The Vampire Corps actually worked on a shift basis. There would be those that lived on the barracks closer to the wall and lived on-site—protecting the place from any incoming dangers, like the beast wave they had faced earlier in the day.
Then, there would be those who were allowed to live in the city nearby. They would just have to come to work in the daytime. Essentially, every member of the vampire Corps unit had two living quarters.
One temporary when staying at the barracks and the other in the city, a permanent home for them and their family. Of course, there were also other humans and vampires in the city who weren't part of the Corps; they just generally lived there as citizens would.