Translation:The dirty toilet is in the apartment building.
" insulae, like domus, had running water and sanitation. But this kind of housing was sometimes constructed at minimal expense for speculative purposes, resulting in insulae of poor construction. They were built in timber, mud brick, and later primitive concrete, and were prone to fire and collapse … Among his many business interests, Marcus Licinius Crassus speculated in real estate and owned numerous insulae in the city. When one collapsed from poor construction, Cicero purportedly stated that Crassus was happy that he could charge higher rents for a new building than the collapsed one."
Additionally, there must exist an already existing tall buildings in order for laws to forbid buildings to exceed 25m "Beginning with Augustus (r. 30 BCE-14 CE), several emperors attempted to establish limits of 20m (25m for facade) for multi-storey buildings, but met with only limited success."[Reference: Gregory S. Aldrete: "Daily Life in the Roman City: Rome, Pompeii and Ostia", 2004] [Reference: https://issuu.com/frankvankessel/docs/the_building_brick_of_rome]
Even in Canada, an apartment (ie xxx mansion) can be just 3 to 5 stories tall.
That's meant like a figure of speech, like you'd refer to blocks in the Manhattan street grid. Every block forms a little island (~insula) confined by streets. And yes they had astonishing apartment buildings, that were densely populated and posed a considerable fire hazard to the city of Rome.