"Illegal" Third Unit

[Ryan C.]

I have a possible duplex/triplex I am looking at buying in GA that the previous owners have added an additional third unit to the property.  This third unit doesn't seem to be legal as the property is listed as a duplex.  Has anyone had any experience rezoning a property from a duplex to a triplex to make the property legal?  Or conversely what are the ramifications of leaving the third unit as?

I am looking to buy this with hard money and then refinance it, but that will most likely require it to be zoned correctly in order to secure traditional financing. 

Any help would be greatly appreciated.