A 2026 Airline Water Study released today by the Center for Food as Medicine and Longevity reveals that the quality of drinking water varies significantly by airline, and many airlines continue to provide passengers with potentially unhealthy water.
Unhealthy water violates the federal government’s Aircraft Drinking Water Rule (ADWR), which was implemented in 2011 and requires airlines to provide passengers and flight crew with safe drinking water.
The 2026 Airline Water Study ranks 10 major and 11 regional airlines by the quality of water they provided onboard flights during a three-year study period (October 1, 2022 through September 30, 2025). Each airline was given a “Water Safety Score” (5.00 = highest rating, 0.00 = lowest) based on five weighted criteria, including violations per aircraft, Maximum Contaminant Level violations for E. coli, indicator-positive rates, public notices, and disinfecting and flushing frequency. A score of 3.5 or better indicates that the airline has relatively safe, clean water and earns a Grade A or B.
“Delta Air Lines and Frontier Airlines win the top spots with the safest water in the sky, and Alaska Airlines finishes No. 3,” says Charles Platkin, PhD, JD, MPH, director of the Center for Food as Medicine and Longevity.
The airlines with the worst score are American Airlines and JetBlue, the study shows. “Nearly all regional airlines need to improve their onboard water safety, with the exception of GoJet Airlines,” Platkin says.
The ADWR requires airlines to take samples from their water tanks to test for coliform bacteria and possible E. coli. Airlines are also required to disinfect and flush each aircraft’s water tank four times per year. Alternatively, an airline may choose to disinfect and flush once a year, but then it must test monthly.
The 2026 Airline Water Study also finds that the Environmental Protection Agency – one of the federal agencies responsible for ensuring safe aircraft drinking water – rarely levies civil penalties to airlines in violation of the ADWR.
Here are the study’s findings:
The major airlines receiving the highest Water Safety Scores are Delta Air Lines (5.00, Grade A) and Frontier Airlines (4.80, Grade A). Alaska Airlines is a close third at 3.85 (Grade B).
GoJet Airlines is the highest-rated regional carrier with a score of 3.85 (Grade B).
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