The yard is sloped, and the sand is eroding from underneath the house. its a concrete slab foundation, and it seemed that most of the house was sitting on level ground. however, the very front of the concrete slab that connected the front door to the driveway is where erosion of the sand is occuring. is this a nightmare one should stay far away from, or is it fixable?

Will do soil test. 

My brother in law had that problem after hurricane Sandy a few years back.Another way is to grade your property and have water flow away from the foundation.

If you don't have public sewer access, then you must rely upon onsite disposal and that can be limited by the soil types on your land, the size of your parcel, onsite well for water, conservation area requirements, set-backs, and the county health department or State environmental department granting a permit for onsite septic.

Unfortunately one of them was to the above ground oil tank.Can anyone recommend a soil testing and remediation (hopefully don’t need those services) company in southern NJ?

Live in Alpharetta, office in Sandy Springs and do lots of flips from Hapeville to Buckhead.

You should also consider buying in Oklahoma City, you'll get more property for your money and better cash flow than Sandy Springs but probably not as much appreciation.

Good soils, soil health, proper drainage, climate, etc. would be contributing factors to high value land for agricultural use.

The only non-paint issue I have come across is that there can be no bare soil next to the house.

That one involved removing trees and trucking in a lot of soil as the lot wouldn't perk.