Coffees and teas are made from plane tap water that could contain coliform, bacteria found in 12% of commercial airplanes, according to a 2012 EPA report. Because coliform comes from feces, where harmful bacteria also lurk, water that contains it is more likely to harbor scarier stuff like E. coli, which can really mess with your system. So don&#x27;t risk it: Opt for bottle water instead and hold the ice  if it&#x27;s made with plane tap water. (Just ask an attendant.)