All resales are done on the basis of as-is sale. After closing, you own the property and its condition. That means youâ€™ve got to fix the problem yourself.
If you can prove that there was actual fraud in the deal on the part of the seller or his agents or if you can prove that the inspector you hired (if you did) was negligent, you might have a case. You might also have a large legal bill that will exceed the cost of repairs.
If you did a diligent job of figuring out what you were buying and now find yourself behind the eight ball, I'm afraid that the most likely best response is one of live and learn. As far a sewerage systems go, even if you did purchase or have been given a home warranty policy, I suspect that they will only cover the piping within the walls of the house. I had a client with a broken sewer line in the lawn and it was not covered by the warranty. The seller had had "problems" with the system but it was not until a new family, with a ton more of laundry, started using the system that suds were found that covered the lawn!
Best of luck with this one.