Had a camera put through the plumbing and discovered roots in the clay sewer pipe.  

A good camera system and alarm are a must.

Have had multiple camera inspections of my pipes, and they show a crack in the cast iron pipe which caused the backup.

"Put camera in sewer Sewer pipe is aprox. 85 feet long and the first 75 feet of the sewer isPVC, which indicates that the sewer has been replaced up to 75 feet.There is a belly at 20 feet where pipe goes down then back upAt 75 feet the pipe is shifted (most like due to improper bedding.).

The plumber used his snake camera, could not find a significant blockage but told me that he did see "bellies" which would be around a $20K repair and would consist of extensive plumbing work around the house.

They aren't that secure (anyone with a crowbar could access a locked one), so I think next time I'll stick an outdoor web camera facing them. 

I would like to add some cameras that we can access buy phone remotely.

I've also installed cameras around the property but that's done little to remedy the situation. 

I don’t want tenants who hesitate to report something I should fix sooner rather than later. 4) Tenants are more likely to share photo of the issue on the spot since you just tap the camera button.

Most Security systems only maintain footage for 2 weeks due to camera memory capacity.I.