City code caps unrelated adults at three, and a four bedroom house has a room to spare
Reading the ordinance before running any numbers is the right order, and a useful case is a 4 bed 1.5 bath house, free and clear, about eleven blocks from a state university with 22,000 students, sitting in an R-1 zone. The code defines family as any number of persons related by blood or marriage, or not more than three unrelated persons, living as a single housekeeping unit. Four rooms rented to four unrelated students is off the table under that definition, though a local land use attorney is the one to confirm it, not a forum post. What that does to the numbers. Four rooms at 700 would total 2,800. Three rooms at 700 comes to 2,100, with a spare bedroom left over. A whole house lease to a family in that kind of neighborhood runs 1,850 to 1,950. So three rooms still beats the whole house lease by roughly 200 a month before utilities of about 300 and internet of 70, which erases the margin. The fourth room was the entire spread. Options worth weighing: rent to three and use the fourth room as a shared study, which helps the pitch but doesn't pay; pursue a special use permit or rooming house license where the city offers one; or take the whole house lease and stop trying to be clever about the zoning. A useful question before any of that is what actually triggers enforcement in a given jurisdiction, complaint-driven versus proactive, since that shapes how much risk the first two options really carry. Special use permits for this kind of thing do get granted in some jurisdictions, but the process and the odds vary enough by city that it's worth a call to planning staff before betting the underwriting on it.