Legal Question in Real Estate Law in Georgia

Case against who, for what? You chose to not tell us what caused the problem, or how it is the previous owners' fault or what the previous owner concealed or failed to disclose (obviously we all know the contents of the septic tank). You would have to spend quite a bit of money to show that the previous owners were aware of a problem and concealed it. If 5 years passed before you had any problems, that is going to be difficult. If you buy a house, get used to things loike this happening. It is the cost of ownership.

When you bought the home, unless you were negligent, you paid a home inspector to check for such things.

Even so, a problem five years later would be almost impossible to attribute to the former owner.

Absent very unusual facts, and you haven't posted any, I'm doubtful of a claim.