Which U.S. Airlines Have the Dirtiest Water?

When United stopped serving Starbucks coffee on board in favor of truly terrible Fresh Brew, Delta picked up a Starbucks deal. As an early signal that the airline was trying to turn itself around under new leadership, United started serving Illy coffee (and Stroopwafels).

There’s no doubt United uses the best coffee of any U.S. airline. However inflight coffee poses two challenges: the pressurized cabin and the water used for brewing.

The New York City Food Policy Center at Hunter College studied airline tank water and found it severely lacking – and not just for coffee, but in some cases human consumption.

They tested for coliform bacteria as well as E. coli. They looked at the number of violations at each airline of the EPA’s s Aircraft Drinking Water Rule. And they looked at how cooperative each carrier was in their testing. And they ranked each airline with a score of 0 to 5.

American Airlines regional subsidiary Piedmont had the best water in the ranking, while Republic – which flies regional jets for American, Delta, and United – scored worst.

Airline  Score 
Piedmont Airlines          4.33
Alaska Airlines          3.30
Allegiant Air          3.30
Hawaiian Airlines          3.10
Sun Country Airlines          2.78
Frontier Airlines          2.60
Southwest Airlines          2.40
Envoy Air          2.11
GoJet Airlines          2.00
Trans States Airlines          1.78
Delta Air Lines          1.60
American Airlines          1.50
Compass Airlines          1.22
PSA Airlines          1.22
United Airlines          1.20
SkyWest Airlines          1.11
JetBlue          1.00
Spirit Airlines          1.00
Endeavor Air          0.78
Air Wisconsin Airlines          0.68
ExpressJet Airlines          0.56
Republic Airways          0.44

Airlines refill their water tanks at a variety of destinations and their supply chain involves “the equipment used to transfer the water, such as water cabinets, trucks, carts and hoses” which varies markedly.

The study authors recommend not drinking any way water that didn’t come from a bottle, not drinking on board coffee or tea, and not even using water from the lavatory to wash your hands. I wouldn’t go so far as this last step and hope you wash your hands after using the lavatory, though I fully endorse using a paper towel to open and close the lavatory door.

Coffee Grounds are Useful for Eliminating Lavatory Odor

It Works Even Better When the Grounds are Out of the Package

By the way airlines should clean their planes more often, too.

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community InsideFlyer.com, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

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  1. I was recently given a bottle of water to wash my hands with in AA domestic first because the sink was broken. Guess that was an upgrade!

  2. Not washing hands? That’s ridiculous. Just use plenty of soap and lather up and use paper towel to open door.

  3. If the airline boils the water before serving then will remove bacteria. At altitude though boiling temp is lower, of course. Has anyone very been made sick? I am more worried about chemical pollutants from old pipes.

  4. Airlines don’t care about standards until they are forced to comply.
    Clean drinking water is a simple standard that needs to be enforced.

  5. Why don’t airlines just use bottled water to make the coffee? It weighs the same as tank water, and the cost can’t make that much of a difference.

  6. I’m sure it’s easier for a small carrier like Allegiant to have clean water systemwide than a big one like Delta. Nevertheless, I would never drink any water from the tank.
    They should use bottled water for coffee – given how little water is needed for coffee anyway, this seems sensible!

  7. You should check the tab water in your home, then get back to me, you might prefer what’s on the plane.

  8. Bunch of germaphobes (already knew Gary was one). Have drank water (and coffee) on many airlines around the world over last 35 years as well as local water (with few exceptions). Also don’t use towel to open bathroom door paranoid about germs. Never had a problem. I’m a believer you build up tolerance so best start early and deal w the real world instead of trying to avoid it.

  9. Look at the Big 3 + Southwest

    Airline / Total Score / Avg # Violations Per Aircraft / E.Coli Positives / Coliform Positives

    WN / 2.4 / 0.04 / 2 / 122
    DL / 1.6 / 0.23 / 15 / 359
    AA / 1.5 / 0.11 / 23 / 660
    UA / 1.2 / 0.10 / 3 / 205

    UA looks much closer to WN on it’s stats than DL or AA but scores lower than all? Their methodology just has the junk variable “Helpfulness” and they use that to fudge certain airlines up or down in their rankings as necessary.

    I was already going to completely dismiss anything they say because they tell you NOT TO WASH YOUR HANDS in the bathroom (hand sanitizer is not soap, sorry people) but this just proves it further.

    I’m still Team DrinkTheCoffee and I haven’t gotten violently ill yet. Move along people…nothing to see here.

  10. I’ve flown many overseas international flights on UA and most of the time I forget to bring my water bottle to rinse my mouth after I brush my teeth and use the water in the lav to rinse my mouth. So far I haven’t gotten sick yet.

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