The combination of hot long summers (soil dries out) and lots of moisture in winter and spring (saturates the soil) causes the ground to constantly expand and contract.Out of state investors get freaked out by foundation issues but being that its such a normal occurrence, you have a plethora of foundation companies that know how to fix them with relative ease. 

Quads on a septic system is going to be a major expense and you should expect to pump it out every 2 years or so, so it needs a man hole cover.If it is going to be septic be SURE you have sufficient soil quality for your drain field, you will want lots of sand. I

Soil type, adjacent land and what they have on them (spraying chemicals or not).

It might be a good idea to tie the site up as long as you can to get some soil testing and at least some preliminary drawings done by the civil engineer to see exactly what the site work costs will be. 

The Soil Connect app might be helpful.

@Sandy ChauI believe we base it more off tax assessed valueI

"The brighter the dirt the better the soil"6.

Even in Sandy Springs, the original poster's location, investors have to deal with Fulton County injustice.

@Sandy MoralesI've got a duplex, and working on a FULL rehab on a four-plex here in San Antonio. 

Have done any soil testing or build studies so that you can transfer the land in a more opportune way than when you bought it?