab modeled nearly 800 billion liters for U.S. data-center electricity in 2023, allocated by regional grid mix.

66B LModeled direct on-site consumption, U.S. fleet, 2023

≈0Potential on-site cooling consumption for Rubin dry-cooling designs in favorable climates

Both can be true. One describes a national installed fleet. The other describes a newer manufacturer reference design.

Source records

Check every denominator.

01Berkeley Lab, 2024 U.S. Data Center Energy Usage Report2023 direct and electricity-related water estimates 02NVIDIA, 45°C liquid-cooling architectureClosed-loop Rubin design and favorable-climate dry cooling claim 03Google, Measuring AI at Google ScaleMay 2025 median Gemini Apps text prompt 04UC ANR using California DWR data2015 agricultural water intensity by crop category 05U.S. Geological Survey, definition of termsOne acre-foot equals 1,233 cubic meters 06Water Footprint Network, Report 47Global crop-product averages and green, blue, grey water categories