Water use should not be high on the list.
Water use should absolutely be high on the list since much of the world's population is increasingly water starved. Even in places known for endless rain we are experiencing droughts, river level variation not seen previously, and water table droppage.
We can't stop pouring water on farms. That provides food to eat. But we can absolutely mandate the end of the use of evaporative cooling for datacentres which is not only a significant water consumer, but something we do largely only for cost avoidance rather than absolute necessity.
39 milliliters of water per a typical query.
You say this as if this isn't a fucking scary number considering a typical query. Given you can't type something into Google these days without a query being generated, and that a typical conversation with ChatGPT can literally run from the 10s to the 100s of queries comparing it to a shower which you do once a day is just absolutely mind-blowingly silly. On top of that humans don't last long without basic sanitation, but we've somehow made it through the entire rise of civilisation without Gemini giving me an AI generated preview of something I could click on anyway. Showering isn't wasting water. AI is.