The lavatory in my medbay appears to be destroying water. Clean water is fed into it, but none comes out after dupes use it. I don't know if dupes are even supposed to be using this lavatory, as it's assigned to the medbay and they're not sick, but they are using it and polluted water isn't being generated.
The medbay is 8 tiles wide by 4 tall. The lavatory is on the right wall and is fed from the bottom. It's made from copper and fed with sandstone pipes. The output pipe goes upward.