Hi Heather,
Thanks for your reply. Had forgotten that I could initiate the toilet repair by dropping a peep on the workshop. Anyway, turns out the problem went away when I exited the game to enter this forum!

Will certainly keep it in mind when the toilet breaks again. I guess the 'smelling the room' action is initiated by the 2nd bathroom's existence? Maybe a gopher got into one of the pipes in the bathroom and died in there!

Have a nice day!