Have you ever noticed that some flight attendants never drink hot water during a flight? You might think this is because they're on duty, and when they take their break, they are in the back somewhere in their flight attendant cubby-holes quaffing cup after cup of coffee. But according to one flight attendant, this really isn't the case. “Flight attendants will not drink hot water on the plane," a flight attendant told Business Insider. "They will not drink plain coffee, and they will not drink plain tea.” So why not? The answer, which comes from the EPA, is pretty disgusting. The water used for hot drinks on flights comes straight from the tap rather than from bottles. The EPA did a study on the water back in 2004 and found that 12.6 percent of the samples contained coliform. Not grossed out yet? Coliform count is an indicator of how much fecal matter there is, thus determining the sanitary quality of foods and water. "Both total coliform and E.coli are indicators that other disease-causing organisms (pathogens) may be present in the water and could potentially affect public health," the study noted. To make things worse, the EPA also found that of the 158 planes they looked at, two of the planes tested positive for E.coli, which can cause diarrhea and stomach cramps. Business Insider reports that one in eight planes fail to make their standards for water safety, which is why some flight attendants say they won't touch the stuff. In response to these studies, the EPA changed their standards in 2009, forcing airlines to use water sources that follow FDA guidelines. They must also disinfect their water and test their water at least once a year. Unfortunately, the new regulations may not have had the desired results yet. In 2012, the EPA ran more tests, and the results were similar. Around 12 percent still tested positive for coliform, though only 0.5 percent contained E.Coli, according to NBC 5. So how is it getting into the planes in the first place? In 2015, a study in the International Journal of Environmental Research and Public Health found that there was more bacteria in the trucks delivering the water than in the original water source. If you're thinking none of this matters because heating the water will kill off any disease, think again. “It might kill some of the organisms," environmental scientist Brenda Wiles told NBC 5. "But it’s not going to kill the majority of them,” So, if you're ordering a drink on a plane, maybe just stick to orange juice.