This is all so confusing, isn't it?? My understanding of Dr. Falkinham's suggestions is that drying out a showerhead is not going to kill MAC. In fact, his lab found that dessicated MAC continued to stay alive for the seven weeks of the study! Yikes. So what's a person like us supposed to do?

Dr F suggests submerging the showerhead in undiluted bleach for 30 minutes. I also have heard him say that he is fond of scrubbing, so you might want to use a brush.

With that said, I take a different approach. At home I use an inexpensive showerhead with big holes that I buy on Amazon. I have purchased both a regular showerhead and a hand-held one by AquaDance (make sure that there is a large hole setting). I swap the head out regularly and donate the showerheads to Habitat for Humanity.

When I go to my California rental property for the winter, I remove the showerhead and shower like that. I have learned to like it. I imagine I am under a Hawaiian waterfall:) Mostly, I take one minute showers. Again, not ideal, but it gets the job done. My husband uses the other bathroom and is not inconvenienced by this showerhead-less approach.