I'm sure the idea of having a hot tub, even a small inflatable soft tub, on your balcony would be easily refused by your property manager and condo board. There is too much liability and issues associated with it -- structural concerns, sound and vibrations from the pump, how to properly fill and drain it, what happens if the tub leaked or burst, insurance roles/responsibilities, etc.
I would hate you if I was your neighbour downstairs.
If it was a terrace it would be a different story as those outdoor spaces could hold larger loads and have their own storm drain, and many terraces have their own water supply. I have seen a few units with private terraces or roof top patios that have a full sized hot tub which is a really nice thing to have, especially when you hate the thought of using common/communal hot tubs.
You typically still need permission from your property manager and board to have a hot tub on your roof or terrace.
