When we ate small fruits as children and then drank water, we could expect to be reminded by the adults. Because, according to the opinion at that time, drinking water on fruit causes bad abdominal pain.
Fruit and water are well digestible
As far as this warning of our well-meaning parents or better grandparents is concerned, the Federal Research Center for Nutrition gives the all-clear. This says namely, the combination of water and fruit is quite well digestible.
Reason: Earlier were in the drinking water allöglichen germs. They brought the fruit in the stomach to ferment, which in turn had the known consequences, namely bloating, stomach ache and diarrhea. Nowadays the water quality is so good that no bacteria are contained in the water. Fruit and water are therefore a "tolerable" couple.