Even if total wastewater disposable capacity was the issue (which would be surprising considering the highly correlated toilet use in many office buildings aft

Even if total wastewater disposable capacity was the issue (which would be surprising considering the highly correlated toilet use in many office buildings after breakfast and lunch), the more fundamental problem is that the drain pipes are not distributed in a way conducive to residential use, or put another way, most people don't want communal bathrooms.