looking for litigation lawyer to file compaint against seller of the house

we moved in to newly bought house and very next day we realized that there is some problem with sewer line. Its a split level house(no basement) so if I use water anywhere in the house water is backing from dowstair (groundlevel) bathroom shower drain. Major plumbing company try to snake it and put camera in but they said there is blockage where it connects with main line, and estimation for the work is 18000$ onwards. we are out of our house and staying in temporary rentingas plumbing company said cant use water until its done cant use water in the house. now we want to file coplaint against seller as we belive they sold the house with pre-existing condition. please advise