WASHINGTON, D.C.
A new study has raised serious concerns over the quality of drinking water on U.S. flights, prompting health experts to advise travelers to be cautious about consuming tap water at 30,000 feet. The comprehensive research, conducted by the Center for Food as Medicine and Longevity, analyzed water samples from 21 U.S. airlines, including both major and regional carriers, over a three-year period from October 2022 to September 2025.
Investigators tested tens of thousands of samples drawn from aircraft galleys, lavatories, and other potable water sources, checking for bacterial contamination, coliform presence, and adherence to standard disinfecting practices. According to the study, while some airlines maintained high safety standards, several others fell short, highlighting inconsistencies in onboard water management.
Major carriers such as Delta Air Lines and Frontier Airlines received top marks for water safety, showing minimal contamination and rigorous maintenance routines. Airlines including Alaska, Allegiant, and Southwest also performed reasonably well. However, American Airlines and JetBlue were flagged for low water safety scores, and regional carrier Mesa Airlines received the lowest overall grade in the study.
Health officials emphasized that even occasional contamination could pose risks, particularly for vulnerable passengers with compromised immune systems. A measurable portion of samples contained coliform bacteria, which may indicate the presence of other harmful organisms. In rare cases, traces of E. coli were also detected, raising further concern.
Onboard aircraft, water is stored in tanks and must be flushed and disinfected regularly under the U.S. Environmental Protection Agency’s Aircraft Drinking Water Rule (ADWR). Researchers noted that lapses in these routines, as well as prolonged tank inactivity, could create conditions favorable to bacterial growth. Experts stress that while most passengers may not experience illness, caution is warranted.
Flight attendants and frequent travelers have shared anecdotal evidence of inconsistent water quality. They recommend opting for sealed bottled water, and note that beverages like coffee and tea are typically safer because they are prepared with boiled water. Some passengers have adopted additional precautions, including using hand sanitizer instead of washing with aircraft water.
The study has renewed calls for stricter oversight and enforcement of existing federal regulations. Experts argue that ensuring safe onboard water is as important as air filtration and food safety in maintaining overall passenger health. As the airline industry continues to rebound from pandemic-related disruptions, attention to sanitation practices, including water quality, remains critical.
For passengers, the takeaway is clear: when in doubt, choose bottled beverages and exercise caution with tap water onboard. While many airlines maintain safe drinking water, the documented variability underscores the importance of being proactive about hydration and health during air travel.
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