http://www.bbc.com/news/world-us-canada-32196177"Nasa scientists have projected that reservoirs could run dry within a year"http://www.zerohedge.com/news/2015-03-16/californi...Is (So) Califoria 'turning back' into the desert, and if so how will this affect our investments in the state/region... economic collapse?

Managing/overseeing a roof collapse is not typical wear and tear or tenant-related maintenance, and it would never be the PMs job to manage such a repair, or even get quotes without a separate agreement.  

A turbulent time during the housing market collapse.

Am I looking at any liabililty if someone is say " horsing around on the furniture" and it collapses on them??

I had a popcorn ceiling in a bathroom collapse because the fan went bad and the tenant didn't report it.

People don't get multi-million dollar awards because of no-fault accidents.So, limit your liability by removing problems you could get sued for - make sure the electrical is to code, and there are fire extinguishers, provide outside lighting if it's a bad neighborhood, take care of pest control, make sure the roof won't collapse, that stairs are in good order, that there are no swimming pools kids can get into.I just can't think of any "terrible injury" that could have been caused by you, if you just take care of the property.And, of course, get a reasonable amount of insurance to cover you for any accidents that may happen, that a tenant may file a claim against you for.But, to put things into perspective - I managed 25 units for 8 years as a resident manager.  

(2) Landlord will NOT pay to repair the following items unless caused by Landlord’s negligence: (a) conditions caused by Tenant, an Occupant, or any guest or invitee of Tenant; (b) damage to doors, windows, and screens; (c) damage from windows or doors left open; (d) damage from wastewater stoppages caused by foreign or improper objects in lines that exclusively serve the Property;I assume the toilet was working fine when the tenants moved in and at the stoppage is just located in the toilet, then this is something that was caused by the tenant or a guest and at the tenants responsibility.The only time we would charge an owner for clog is if the sewer line is collapsed and is usually evident by roots or mud in the line.If the sewer line is fine and any clogs are deemed the tenants responsibility.

Around that age, things start collapsing or shifting and that could be a 20-30K repair which, in my opinion, doesn't add much value.Otherwise, it seems like a good deal.  

Other "what ifs" are a local economic collapse, natural disaster that wipes out many of your properties at once, etc.

Market Dynamics: The current oversupply of (STRs) in some markets is better understood as a market correction rather than a sign of impending collapse.