House bought in November 2014, basement flooded December 2014, backed up drain pipe to sewer line. What are my options?

These types of issues come up often. A lawyer will tell you whether you have a claim against the seller, home inspector, Realtor, or other 3rd parties. Consult an attorney. The facts and circumstances, and particularly, the documents make all the difference. And your damages as well.

You need to provide more facts? Is the leak, potable water or sewage? Is the leak clearly of long existence? Signs of efforts to fix? What did the owner state about the plumbing? Did you have a house inspection? What did the report say? What does your plumber say about this leak? How much is involved in fixing it? What damage resulted? Based upon your answers there may be much that can be done or nothing worth while doing.