Are water & snacks allowed to be brought in?

They are Ok with light snacks etc when they inspect your bags. They don't want people to bring in full meals/large coolers etc.

You can bring food, just no giant or rolling coolers. A backpack or lunch box is fine. We bring picnic lunches all the time. There are also water bottle refilling stations by some bathrooms so we bring our own water bottles.

There is probably some rule against bringing snacks in, but its super easy to just hide them in your back pack. Water you can bring, without needing to hide it away.

It's pretty easy to bring water and snacks in your back pack

Water: yes. Snacks: no.