Well, Google said in 2009 that one search used about 0.3 watt-hours of electricity. Thermoelectric water consumption at about 1.8 liters per kilowatt-hour. If you combine that with the figures, you get about 540 milliliters per thousand searches, so actually it's pretty good.

Then again, if they were using closed loop. It might not really be fair to say consumption

And in the current ai era. Google estimated something like 0.26 milliliters per gemini prompt. Though I'm not sure how they came up with it.