page 21, says Arizona 2015 golf course irrigation was 120 million gallons per day, citing the US Geological Survey.

https://dgtlinfra.com/data-center-water-usage/

says Google's datacenter water consumption in 2023 was 5.2 billion gallons, or ~14 million gallons a day. Microsoft was ~4.7, Facebook was 2.6, AWS didn't seem to disclose, Apple was 2.3. These numbers seem pulled from what the companies published.

The total for these companies was ~30 million gallons a day. Apply your best guesses as to what fraction of datacenter usage they are, what fraction of datacenter usage is AI, and what 2025 usage looks like compared to 2023. My guess is it's unlikely to come out to more than 120 million.

I didn't vet this that carefully so take the numbers with a grain of salt, but the rough comparison does seem to hold that Arizona golf courses are larger users of water.

Agricultural numbers are much higher, the California almond industry uses ~4000 million gallons of water a day.