"Real" lot minimums for a lot to be buildable in Memphis?

[Sylvia Castellanos]

This is directed at people in the Memphis, TN, area.  

I am considering buying two or three lots inside Memphis that are about 0.17 acre. I looked up the lot minimums for Shelby County, and these seem to be 15,000 square feet with a 100 foot width. I don’t know if Memphis has its own minimums that override those of the county. These lots I am looking at are about 7,500 square feet and about 50’ in width. Now here is the thing. In recently decades municipalities have passed lot minimums that render a huge number of the existing lots unbuildable, so they have had to accept grandfathering in a large number of the older lots. My sense is that this isn’t codified in an orderly way, however.

So this is a question for the real estate professionals on this forum. If I buy these lots—7,500 square feet with a 50’ width—how comfortable can I be that the person who buys them from me will be allowed to build a house on them? I want to know what your experience has been as far as these smaller lots being exempted from current code minimums. I know that in Mississippi the rule of thumb seems to be that as long as the lot can meet the frontage requirements, construction is permitted.