Seems like you can actually be "starved" of things other than food...
- To suffer or die from extreme or prolonged lack of food.
- Informal To be hungry.
- To suffer from deprivation: a puppy starving for attention.
"Starved for attention" as in the third definition above, or "starved of oxygen" for example.
So, as in this article, they use "starved of water" to mean being deprived of water:
One in eight dying patients are starved of food and water in their final days of NHS care.
And this book uses "water-starved" as part of its title... surely a book about being starved of water would have found an official word if there were one:
Let There Be Water: Israel's Solution for a Water-Starved World
So, for the sake of your request, it seems like "water-starved" is a good choice.