And gotta love when the remediation bill is $1k+ on their $750 deposit and they still want to argue over a $15 charge.

All states have the same inside protection, however the outside protection varies greatly.If some of properties are in states that do not offer good outside protection (ie charging order not being the sole remedy), you will then create a holding LLC in a state that has this great outside protection; This LLC will then own all the sub LLCs.Another aspect also is that some states offer anonymity adding another layer of protection.

Some will cover the mold remediation, IF it is a covered loss. 

@Francisco D Contreras Do you have anything in your lease pertaining to nuisance complaints or remedies on loud noise?

Refer tenant to the water company for a remedy. 

@Ethan SpielvogelAs a general rule, you would want an LLC in the state where the property is located to be able to make any legal action in court (eviction for instance).However as some states have week asset protection statute (the charging order is not the sole remedy), you would then need to have this local LLC owned by another LLC in a strong state like WY.Now because you are located in CA, you are subject to the CA regulation that will force you to pay an expensive local franchise tax on your out of state LLC.

Assuming your lease requires this, you send her a letter of default with X days to remedy. 

For my own piece of mind and that of my contractors, I would have an asbestos evaluation done if the rehab was likely to disturb any, IE tearing up floor tiles, siding or shingles, but I'd be weary of hiring anyone that also does asbestos remediation as they are likely to overstate/upsell. 

@Dave Vona the best thing to do is get an inspection/remediation company to give you an estimate so you know exactly what it will cost.

And it is a very common remedy in real estate.