Call you local zoning or code enforcement office to find out for sure.

High level market research has been completed and I have narrowed to about 20 zip codes in my area, which is still a lot... 

then what zip code ?

@Spencer Herrick like most of the folks said here, it's about your team and being sure you have a solid due diligence process in place...no need to see a property in person if the property meets all the criteria on your due diligence checklist...the first 35 checklist items are crossed off in the first 3-days of due diligence...One thing you have to remember is almost every existing and new structure in the country was built by a professional developer that met strict requirements set by building codes...properties can have issues, but almost anything can be fixed...overall SFR and MF homes are incredibly durable.

I don’t know a your specific codes but if wetlands are present on the property, there are setbacks and other rules to follow which could make some lots lose their value.

I somewhat agree with and earlier post.Mild enforcement and have all comply with code regulations and licensing.That is a fair game and we all need rules to be able to play.Best C

Is the city doing one area at a time and making sure everything is up to code proactively? 

If it is one lot/parcel and zoned for two units, meets health and safety codes should be good.  

This should be in the written report.....some guys color-code the problem items.

@Nicolas Whitman the cash buyer list from Propstream has been pretty good for me; I can give some cheat codes when it comes to working that list.