While we don’t have any stats for the Canadian airlines, the quality of the onboard water on major U.S. airlines varies significantly, with some carriers potentially violating the EPA’s Aircraft Drinking Water Rule.

The study analyzed data from 10 major and 11 regional carriers, with four major airlines earning A or B grades and most regional airlines receiving a D grade.

E. coli contaminant level violations were a significant factor in the airlines’ scores, with 32 violations observed across all airlines during the study period.

Delta Airlines had the highest overall score and emphasized its commitment to providing clean drinking water, while other airlines at the bottom of the rankings defended their practices.

The EPA has issued compliance orders to airlines in violation, but has not levied many civil penalties.