An excuse to have another beer or glass of wine when flying? A new study emanating from south of the border warns travellers not to drink tea, coffee, or unbottled water on flights, load up on ice, or even clean their hands in washrooms, due to potentially unhealthy water used on board many aircraft.
Notably, the 2026 Airline Water Study by the U.S.-based Center for Food as Medicine & Longevity was limited to U.S. carriers and did not rate Canadian (other international airlines); it further qualifies that water quality varies significantly by airline.
However, based on the study, the Center offers the following “bottom line” advice to travellers (at least, those flying on U.S. airlines):
- NEVER drink any water onboard that isn’t in a sealed bottle.
- Do not drink coffee or tea onboard.
- Do not wash your hands in the bathroom; use alcohol-based hand sanitizer containing at least 60% alcohol instead.
Released this week, the study ranked 10 major and 11 regional airlines by the quality of water they provided onboard flights during a three-year study period (Oct. 1, 2022, through Sept. 30, 2025).
In the study, 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.
Major study 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).
- Among major airlines, American Airlines has the lowest score of 1.75 (Grade D).
- Nearly all regional airlines have poor Water Safety Scores. Mesa Airlines has the lowest score among rated regional carriers at 1.35 (Grade F), and CommuteAir is second-lowest at 1.60 (Grade D). CommuteAir shows an alarming 33.33% total coliform positive rate.
- The study window analyzed 35,674 total sample locations tested for total coliform bacteria across all airlines. Of these, 949 locations (2.66%) tested positive for total coliform.
- Maximum Contaminant Level violations for E. coli were identified as the strongest downward driver of airline scores. There were 32 such violations across the 21-airline universe during the study window.
Unhealthy water violates the U.S. 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. However, the study also found that 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.
Airline Water Safety Scores
(5.00 = highest rating, 0.00 = lowest)
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)
In Canada
In Canada, the federal government advises that air operators have regulated responsibilities through the Canada Labour Code and Department of Health Act to both their employees and passengers to ensure that the potable water provided on board aircraft meets the Public Health Agency of Canada’s Potable Water on Board Trains, Vessels, Aircraft and Buses Regulations.
Air operators that that transport 25 passengers or more within Canada are required to provide water for drinking and personal hygiene; preparation of food; and ice for refrigeration or for beverages.
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