I thought the topic of this thread sounded familiar and, sure enough, we had a very similar thread in 2011.
Here is my response from that thread. My answer has not changed.
ETA: For those who do not want to click on the links, my answer is I have never urinated in the shower.
But really, I have heard that. Is it true?
When I was younger, I thought nothing of peeing in the bathtub (while I was actually in it!) Today, I wouldn’t do that… But to be honest, I don’t think there’s any valid reason to avoid it. My own sweat is more highly concentrated with toxins, and urine is, if not absolutely sterile, pretty damn low on the scale of infectious materials. As I noted above, it’s so close to non-toxic, some people drink it.
The morning pee is usually so urgent that I can’t wait for shower time. I have to go NOW!
Although, I have nothing against peeing in the shower. It’s the place where dirty things go to get clean. It doesn’t bother me that poop particles from my butt crack are in the water washing down to the drain, or that dirt under my fingernails and in my belly button and earwax and toe jam all end up washing down the drain. Pee is significantly less gross than lots of stuff that everyone takes into the shower with them.
During the last presidential election some pundit described Mitt Romney as “the kind of guy who would get out of the shower to take a piss.” I’m definitely not a Mitt Romney kind of guy.