For some numbers:
One graph even has California's animal feed water usage so large it actually goes off the chart at 15.2 million acre-feet of water (it is distorted to make it fit as it notes). For some comparison, the blue water usage of animal feed is larger than all of almonds water usage of ~2 million acre-feet of water
https://pacinst.org/wp-content/uploads/2013/02/ca_ftprint_full_report3.pdf#page=25
EDIT:
If the image isn't loading for you, here's a direct link: https://i.imgur.com/EjVps9Z.png
EDIT 2:
Also worth noting is that per liter, dairy milk requires 628.2 L of freshwater vs almond milk requiring 371.46 L of freshwater. And if you use something like oat milk instead that gets you to 48.24 L
Animal feed is a huge category, vs. almonds. Almonds registering on that scale is what's so shocking about it.
Edit: Not that it isn't wasteful, if you need extra feed besides grazing, you're in trouble ecologically.
The water usage per liter of dairy milk is also higher. Per liter, dairy milk requires 628.2 L of freshwater vs almond milk requiring 371.46 L of freshwater. And if you use something like oat milk instead that gets you to 48.24 L.
https://ourworldindata.org/environmental-impact-milks
Keep in mind here that 80% of the entire world's almonds are grown in California, so it's not surprising its a decent large user by size. Even despite that, just the mostly US demand for animal feed dwarfs water usage in California
https://en.m.wikipedia.org/wiki/Almonds_in_California
This is the mode important metric, thanks for including it