Who monitors and enforces this?

Water is big difference... that utility is usually paid by landlord , cost to sub meter is very expensive and you'll learn to monitor your bills.. you'll tell if extra person moves in or if you've go a leaky toilet. but good idea is to check meter when no one is around and see if the spinner is still, if no you've got a drip, or leaky toilet, so put up notices and inspect.

Amazon, Microsoft, Boeing plus many other major companies are creating so much growth, I would love to monitor locations this year).

My elicited experience tells me to keep things at status quo for now and monitor the rental market.I look forward to any updates you provide.

I told him face-to-face in no uncertain terms to stay off my property and I was prepared to involve authorities if necessary.As @Marcia Maynard says you will need to be very diligent about monitoring the state of the property.

It has two...an oil monitor (with new filters) and the wood stove (common in the area) She refuses to use the wood stove and says she cant afford to buy oil.I served a 30 day notice which was she claims is invalid as it wasnt signed by me...but for me. 

Regular inspections to change HVAC filters, etc can take place to monitor the residence but just the advance rent alone wouldn't scare me off.

Yes, I decided to add a Defiant biometric lock to the basement where the laundry is and installed a security camera to monitor the room. 

If you do have mold where she is staying make sure you have completely remove the mold and monitor it.

Companies like SimpliSafe have deals going on frequently for various packages, subscriptions are economical for 24 hour monitoring.