Who determines a rental's habitability?

[Maria T.]

Greetings all,
I joined the site quite a bit earlier to read the forums and encourage myself to invest in real estate in the future. At least, that's the plan.

In the meantime, my problem: My b/f is moving in with me and thus his house is now a rental. The house was really run down, and basically not habitable according to law, i.e. so many things not working, as my bachelor b/f worked 12 hour days for years and didn't bother on upkeep. But last month he found a family who wanted to fix the house up. When he told them it was illegal for him to rent it out in that condition they said they would fix what needed fixing as they are that anxious to move leave their apartment and move in. So he said okay.

We provided them with a list of things that need doing or repairing and it looks like they can get this all done in the next month before they move in their family. There's been no contract or anything yet of any kind and yet they've done quite a lot in the last few weeks, painted, tore out old carpeting, replaced old appliances with newer ones etc. But the question remains as to who assesses the house as "habitable" and legal to rent?

We don't have the expertise to do that, and the renters may claim all they did has made it okay for them to move in. They seem like great people, and we appreciate their doing the labor to make the house "theirs", and we gratefully intend for them to have much lower rent for the foreseeable future, but we just want to be sure that the t's are crossed and the i's are dotted before we let them actually move in to what should be a "legally habitable" house.

Thanks for any replies, and fyi we are in California.