Whether you can see it or not, urine really isn't that bad. Granted it smells a bit and I sure wouldn't want to drink it, but it isn't really dirty in a disease or contagious way since it's mainly ammonia and therefore sterile.
In really scummy places, with poor sanitation, dirty bathrooms and a dirty water supply, it would probably be better to piss on your hands after using the bathroom and after washing your hands from the tap, at least that would sterilise your hands and kill most of the bugs and bacteria in the dirty water.
In really scummy places, with poor sanitation, dirty bathrooms and a dirty water supply, it would probably be better to piss on your hands after using the bathroom and after washing your hands from the tap, at least that would sterilise your hands and kill most of the bugs and bacteria in the dirty water.