Everything that you buy at the airport is marked up at least a billion percent. That includes water. And since the days of stronger TSA screening are still upon us, we are not allowed to bring anything in past security. That is why I am so grateful for these new water bottle filling stations that are popping up all over the airports in the US. Now you can fill your bottle all the way up for free instead of a partial filling at a traditional water fountain or spending all of your vacation money on a bottle of water once you pass through security. Now if we could only get Europe to follow suit... The only place I've seen with a water bottle filling station is Budapest's airport and it was hidden upstairs in the bathrooms by the back.