Tap Water (Including in Coffee and Tea) As T+L previously explained, the water tanks on planes are notoriously grimy. A 2004 EPA sample of 158 planes found that 13 percent contained coliform, and two had dangerous levels of E. coli. Fogwell added, don't be fooled by a water pitcher either.

The primary reason experts and flight attendants advise against drinking airplane coffee in 2026 is water hygiene. A major 2026 report found that many aircraft water tanks—which supply the galleys for coffee and tea—test positive for coliform bacteria and occasionally E. coli. Unlike bottled water, the water in these tanks is rarely cleaned or completely drained. Furthermore, the brewing temperature on a plane is often lower due to the reduced boiling point at cabin altitude, meaning it may not reach a temperature high enough to kill all microorganisms. For 2026 travelers, the "safest" bet is to stick to sealed bottled water or canned drinks. If you absolutely need caffeine, many "pro-travelers" now bring their own instant coffee and ask the crew for a cup of bottled hot water to avoid the mystery tank water entirely.