- American and Mesa Airlines ranked at the bottom for aircraft water safety.
- The study team advises skipping coffee and tea made with onboard tap water.
- Using hand sanitizer may be safer than washing with airplane sink water.
A major new analysis of onboard airline water quality gives travelers a reason to think twice before drinking a cup of coffee at 35,000 feet. According to the 2026 Airline Water Study from the Center for Food as Medicine & Longevity, some carriers consistently scored poorly on safety indicators, while others performed markedly better.
One big finding is that American Airlines ranked last among major airlines, with JetBlue and Spirit also near the bottom. The findings reinforce long-standing hygiene advice that travelers may want to rely on hand sanitizer after using the lavatory and skip beverages made with onboard tap water when possible.
How Was the Study Conducted?
The researchers analyzed more than 35,000 water samples collected from aircraft galleys and lavatories on 21 major and regional airlines between October 2022 and September 2025. They also reviewed federal compliance records under the Aircraft Drinking Water Rule, bacterial testing data, airline disinfecting practices and public notices to evaluate how consistently airlines met basic water safety expectations.
Each airline received a Water Safety Score on a scale from 1 to 5, with higher scores reflecting stronger compliance histories, more consistent testing records and better disinfection practices. These scores were then converted into letter grades to make the results easier for travelers to understand.
What Did the Study Find?
The results showed wide differences between airlines. Delta Air Lines earned the highest overall score, receiving a perfect 5.00 and an A grade. Frontier Airlines followed closely with another A grade, while Alaska Airlines placed in the upper tier with a B grade.
At the opposite end of the list, American Airlines ranked last among major carriers with a D grade and the lowest overall score of 1.75. JetBlue and Spirit Airlines also landed near the bottom with similarly low scores. Among regional carriers, GoJet Airlines performed relatively well while Mesa Airlines received the lowest score overall of 1.35. The study’s authors also noted that some of the lowest scoring airlines had histories of compliance violations.
How Does This Apply to Real Life?
For travelers, the findings suggest that caution is still warranted when it comes to onboard tap water. Although airlines are required to test and disinfect aircraft water systems, tanks can sit stagnant between flights and water quality can vary based on how planes are serviced at different airports.
Because of this, the study’s authors advise passengers to avoid drinking any unsealed onboard water, including coffee and tea prepared with onboard water. Using hand sanitizer after using the lavatory is also widely recommended, since sink water may not meet the same standards as municipal tap water on the ground. Purchasing bottled water after passing through security is the most reliable option for staying hydrated during a flight.
Our Expert Take
This study highlights a long-standing blind spot in air travel safety. Aircraft water systems are complex, and even airlines with higher scores are not testing water in real time on every flight. A strong compliance history doesn’t guarantee that every tank on every plane is as clean as you might like.
From a practical standpoint, onboard tap water should be treated as a less dependable source than sealed bottled water. Planning ahead for hydration, avoiding beverages made with aircraft water and using personal hand sanitizer are simple steps that can reduce unnecessary exposure and give travelers more control over their in-flight well-being.
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