How Disgusting Is The Water In Airplane Tanks? Do We Even Want To Know?

In the past, I’ve covered the topic of whether it’s gross to drink airplane coffee, given that it’s brewed with water from the aircraft’s tanks. One certainly wonders how clean all of those systems are. Along those lines, an interesting study has just been released, which might make you think differently about how you use water on planes… at least on some airlines.

Study ranks water safety across several airlines

The Center for Food as Medicine and Longevity has released an airline water study, which reveals that the quality of water varies significantly by airline, and claims that many airlines provide passengers with potentially unhealthy water. This is specifically in reference to aircraft tank water, which is used in the lavatories, and to brew coffee and for hot water.

Before we discuss the relative airline rankings, let me share the recommendations that are provided, in order to be “extra safe,” as it’s described:

• 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

This study ranked the quality of water provided in the tanks onboard flights, during a three year study period, from October 2022 through September 2025, and used over 35,000 samples. Each airline was given a “Water Safety Score” (ranging from 0.00 to 5.00), based on five weighted criteria.

These include violations per aircraft, maximum contaminant level violations for E. coli, indicator-positive rates, public notices, and disinfecting and flushing frequency. A score of 3.50 or better indicates that the airline has relatively safe, clean water, and earns a Grade A or B.

So, how do the major US airlines compare? According to the study, here’s how each airline was graded, ranked from best to worst:

• 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)

My take on this study about airplane tank water

I don’t think any of us expect the water in airplane tanks to be particularly clean. However, at least personally, I am a bit surprised to see such a huge variance in terms of cleanliness between airlines. I suppose some airlines really do take this a lot more seriously than others?

Another thing I find interesting is that the Environmental Protection Agency (EPA) has an Aircraft Drinking Water Rule (ADWR), which despite the name, includes rules surrounding water in airplane tanks (even though all airlines make a point of noting it’s not potable).

The study slams the EPA for not enforcing its rules, and for only rarely issuing penalties for airlines that do a poor job following regulations. That seems like fair criticism, if the difference in water quality between airlines is really that extreme.

I find this study to be interesting, but what should we actually do with this information? Should we literally just not even wash our hands on any airline? Am I supposed to sacrifice my Emirates A380 first class showers?!? 😉

Even though I’m a selective germaphobe, I put this info in the category of “interesting” and “eek,” but I’m not sure it’ll really impact my decisions going forward.

I guess my uneducated take here is that there’s a difference between an interesting study that covers best practices, vs. something we should actually actively be concerned about. Billions of airline passengers are enplaned every year. How many people suffer any sort of negative results from drinking coffee or tea or washing their hands?

Of course I’d never just drink cold water from the plane’s tanks, but it doesn’t seem to me like anything to be particularly worried about. And I suppose if that’s the case, maybe I would’ve just been better off not knowing this, since American is the airline I fly most? After all, ignorance is bliss!

Bottom line

I don’t think anyone will be surprised to learn that the water in aircraft tanks isn’t consistently of great quality. Perhaps what’s most surprising is how big the variance is — among US airlines, Delta leads the pack, while American is in last pace (which, come to think of it…).

The study recommends never drinking water directly from the plane’s tanks (which is unarguably good advice), but also suggests not having airplane coffee or tea, and not even washing your hands on airplanes. Everyone can do with this information as they please…

What do you make of this study, and does it impact your approach to using water from airplane tanks?