Over time one learns to adapt, via what one eats such, that I don't require more access to a bathroom than the average person.

A water bottle with built in filter can easily provide enough safe water onboard the plane without causing medical complications or requiring constant attention from the FAs, even if one must drink water from the tanks.

TSA has a major job to do and it's hard to predict where the terrorists are going to find the next major hole. My only problem would be if TSA does not allow me to carry an empty water bottle on the plane. And I usually fly on transcontinental flights.