One time it was caused by a water pipe leak in a wall cavity that went undetected.

@Brian Pulaski Wholesalers get property under contract in "as is" condition...And again, sellers are 100% aware the wholesaler is going to make some kind of profit......Just as a seller could put a property on CL to get more, China manufactures probably could get more for the Iphones that Apple pay them to make, it's called wholesale for a reason....

I have a beach rental in southeast North Carolina that had a plumbing leak inside. 

Pipes were leaking from every where.  

For example, Landlord is responsible for a leaking toilet while Tenant is responsible for the clogged toilet since it was Tenant's use of the toilet that caused the clog.

I'm a newbie and went to see my first motivated seller property last night and took a bunch of photos on my iPhone.

I use various water sensors with Hubitat under sinks, behind the frig and at the water heater to notify me of any leaks.

PAR leases (pennyslvania realtors association leases) say  "24 hour notice when possible" however, that is not a right to just come and go when the landlord wants. if you had a bad leak or an emergency repair and he/she couldn't get a hold of you then by all means, enter the property to fix it, but it sounds to me like harassment and an invasion of privacy. no good!

remember that even if you are ok with losing a bit of money very month, all it takes is a broken AC or big water leak for you to lose a lot more.  

Luckily my 2 homes there have minimal damage- just a roof leak.