Landlord policy claim denied for home previously being unoccupied

[Scott S.]

I have a SFR in Southern California, the past tenants moved out about six months ago, and due to some repairs/upgrades and market conditions did not find a new tenant until recently. During this time period both myself and the property manager were at the house regularly, did not notice any water issues. Before the new tenants moved in, we made sure everything was in working order and the house was thoroughly cleaned, still no issues.

Tenants move in and shortly thereafter water appears coming through the floors damaging floor boards, cupboards, etc.  Immediately call plumber, turns out water damage due to slab leak, had the entire home was re-piped, and  submitted a claim to insurance for the damage the water caused to the house.

To my surprise, the claim was denied because the house was not "occupied" for thirty days prior to the date of loss.  I had no idea there was no coverage at all while the property was unoccupied, and even with a new tenant it seems there would not be coverage until they occupied it for at least thirty days.

So I am curious how other landlords handle this, do you just roll the dice in between tenants?  Do you have someone "occupy" the house once a month to keep the coverage in place, maybe a house-sitter or go stay there yourself?  If so, how do you prove that it was occupied once every 30 days?  I see now there might be separate vacancy coverage or specific endorsements available, but seems that might be expensive given theft and vandalism concerns.  

I welcome any thoughts on this, the insurance piece of being an owner and landlord is increasingly frustrating and time consuming, especially in California, to the point I wonder if it is even worth having insurance, as my experience with insurance companies continues to be that every claim is either denied outright or does not fully compensate for a loss.  

Appreciate any insight!