Legal Question in Real Estate Law in California

Just call your renter's insurance carrier and they will take care of everything. If you decided to go without renter's insurance, thereby wagering maybe $150 that you wouldn't suffer a loss, this turned out to be an bad bet on your part; and yes, you will have to pay your own expenses and sue the tenant of the apartment above you, and who knows, maybe they had renter's insurance. If indeed they did have insurance, you will have to hire your own lawyer, at your own expense, to get any of your expenses paid.

I've looked at several legal references to try to find an answer to the question you asked, i.e., whether the landlord needs to pay your expenses in advance rather than reimburse you. I did not find anything exactly on point. However, keeping in mind that this is a kind of repair that the landlord is required to make, if the occupants need to be out of the apartment one or two or even more nights, the landlord may insist on that without committing a breach; and I think the landlord's liability to the tenant would be limited to an abatement of rent for the period the tenant is dispossessed. A motel and restaurant meals would be more money unless the apartment is very expensive. I'd take the deal and get the apartment back in a safe condition ASAP. By the way, are you sure the leaking water contains asbestos? How do you know?