I never really thought of getting a water while on the plane. I usually bring my own and just get the free soda. It’s not just the water you have to worry about but also coffee or tea or anything that water is mixed with on the plane. They are not using the water bottles but the faucet to get that water and apparently some airlines have bad water. They even mention that when washing your hands you should not use the sinks in the bathroom but hand sanitizer instead.
Allegiant Airlines and Alaska Airlines actually have a perfect score when it comes to their water.