No medical personnel I have asked have an answer to this. Any non-carbonated water (Perrier is an exception) from the highest quality to the lowest, makes me nauseous. I can get down about 8-12 ounces without wanting to throw up, but that’s it. I can drink any other liquid without any problems (except for milk, which tends to have the same effect, but I figure that’s because it’s thick).
8-12 ounces at a time isn’t bad. Chances are, you’re getting what the kids in my neighborhood used to call “water-logged,” which is to say that you’ve just got too much sloshing around going on in your belly. That feeling corresponds in many people to a sense of an impending refund.
WAG quotient of this answer: 38.6%
My WAG would be that it’s a learned response. It happened at some point for an unknown reason (maybe drinking too fast or drinking when you were a little bit ill) and you noticed it and then started looking for it, and now it’s become an association.
Perrier is carbonated. FWIW carbonated drinks will always be more acidic than plain water though I wouldn’t guess that’s the culprit. I’ll throw another WAG out there and say dissolved gasses. I find most plain bottled water to be pretty bland but if you shake the bottle well the agitation will dissolve oxygen into the water and change the taste noticably. Try it.
:smack: I meant to say that non-carbonated water makes me nauseous, but I can drink Perrier because it is carbonated. Sorry.
Could be a learned response; I am a Type I diabetic and when my sugar’s high I get awfully thirsty. Maybe more gasses/oxygen in the water eliminate the puke factor?
The 8-12 ounces at a time is when, about once a month, I try to drink water. The rest of the time I’m like, “Aaaarggggh! Nooooo!” 
Could be the local water? I couldn’t drink the water in Saskatchwan when I lived there. Never had that problem in Australia though.