Is the water on an airplane safe to drink?

Aircraft potable water is regulated under the EPA's Aircraft Drinking Water Rule, which requires periodic testing and disinfection. Compliance testing has nonetheless found coliform bacteria in a meaningful share of aircraft over multiple survey rounds, and the underlying difficulty is structural: water sits in onboard tanks, the fill equipment at airports varies in cleanliness, and the plumbing is not easy to flush thoroughly between services. The practical guidance from that record is to drink bottled or canned beverages and skip anything drawn from the galley tap.

Coffee and tea are the part people miss. Water for hot drinks comes from the same tanks, and galley equipment does not reach or hold a temperature high enough to reliably sterilize contaminated water, so hot does not mean safe here. The same reasoning applies to washing hands in the lavatory, where hand sanitizer afterward is a reasonable habit. Two adjacent flight-health notes worth knowing: cabin humidity typically runs below 20 percent, which is drier than most deserts and is the main reason you feel dehydrated and your sinuses hurt, making the argument for drinking plenty of the bottled water rather than skipping fluids entirely. And cabin air itself is generally cleaner than expected, since it passes through HEPA filtration and is exchanged frequently, so air quality is not the concern; the tray tables and the water are.