Diggy diggy thread I know, but better than creating a duplicate.
First post in the forums, and I thought of this idea, together with a 'necesity' system. Dwarves get loaded with a 'poop' internal value after eating, and 'pee' after drinking. When those values go over a certain value, dwarves will get a 'hurry' status, and they try to get to a bathroom, public or private. Those who don't find one must go outside near a tree and do stuff, with a minor(?) unhappy thought. If still unable to find a spot, they poop/pee on their underwear and get a strong unhappy thought, along with cloth getting one level of wear. Additionally, if they want to poop, after the 'must find a tree' stage they get a random chance of generating miasma at their tile. Yeah, those purple clouds of FUN.
Toilets must be connected to a dump zone, like the caverns or even magma. Both poop and pee are considered liquids, which leave potash after evaporizing, like how water covers tiles with mud. Said potash can be collected for use in fertilization, saving ash use to soapmaking.
This is a humorous topic as one might see, if this section is too inadequate for that, I don't mind if it's moved.
Goodbye.