Good news for you is SFRs get a different treatment and do not necessarily need to be leased at the time your apply for a DSCR loan. 

Here is what I found: According to state laws (Civil Code § 1941.1 and § 1941.3), at minimum every rental must have:-effective waterproofing and weather protection of roof and exterior walls, including unbroken windows and doors-functioning plumbing, heating, and electrical facilities, including hot and cold running water and a working toilet and kitchen sink-clean and sanitary building and grounds (that is, free of debris, filth, rubbish, garbage, rodents, and vermin), with adequate trash receptacles-well-maintained floors, stairways, and railings-deadbolt locks on certain doors and windows-no lead paint hazards, and-no nuisances, a catchall provision referring to something that is dangerous to human life, detrimental to health, or morally offensive and obnoxious, such as allowing drug dealing on the premises.If I were you I would take LOTS of pictures and document everything.

I have seen old septic systems consist of an old car body for the tank and field all rolled into one (BTW cars rust away and the whole thing caves in - also provides zero treatment and discharges raw sewage to the groundwater) Proximity to a well is important.

I have done similar treatments with far less bleach and it still seems like it takes FOREVER to get the chlorine flushed out of it.  

Stay out of Coffeyville Kansas unless you can tolerate riff raff, refinery trash, drugs, thieving prostitutes, meth head squatters, petty criminals, breaking and entering, overdoses and dead bodies in your properties, tenants having adultery with other tenants spouses, walking in on intruders in your STR, 5 homicides in a year in a town of 9500, and other miscellaneous nuisances. 

All manner of sketchy drug using relatives show up and stays for weeks a time for free piggy backing of her lease.  

Neighborhood has wide streets good infrastructure but still drug laden and surrounding area really rough.

They didn't expect me to come up and give the white glove treatment and weren't happy about it!

I have pens with my info on it that I give to everyone that gets a drug screen. 

Within a mile radius we have 2 bus stops, 4 drug addiction clinics, and a mess of low income citizens in a high incarceration rate part of town.