“Disease.”
I don’t understand that... How do you get a disease from yourself? People who sit in bathtubs don’t seem to have a problem.
If that were going to be a problem, put an UV filter in the recycle line. They use them in fish tanks to kill microbes...
Good luck with that, and legionaries disease and of dirty water being sent through the floor drain back up through your shower head, I wouldn’t do it, and I could if I wanted to.
We want the last rinse to be clean water, not the water we just bathed with.