Weather 
Water, water in the air, but what drop should you drink?
Buying bottled water at the airport may seem like a waste of money, but a new study suggests it might just be an investment in your health.
A new study conducted by the Center for Food as Medicine and Longevity has revealed that many airlines are providing passengers with potentially unhealthy water.
The 2026 Airline Water Study, released Dec. 29, found that the quality of drinking water on planes varies significantly by airline.
The three-year study was conducted from October 2022 through September 2025, ranking the quality of water of 10 major and 11 regional airlines.
Water was graded with a “Water Safety Score,” with 0 being the lowest score and 5 being the highest. A score of 3.5 or higher indicated relatively safe and clean water.
The study scored based on five weighted criteria: violations per aircraft, Maximum Contaminant Level violations for E. coli, indicator-positive rates, public notices, and disinfecting and flushing frequency.
In the report, Charles Platkin, director of the Center for Food as Medicine and Longevity, wrote that Delta Air Lines and Frontier Airlines boasted the “safest water in the sky,” followed by Alaska Airlines.
Delta received the highest score possible — a 5.00 — and earned a Grade A. Frontier Airlines came in second with a Grade A score of 4.80, followed by Alaska Airlines at 3.85 and a Grade B.
Among the major airlines, American Airlines had the lowest score of 1.75 (Grade D). JetBlue was second to last with a score of 1.80 (Grade D).
“Nearly all regional airlines need to improve their onboard water safety, except GoJet Airlines,” Platkin said.
GoJet Airlines was the only regional airline examined that got above a Grade C, earning a Grade B with a score of 3.85.
When traveling to different locations with a range of environmental factors, temperatures, water sources, and mechanical strains, the in-flight water quality can be affected.
Unhealthy water violates the Aircraft Drinking Water Rule (ADWR), which requires airlines to provide safe drinking water to passengers and crew.
The rule, enacted by the federal government in 2011, applies to carriers with onboard water systems that can serve passengers and crew members and operate with at least one domestic stop.
It requires airlines to take water samples from their tanks to test for coliform bacteria and possible E. coli, as well as disinfect and flush the water tank four times per year. If an airline chooses to instead disinfect and flush once a year, they have to test monthly.
Of the 35,674 total sample locations in the study, 949 locations (2.66%) tested positive for total coliform.
The study also discovered that the Environmental Protection Agency (EPA) very rarely — if ever — imposes civil penalties when airlines violate the ADWR, rewarding the agency the so-called “Shame on You” Award.
To be safe, the Center for Food as Medicine and Longevity advises travelers to never drink any in-flight water that isn’t provided in a sealed bottle, as well as not to drink coffee or tea onboard.
They also warned against washing your hands in the bathroom, saying to use alcohol-based hand sanitizer containing at least 60% alcohol instead.
Water Safety Scores — 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)
Water Safety Scores — 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)
