In that era, the government did not take on the responsibility for infrastructure development. Legally speaking, they were not "rulers" but "protectors," possessing no rights over humanity, and hence no obligations—at least, that was the theory.
Therefore, this city did not have a sewer system for public use.
However, it must be clarified that the city was not entirely devoid of a sewer system.
One such system was built by the mafia.
Another was built by the protectors for their own use.
The sewers built by the protectors were entirely their own private property, unrelated to anyone else. If residents or the mafia accidentally breached these sewers, they had to properly seal them back up. Otherwise, it would be a case of "damaging someone else's private property," a violation of Dyson's principles.
Since the mafia used the sewers as secret passages, naturally, the government agencies did too.
This was one of the few tools Deborah used to avoid detection.
