A 2026 airline water safety study shows that almost 3% of the water tested in circulation with operators in the United States is positive for coliform bacteria. There was a varying level of contamination observed with different carriers, which revealed that American Airlines and JetBlue are the highest risk.

The study found that almost all airlines still failed to meet the federally mandated Aircraft Drinking Water Rule (ADWR), in place since 2011. Researchers conducting the study concluded that travelers should not drink any water on an airplane unless it is coming from a sealed bottle.

Risky Water Supply Onboard

The federal government primarily created regulations to prevent E. coli contamination. The primary measure is that airlines must disinfect and flush each aircraft’s water system at regular intervals throughout the year. Because planes regularly refill their water supplies from many different locations around the world, the systems in the aircraft and on the ground are both potential breeding grounds for waterborne disease.

After testing positive, airlines are required to quickly retest, disinfect, and either shut down or flush the affected systems. The exact guidance depends on the measurements of the results, and the Environmental Protection Agency (EPA) is one of the governing bodies in charge of managing the process.

Not only did the study determine that flyers should not drink the water that comes directly from the system aboard commercial aircraft, but that washing hands using the sink water is also not recommended. Instead, researchers recommend using alcohol-based hand sanitizer at least 60% concentration level. Director Charles Platkin of the Center for Food as Medicine & Longevity made this statement, according to HealthDay:

« Delta Air Lines and Frontier Airlines win the top spots with the safest water in the sky, and Alaska Airlines finishes No. 3. (…) Nearly all regional Airlines need to improve their onboard water safety, with the exception of GoJet Airlines.”

The Best And Worst

The way that the study assigned scoring to the airlines combined five weighted factors that provide an assessment of the overall water quality used by each carrier. The criteria include violations that have been previously given to aircraft, the maximum contaminant level violation for E. coli, and rates of coliform positive tests.

Researchers also factored in public notices given for previous water safety discrepancies and considered how often the airlines’ water systems are disinfected and flushed. Under the system established by the study, any score over 3.5 would be considered safe water, earning a Grade A or B level.

The Institute determined that the EPA was not enforcing effective oversight to ensure that safety standards are maintained on a regular basis. They report granted a “shame on you” award to the EPA for its part in the results.

What Should Flyers Do?

The primary action that passengers can take to avoid any health risk from the poor water quality on board is to avoid drinking coffee and tea on the flight. When drinking water, only consume water that you have brought from a clean water source or the sealed bottles provided by in-flight meal service.

As previously mentioned, washing your hands using soap and water in the sink is not recommended. Hand sanitizer is more effective, as the contaminated water may actually do more harm than good. Brushing your teeth is also not recommended, as you may ingest the contaminated tank water in the process.