In 5e, like in many others, there’s spells like a druid’s create or destroy water (lvl 1), hero’s feast (lvl 6), and a cleric’s create food and water (lvl 3).
For the Dark Sun setting, in game terms there’s merit in removing these spells or bumping the levels or restricting them to druids and water clerics.
In novel terms they are essential. For sure not the silly part of calling forth food like one is at Hogwarts, but the calling forth of life-giving water. We see that in Brazen Gambit with Quraite.
So how can a non-druid, non-cleric of water spellcaster go about calling forth water?
Surely a wizard can pull it off with wish through its “duplicate any other spell of 8th level or lower” use?
They should take up psionics like the rest of Athas and give up vile spellcasting all together for the good of Athas! =P
What about Sustenance, the psionic (or magical, sigh) version? Seems like that would become a survival mutation… those that have and/or share it survive, those that don’t perish. Not to mention Photosynthesis as a possible alternative.
Druid’s with water chosen as one of their elements, water clerics, and templars can create water. Yes, a wish spell could as well, but that’s it.
They are restricted. 1/2 gallon per level, no more.