You will need to gather assumptions or facts on property management fees (10% typical average), vacancy rate, down payment or skin in the game (typically 20% for conventional bank mortgages or 25% hard money lenders), purchase costs ( could be more or less than asking price), rehab costs/expenses( estimated costs of repairs in your area on common repairs/ fix up costs to make Rental habitability, security, safety within or above state and local landlord/ tenant laws/codes).

Call and ask to set an appointment to meet with any of the code inspectors of rental properties in the city you are looking at.

I'm surprised that there isn't a site that you can just put in the zip code and get in seconds. 

Hi there, before we buy another investment closer to home I would like to look at the Houston market and was wondering if anyone could give me a few zip codes to focus on.  

I've studied tax code and see some definite advantages in holding and utilizing BRRR.

Missed steps and missteps could result in violations and costly fines not to mention the cost of doing it over to meet codes.

I randomly plugged in a Bay Area zip code and $500k loan amount, from a random PMI company that I haven't shopped, and this came back:Break even on single premium PMI is $9200 / $170 / 12 = 4.5 years. 

They said we can do a pressure test but our inspector can't do it because it's against code for him to do it.

A Go-and-Show means they give you the code but there isn't anyone to coordinate with.

This is one of the questions I use to think about often and have even spent TONS of hours researching trying to find that perfect zip code that was the pot of gold.