This may or may not be an avenue in your market.The 70% rule is NOT a rule, it is a simple guideline for a quick back of the napkin analysis.

My back of napkin math is beginning to suggest it may not be a great investment BUT it really comes down to how much these properties rent for on average and occupancy... well, I guess and what sets one apart from another to promote return STR tenants :) We’re here now by the way.

For back of a napkin approach, I take the existing monthly income, x12 and take 40% exp ratio to get a NOI.

Ideal bird dogs are Mailmen, Delivery workers, pool cleaners, garbage men (Sorry their not a sanitary engineer unless they have a degree in engineering), and anyone else who drives through neighborhoods for a living. 

The Sanitary Inspector shall determine whetherthe said receptacles are badly broken or otherwise fail to meet therequirements of this section.C.Receptacles of refuse shall not be set out for collection, exceptduring hours of the day or days scheduled for collection of refuse, orthe evening before, and not before 8:00 p.m. of said evening.D.Receptacles shall be conveniently located on the premises for thestorage of refuse and maintained in such a manner as to prevent thecreation of a nuisance or a menace to public health.E.All refuse, garbage, combustible waste and noncombustible waste pickedup from any commercial enterprise by a private entity engaged in thebusiness of collecting and removing garbage from commercialenterprises shall be completed on the day scheduled for pickup betweenthe hours of 12:00 midnight to 7:00 a.m.

Software's cool too, but its still just a tool & a tool is only as good as the guy using it.Put in a lot of wiggle room on your numbers (conservative underwriting)Don't forget your holding costs, builders  risk insurance, taxes, utilities, security etcThis is all cocktail napkin stuff I'm giving you, you'll figure it out more.Don't overbuild but do be very detail oriented, neutral colors, VERY clean.

Go to McDonalds--bring an ink pen.Buy a small coffee--sugar and cream as you like.Grab a handful of napkins.Start sipping the coffee, and writing ideas that come to you on the napkins.Take a break.Hand write on lined paper (or put into an email) the points from the napkins, with filler sentences about each one.Maybe include a link if you think it helps.Then when you've made it financially--you can say you wrote your business plan on a napkin.Good Luck!

These rules are "back of a napkin" place to start and adjust accordingly.

Really it was used as a quick and dirty back-of-a-napkin way to screen properties, determining which were the ones to continue pursuing and which ones to rule out, not a hard-and-fast “rule”.

If you are hooked to the sewer system, they either get hung up in the pipes (you would be surprised how many SSO's [sanitary sewer overflows] are caused by flushable wipes) or get caught on the grit screens at the plant.