It is not just multi-family, as multi-family usually have multiple complete units that are separate; you have only a single unit.WHEW am I glad the nanny state is not (yet) universal!

If there is a real need, add surveillance cameras.  

Obviously you can camera the HVAC lines if you want to look at for mold/water.

Running a camera through the sewer lines will let you know their condition. 

Judges are very familiar with tenants tactics.You will now need to send a pay or quit notice if you do not receive the next rent payment in the new amount and follow that up with a non renew of their M2M lease.Unfortunately being in nanny state CA you may not have these options.

I live in a Smaller town, and I use my phone camera and Google Keep.

If you’re worried about damage you could also add camera security systems to units being shown.

http://www.walmart.com/ip/Inspection-Camera-WIC-1229G/39097776Whistler WIC-1229G Diagnostic Inspection Camera $393.3' flexible camera tube9mm wide angle lens2.4" LCD monitorImage rotationWater-, alcohol-, gas-, diesel- and oil-proof cameraMight be a useful tool for some of you DIYers out there.

They attach a GO PRO camera to the bottom and if they crash land the camera is done and you made no money on the job.I was thinking he said it was about 300 minimum and can go higher in price.

All of those attempts are on their camera - me trying to open a locked door the first two times.