Is this legal/ok?

[Zac P.]

I am looking at buying a duplex that is very large and has a finished basement in each. In each basement, there is a full bathroom and bedroom. So I was thinking, this could be a 4 plex?! The basements have separate entrances behind the house. There are 3 windows in the basement living rooms, but no windows in the basement bedroom or bathroom. There is also only that one entrance in/out. Are there fire laws (restricted access) restricting this? Any other potential issues that I would run into? This could possible be a cash cow.