A new study just released by the New York-based nonprofit Center for Food as Medicine and Longevity shows that the quality of drinking water varies significantly by airline—and many airlines are providing passengers with potentially unhealthy water.
The study, which ranks 10 major and 11 regional airlines by the quality of water they provided onboard flights during a three-year period, ranked each by a water safety score, with 5.00 as the highest rating and 0.00 as the lowest rating. It used five weighted criteria: violations per aircraft, maximum contaminant level violations for E. coli, indicator-positive rates, public notices, and disinfecting and flushing frequency. CFML said that 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 number three,” said Dr. Charles Platkin, director of the Center. “Nearly all regional airlines need to improve their onboard water safety, with the exception of GoJet Airlines.”
The federal government’s Aircraft Drinking Water Rule (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 and test monthly.
The 2026 Airline Water Study also found 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.
For passengers, the Center recommends to never drink any water onboard that isn’t in a sealed bottle; not to drink coffee or tea onboard, and not to wash hands in the bathroom—instead, it is preferable to use alcohol-based hand sanitizer containing at least 60% alcohol.
Following are the complete scores from the study:
Major Airlines
- Delta Air Lines: 5.00 (Grade A)
- Frontier Airlines: 4.80 (Grade A)
- Alaska Airlines: 3.85 (Grade B)
- Allegiant Air: 3.65 (Grade B)
- Southwest Airlines: 3.30 (Grade C)
- Hawaiian Airlines: 3.15 (Grade C)
- United Airlines: 2.70 (Grade C)
- Spirit Airlines: 2.05 (Grade D)
- JetBlue: 1.80 (Grade D)
- American Airlines: 1.75 (Grade D)
Regional Airlines
- GoJet Airlines: 3.85 (Grade B)
- Piedmont Airlines: 3.05 (Grade C)
- Sun Country Airlines: 3.00 (Grade C)
- Endeavor Air: 2.95 (Grade C)
- SkyWest Airlines: 2.40 (Grade D)
- Envoy Air: 2.30 (Grade D)
- PSA Airlines: 2.25 (Grade D)
- Air Wisconsin Airlines: 2.15 (Grade D)
- Republic Airways: 2.05 (Grade D)
- CommuteAir: 1.60 (Grade D)
- Mesa Airlines: 1.35 (Grade F)
For the latest travel news, updates and deals, subscribe to the daily TravelPulse newsletter.
Topics From This Article to Explore
