Then he could AIRBNB his triplex unit since he could be potentially monitored if he is renting all of his units.

I've done some research on this the past couple of days and I've found some ideas, but I'm not sure if it's worth pursuing them or I should just give up on the idea and wait for a different property.Separate meters: From the research that I've done (a lot on BP forums), this seems to be way too expensive to consider.Submetering: This seems to be a viable option, but I have no idea how much the initial setup would cost or the how much the ongoing monitoring would cost.

It's one thing to trust your PM to screen tenants and monitor the condition of the property when the turnover is every couple of years vs on a daily or weekly basis.

Even when it's occupied, you are relying on a tenant to monitor this for you.  

I did not purchase a home warranty5. seller disclosure - Furnaces and CO monitors working and present6. seller removed CO detectors when he vacated7. cash purchaseWho eats the bill?

A property manager would be your best contact for drafting the lease and monitoring your new purchase!

If it's local, you can easily check references, meet face to face and monitor the situation. 

First American monitors several markets and has reported that the decline was widespread throughout almost all of them.

If you can't put a monitoring valve on the water supply can you put a water moisture alarms somewhere below her?  

When the AC is moved, similar to a home security system, a monitoring station will alert the owner and the police.