No one should be putting paint, oil, etc down any sewer system.....Get it cleaned regularly and you'll be fine....Of course make sure that it is a well functioning tank, leach field to begin with.

I'm not planning on doing any crazy expensive upgrades, more so functionality upgrades.

Everything functions great and the home is a great addition to the portfolio Lessons learned?

There are not updates on DSCR or checking in on reserves after closing, etc... these loans work just like a conventional for functioning purposes minus being reported on your personal credit and they normally come with a Pre-Payment Penalty (which is minimal with a pro lender).You do save some money on blanket loans... but... not really that much. 

I'd like to simply tell the current tenants they're not functional and that they're not allowed to use them.

I have clients that have bought in higher priced markets but they buy fully functioning and licensed properties I think that mitigates the risk a ton.. it seems like the areas that have no license requirements are the ones you have to worry about.although depending  on how much income you would get but you could have a 7 day minimum that only costs 3 nights.. 

If you need that much security, you may want to consider investing in a different market.There are plenty of security cameras with night vision, so a simple motion-detector light would be a more functional option (spooks intruders and lights the path for occupants).

Although this is a single family home, I rent it by the room to college students at the local university who want a communal living space, functioning similarly to a frat house.

@Nicholas Preston try searching the Secretary of State website for whichever particular state you are looking in and use the Search Businesses function on the website.

Granted, there is a sort by time function, but even if a deal can be posted within last hour, based on our current market, it could still be snatched away.