There are codes that allow for more density or at min ADUs on SFH lots now.

Your first challenge is - you shouldn't buy based upon zip code!

From tax stand point I would think you can separate from primary and be okay with IRS being that IRS will not be local code enforcement.  

There are some zip codes where you can indeed get above market rent with S8 (even after deducting utility allowance), but some where they are lower.

It stops nonsense before it starts and keeps your property safe (and your sanity intact).Hard on Paper, Soft in PracticeMy lease was stricter than a middle-school dress code: no overnight guests, no smoking anywhere, and quiet hours that would make a library blush.

Hi Jeanette,What zip code is your current duplex in? 

Partner with a Real Estate Tax SpecialistThe tax code is complex, and mistakes can be costly.

They might have insights on specific zip codes or pitfalls to avoid. https://www.biggerpockets.com/forums/521

When under contract at 300k with the expectation that codes would be the determining factor on what can be done on with the property, as it relates to new construction.

Would definitely check local zoning / code enforcement laws as well.