That sure is unusual. It seems that since your body is made up of 70% water --it certainly would not bother you.
Something is going that I don't understand --- I would try a pure form of water like steam distilled to see if it makes ant difference. Maybe something is in the water you drink???
My stomach does better with small amounts and more often. How much do you drink at once, and are you eating with it. Someone mentioned swallowing air along with drinking also.