"I wish to drink water."
Translation:Yo deseo beber agua.
I want to drink water would be a better translation. However, I think that deseo is a very strong want, desire, or wish. So, it means you're EXTREMELY thirsty.
BalaClark. Just wondering if you mean "I hope to drink water" I expect to drink water" ; if so I'm espero/espero que is a good choice. Perhaps you have something else in mind.
Dtucker - quiero in this context would be 'want'. It's also used elsewhere to say 'love' regarding a person. I am not aware of quiereo que as being used for 'wish'. It too can mean 'want' and I believe you would use it when you want to emphasis strongly that you want something. Desear is the verb for wish as presented.