You can sue the seller for fraud.  Fraud is the intentional misrepresentation of a material fact made with knowledge of its falsity and with the intent to induce your reliance upon which you justifiably relied to your detriment.Fraud by the seller also applies to nondisclosure of a material fact which the buyer could not have reasonably discovered.In other words, you would not have purchased the property had you known about the sewer line blockage.Your damages monetary compensation in a lawsuit for fraud would be either benefit of the bargain or out of pocket loss.Benefit of the bargain means that a defrauded purchaser may recover the difference between the real and represented value of the property purchased regardless of the fact that the actual loss suffered might have been less.Out of pocket  determination for fraudulent misrepresentations permits recovery of the difference between the price paid and actual value of the property acquired.