Published: Dec. 1, 2009

Every morning, thousands of people jump in the shower, but many don’t realize the irony of this practice.

Several different types of disease-causing pathogens lurk inside common showerheads, according to a CU-Boulder study led by distinguished professor Norman Pace of molecular, cellular and developmental biology. One in particular, Mycobacterium avium, has been linked to pulmonary disease. It usually affects people with weak immune systems but occasionally affects healthy people.

“If you are getting a face full of water when you first turn your shower on, that means you are probably getting a particularly high load of Mycobacterium avium, which may not be too healthy,” Pace says.

While pathogen levels were much lower in showerheads from smaller towns that primarily rely on well water, researchers detected much higher levels in metropolitan areas like Chicago, New York and Denver.

So, is it safe to shower? Pace says it probably is as long as a person’s immune system is not compromised. He says plastic showerheads are more likely to load up on disease-causing bacteria, so metal ones are a safer option. People can protect themselves by changing showerheads regularly.