I have received and collected all pictures and complaints about this roommate.The icing on the cake was when she had a loud argument with another roommate which was recorded on a surveillance camera. 

If I were you, i'd get a second opinion and have a plumber snake out the main line then scope it with a camera to confirm whether or not you have a bigger problem.

Nothing prevents you from installing exterior cameras or other security to make sure tenant is obeying your lease.

I’m honestly not sure why anyone would pay someone stateside to handle property management when it is so cheap to hire someone offshore to do a high-quality job.My offshore PM can set door codes, message (or call) guests, schedule cleaners, adjust the thermostat, monitor my cameras, & call a plumber just as easily as a local PM can, for 1% of the cost.

I put security cameras up around the property to protect against theft but I still get the random car stops in my driveway for 20 min here or there.

Security cameras, signs in the yard, sit and wait for the people and take pics for evidences, ...

Put a camera on the front of the house that looks at the parking and trash area only, those are the other two most common complaints.  

Internet (you may need to have this if laundry machines, security cameras, etc etc need to be accessed remotely; with a big enough property companies may pay you to be exclusive - larger apartment complexes, MHPs, RVPs and marinas) Payroll, Payroll taxes, Employee benefits & workers' comp insurance (if onsite employees)Vehicle expenses, repairs, licenses, gas & oil & insurance (even for cushman carts for maintenance people)Licenses Bank charges (NSF checks etc; I include an allowance for this in expenses just in case; also credit/debit card fees if tenants pay with cards) That's all I noticed. 

They caught one of the subs doing drugs and not even working for the entire day in a camera.

I have security cameras, wifi thermostats, wifi water heater and I just use a standard lockbox.