The water that airlines use to make coffee and tea and the water from the faucet in the airplane bathroom could be unhealthy, according to the Center for Food as Medicine and Longevity’s 2026 Airline Water Study, which was released last month. The study ranked 10 major and 11 regional U.S. airlines based on the quality of water they used aboard their flights, including whether or not the water tested positive for E. coli and coliform bacteria.
“Unlike municipal water systems with continuous flow and regular monitoring, aircraft water systems experience periods of stagnation between flights, temperature variations during ascent and descent, and mechanical stress from aircraft operations. These conditions can create environments conducive to biofilm formation and microbial proliferation,” the study stated.
It noted that the water loaded onto airplanes comes from airports with a wide range of infrastructure, “and contamination introduced during the servicing process—whether from hoses, truck tanks, or improper handling—can persist in aircraft systems if adequate disinfection and flushing protocols are not rigorously maintained.”
Only three major airlines—Delta Air Lines, Frontier Airlines, and Alaska Airlines—were reported to have relatively clean water, even though the U.S. Environmental Protection Agency’s Aircraft Drinking Water Rule (ADWR) requires that safe and reliable drinking water be provided to aircraft passengers and crew.
The 2026 Airline Water Study analyzed ADWR records submitted to the EPA between October 1, 2022, and September 30, 2025.
The study found American Airlines and JetBlue were the worst offenders among the major airlines. “Nearly all regional airlines need to improve their onboard water safety, with the exception of GoJet Airlines,” Charles Platkin, director of the Center for Food as Medicine and Longevity, stated in the report. (GoJet Airlines is a regional carrier based in St. Louis that flies to Chicago, Washington, D.C., and Newark, New Jersey.)
The report advises passengers never to drink any water on board that isn’t in a sealed water bottle, not to drink coffee or tea on board (as it’s made using the water stored in potentially contaminated aircraft tanks), and to use alcohol-based hand sanitizer containing at least 60 percent alcohol instead of washing your hands with water.
The report also suggested that fliers take additional precautions on international routes because practices for refilling aircraft water tanks can vary even more globally. If you must use the aircraft tap water, then let it run for about 30 seconds before washing your hands, to flush stagnant water from the lines.
Here’s how the airlines in the study stacked up, on a scale of 0 to 5, with 5 indicating the highest water quality.
Airline water safety scores
Major U.S. airlines
- Delta Air Lines: 5.00
- Frontier Airlines: 4.80
- Alaska Airlines: 3.85
- Allegiant Air: 3.65
- Southwest Airlines: 3.30
- Hawaiian Airlines: 3.15
- United Airlines: 2.70
- Spirit Airlines: 2.05
- JetBlue: 1.80
- American Airlines: 1.75
Regional U.S. airlines
- GoJet Airlines: 3.85
- Piedmont Airlines: 3.05
- Sun Country Airlines: 3.00
- Endeavor Air: 2.95
- SkyWest Airlines: 2.40
- Envoy Air: 2.30
- PSA Airlines: 2.25
- Air Wisconsin Airlines: 2.15
- Republic Airways: 2.05
- CommuteAir: 1.60
- Mesa Airlines: 1.35
What is the risk, really?
First off, let’s tackle what coliform bacteria and E. coli are and what kind of risks they pose. Coliform bacteria are microbes that typically don’t make you sick, according to the U.S. Centers for Disease Control and Prevention (CDC). But if there’s a high level of these microbes in, say, water, there could be harmful germs like viruses, bacteria, and parasites present.
It’s a similar story with Escherichia coli (E. coli), a bacteria that’s typically harmless. But some strains of E. coli can cause stomach illness and are transmitted through contaminated water or food, the CDC reports.
“The potential health consequences of consuming contaminated aircraft drinking water range from acute gastrointestinal illness to exposure to opportunistic pathogens. Vulnerable populations, including young children, elderly passengers, pregnant women, and immunocompromised individuals, may face elevated risks from waterborne pathogens,” the Center for Food as Medicine and Longevity’s report stated.
While we know that airlines reported traces of coliform bacteria and E. coli in their water, what we don’t know is how much or what kinds.
“Fortunately, most coliform bacteria and E. coli are harmless and are not capable of causing illness. However, the presence of such bacteria in water can be an indicator that the water is not pure or has become contaminated,” says Dr. William Schaffner, professor of preventive medicine at Vanderbilt University and an infectious-diseases expert. “In light of these findings, it seems prudent to avoid these sources of water on airlines.”
Best practices for in-flight health and hygiene
The 2026 Airline Water Study concluded that travelers should not drink any water on a flight that isn’t from a sealed bottle; that they shouldn’t drink the coffee or tea served on board; and that they shouldn’t wash their hands in the bathroom but should instead use hand sanitizer.
“In recent years, I’ve always been given bottled water when I’ve traveled—that avoids [that] problem,” says Schaffner. As for safety concerns regarding coffee and tea, he says, “Coffee and tea also ought to be safe as those hot temperatures should kill the bacteria in the water.”
Still, if you’re nervous about the possible health risks of drinking water that comes from the aircraft tanks, you can pass on the coffee and tea (maybe bring bottled cold brew or iced tea on board instead) and stick to bottled water or other bottled or canned beverages. But is it really better to skip washing your hands after using the restroom?
Schaffner suggests that fliers can wash their hands and then use hand sanitizer afterward if they want to be extra vigilant. He adds, “Persons who are health-oriented may also choose to use alcohol-based wipes for hand hygiene while on airplanes.”
According to the CDC, you should use an alcohol-based hand sanitizer that contains at least 60 percent alcohol for it to be effective.
What’s next for airplane water?
The Center for Food as Medicine and Longevity’s 2026 study comes seven years after the Hunter College NYC Food Policy Center released a 2019 Airline Water Study that came to a very similar conclusion about water used on airplanes.
Consequently, the 2026 study outlines several steps it hopes to see airlines and the EPA take, including routine monitoring and testing of aircraft water samples for the presence of total coliform bacteria and E. coli; disinfection and flushing when contamination is discovered; and improved record-keeping and reporting by the EPA.
Shalini K. Narang contributed reporting. This story was initially published in November 2019 and was updated on February 25, 2026, to include current information.
