Plane Tap Water Report Card—35,000 Tests, One Perfect Score, American And JetBlue Get D Grades

That inflight coffee and tea is made with water pulled from an aircraft tank, not a kitchen faucet. New analysis of EPA aircraft water filings graded major airlines from A to F. One carrier scored a perfect 5.00, two airlines got Ds, and the reasons are pretty specific.

A scorecard that grades 21 airlines (10 major, 11 regional) on aircraft drinking-water safety using EPA data for 3 years gave each airline a 0–5 “Water Safety Score.” It looks at:

• violations per aircraft (20%)
  
• E. coli level violations (35%)
  
• total-coliform indicator positives (20%)
  
• public notices (15%)
  
• disinfection/flush frequency (10%)

The big findings were to assign a perfect score of 5 (A grade) to Delta, and also that Frontier came close at 4.8, while American 1.75 (D) and JetBlue 1.80 (D) were at the bottom for major airlines and regional carrier Mesa, now part of Republic, failed at 1.35.

Across the dataset they count 35,674 sample locations, 2.66% total-coliform-positive, and 32 E. coli MCL violations. Regionals fare worse than major airlines with positivity rates for coliform.

This is a relative performance ranking, and not a claim about a specific plane or flight. Even on Delta I’d stick with sealed bottled beverages and be cautious about drinks made from aircraft tap water, which isn’t like the water most Americans have at home. It’s loaded into a tank, sits through temperature swings and periods of stagnation, and moves through a small plumbing network to galleys and lavatories.

There’s a dedicated regulatory regime for this: the Aircraft Drinking Water Rule. And the scorecard looked at EPA data from October 1, 2022 through September 30, 2025.

35,674 sample locations tested for total coliform, 949 (2.66%) were coliform-positive and 32 E. coli MCL violations. There were 931 total EPA rule violations.

Major airline results:

• Delta 5.00 (A)
  
• Frontier 4.80 (A)
  
• Alaska 3.85 (B)
  
• Allegiant 3.65 (B)
  
• Southwest 3.30 (C)
  
• Hawaiian 3.15 (C)
  
• United 2.70 (C)
  
• Spirit 2.05 (D)
  
• JetBlue 1.80 (D)
  
• American 1.75 (D)

American’s low score is attributed in part to public notice penalties plus E. coli violations.

According to an American Airlines spokesperson, though:

American’s potable water program is fully in compliance with the Environmental Protection Agency’s (EPA) Aircraft Drinking Water Rule (ADWR). A recent EPA audit showed there were no significant findings with our program, and we have not received any violations for any potable water cabinets or trucks that we use. Our team is closely reviewing the Center for Food as Medicine & Longevity’s analysis — including its methodology and whether it was peer reviewed — to determine any potential changes that would further enhance the safety and wellbeing of our customers and team.

This is grounded in a real regulatory dataset over a 3 year window with tens of thousands of sample locations. The study publishes its weights, penalty logic, grading cutoffs, and quintile thresholds so it’s reproducible.

Here’s one major limitation I think that’s spelled out in the methodology: the “Aircraft Sampling Operations” export includes an E. coli present/absent field, but does not include an explicit total-coliform result field.

• So the study derives total-coliform results by parsing the System Operations “Sample” event Details text, which contains two “Location:” blocks per row and includes “Total Coliform: Present/Absent”.
  
• Each “Location block” is counted as one sample location tested.
  
• So the results depend on consistent formatting.

Without looking at the raw data it’s not clear how good the coliform data actually is here, and how much that’s driving the results (though we know the percentage of score it feeds). The report also flags that many violation rows lack an end date and are excluded from totals. And ultimately this is a compliance evaluation, not a sign of current safe consumption.

My concern isn’t just about whether airlines meet minimum regulated standards. And this isn’t just an American Airlines (and JetBlue) thing. Disinfecting water tanks annually does not appeal to me. I choose not to drink the coffee, and that goes even for United’s Illy. I don’t brush my teeth on long haul flights with water from the lav sink! I bring a bottle of water in with me.

(HT: Ken A)