As the study explains, 11 major airlines and 12 regional airlines were investigated and were scored on a scale of zero to five. A score of three or higher indicates the water on board is safe. Ratings were based on different criteria, including the presence of coliform or E. coli, fleet size, and how many times they violated the government’s ADWR (Aircraft Drinking Water Rule).
After the study was done, only three out of 11 major airlines received a three or higher – Alaskan Airlines, Allegiant, and Hawaiian Airlines. For regional, Piedmont Airlines received the best score with 4.33.
The airlines with the lowest scores were Spirit and JetBlue. They both received a 1 out of 5. For regional, Republic Airways received a 0.44.
The study says for a passenger to protect themselves, they shouldn’t drink water unless the bottles are sealed. This also goes for the water served in coffee or tea. They also add that passengers should use hand sanitizer instead of washing hands in aircraft bathrooms.