That's strange, I've lived here for 5+ years now, and I've never heard anyone my native spouse say anything of the sort, nor anyone else. More outrage for the outrage throne!
You missed this announcement then: “Please make sure in the shower that your mouth is not open,” Jim Craig, senior deputy and director of health protection at the Mississippi Department of Health... Specifically for Jackson, where they have been having serious water problems for a month. (This is not in the linked article, but in several others on the topic)
It's hyperbole, without the details.