Earlier quoted context omitted.
If you're worried about that amount of water, what do you do when it rains?
Some idiot figuring out that nice hole in cladding is right place to direct it... Or people under balconies when it is not raining not wanting to have water drop on them... In many cases balconies have less than ideal designs.
Best would probably be to use the existing rainwater pipes that lead down to the sewers - all building have those. But good luck getting that past your HOA-equivalent, as that will most probably involve some modifications to the building and we can't have that, no!