Undisclosed Sewer Issues

[Reagan Huefner]

Do I have a case?

I bought my first rental property in December last year. It is a Duplex in the Uintah Basin, Utah. My wife and I moved in to one unit and rented the other to the tenant already living there. After a couple months the sewer backed up into the tub and onto the floor a bit. We had a plumber come rotoroot the lines and thought that would fix the issue. The tenant in the other unit mentioned that before we bought the place there was usually plumbers there several time a year. This was not disclosed by the seller. Just today the sewer backed up again and I had a plumber Camera the line. Turns out the line has backward slope and does not connect to the main sewer line, but ends in a hole that is full. In order to fix it right will cost about 20k. 

I believe the fact that they were having issues with the sewer should have been disclosed, and if they knew about the real issue then that definitely should have been. Should I approach the seller and ask them to split the cost? Should I take them to court? I would appreciate any additional suggestions. Thanks!