Is it normal / legal for Houston libraries to ban patrons from drinking water?

Preparing to get downvoted for this, but I didn’t know where else to ask and I’m just surprised. I was recommended by a friend that works downtown to go visit Julia Ideson library because I had to get some quiet studying done. So I got my coffee thermos and went up ready to work. Beautiful building! But after I got in and set up, the security guard woman got very rude and said “I didn’t see you brought in a beverage, no beverages are allowed”. I asked if a water was okay, and she said no. I couldn’t find a drinking fountain either.

I guarantee she and all of the employees there bring in both, and I also found that they have huge weddings and events in that same room regularly, cocktails splashing around and all.

Which got me to thinking – is it perfectly legal for a public sector building to ban you from drinking water (literally throughout the entire building, her words)? If they don’t provide any? And is this normal for public libraries in Houston?

EDIT: I should clarify, this is outside of the listed houston library policies online, which specify that you can drink inside within a few simple boundaries. This building flat out banned swallowing liquids lol