Many years ago, while in the field studying pyros. This biologist(non herp) brought up this subject. So I tested it.
I raised up hatchling pyros without any drinking water. I made a subfloor and had vermiculite and water under it. substrate above. Not vents, only a couple of holes. 1/8 inch.
Out here in the desert, most snakes rarely drink. Its rare.
a friend in phoenix, regularly records crots coming out and drinking. Here, I have seen snakes drink, maybe a handful of times over many many years.
I also have a really funny tort story, about drought/water and food.
Back to the kings, they grew well, fed well etc.