That's because wherever there are public tours, and most especially crowds of children, there are public drinking fountains and they are always busy.
9NEWS wanted to find out if they are they clean, and we enlisted the help of an expert.
Metro State Professor of Biology Dr. Rebecca Ferrell supervised our project. The drinking fountains she tested were "swabbed" with sterile sticks, and then that result was applied to a plate for culturing.
We tested three big public venues: The State Capitol, with all of its tours; Denver's main public library, just across the street from the Capitol, with its large cross-section of local residents; and Denver's big public bus terminal, with its crowds of travelers from across the country.
We wanted to find out if there were any organisms in water fountains that might be able to grow in humans.
"There are lots of environmental organisms that look pretty disgusting, but actually aren't going to harm anybody," Ferrell said.
Those that can cause harm will grow at 37 degrees Centigrade, or 98.6 degrees Fahrenheit. That, of course, is body temperature.
"That's why I incubated them at that temperature," Ferrell said. "I was only interested in things that might be able to grow in a person."
The bus station had the worst looking cultures. Orange colony's of bacteria with the potential to be human pathogens. They're not a huge threat to extremely healthy individuals, but Ferrell says there are those at risk.
"Someone who's being treated with immuno-suppressive therapy, for whatever reason, maybe for arthritis or something like that. Or someone who is HIV positive, this could be very bad news for them," Ferrell explained.
In the library, we checked the water fountains on the children's floor and the first floor. Again, we found more bacteria on equipment that was just not getting cleaned.
"What we know is that they're not getting rid of it from day to day and it's growing up to high levels," Ferrell said.
The cleanest fountains in our survey were at the State Capitol. For all of their use, they sparkled. There were virtually no bacteria at all.
A dirty water fountain may not faze you, but if it does, the next time you absolutely must drink from one, we offer this advice from our expert: "The take-home message of this really is let the water run for a couple of seconds, before you drink from it, and you're going to wash out any loose bacteria that might be down in the nozzle. And then, don't put your mouth on the parts of the fountain," Ferrell said.
The Denver City and County Building also gets high marks for their drinking fountains, which were also very clean.
One last tip: If you're helping your child get a drink at a water fountain, make sure they can get up high enough that they can get into the stream of water, and they're not putting their hands in the basin and trying to climb up. If they do that, then take them and wash their hands. The basin is usually full of bacteria because they are wet most of the day.
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