For anyone wondering how this is possible: by violating fire code. He says he, then he and his wife, then one or both of their children were sleeping in the closet. I'm not familiar with the language of the California Building Code, but in the 2014 verison, volume 1, chapter 10 gets into the limits. The closet is not a "sleeping unit": it doesn't meet the 120 sqft minimum, doesn't have a wide enough door, and doesn't have two methods of egress. There's probably more I didn't find.

I know this seems like tedious legal nitpicking and the main apartment room is right there and "everybody does it", but nearly every line of fire and building code exists because of a preventable tragedy. Even if it's not against the lease it's unsafe. (And he built a barely-braced lofted bed in an earthquake zone!?)

The author happily compounded the rent they saved every month but failed to compound the increased risks they took every night.