I'm 20 years old, so not too long ago was I in school
All of these were in the Chicago Public School system.
In my first elementary school, we were allowed water bottles only during June. Same goes for my second elementary school. In high school , we were also only allowed water bottles in June (officially, aka announcement) but some teachers allowed them at all times of the year. I had one teacher who allowed snacks as long as they were somewhat healthy (aka not flamin' hot cheetos).
I was the rebellious one and snuck pretzels into class in my backpack
So- to answer your question... only in June. As far as I know (according to my SIL who is still in high school [a different CPS High School] this remains the same).