You probably don't need to start your attorney's meter running just yet. Thanks to some pretty clear legal protections, you've got leverage for trying to work things out with the seller first. (That's assuming that you didn't buy the house "as is.")

In most states, it's illegal for a seller to fraudulently conceal a major or "material" physical defect in the property. A "material defect" means something more serious than the odd cracked tile or scratched enamel, but is a defect that could affect the property's value or its residents' health or safety. A basement that turns into a swimming pool during heavy rains fits pretty much anyone's definition of a material defect.

Many states also require sellers to take a proactive role by making written disclosures on the condition of the property. These are normally made on a standard form listing types of possible physical or structural problems. It sounds like your seller was required to fill out such a form.

But the big question here is, did the seller know about the leakage? If not, then he can't be held responsible for failing to tell you about it.

Your best bet now is to work with the contractor you mentioned. If the contractor's work ends up costing you money, contact the seller and ask to be reimbursed. In fact, your best move would be to alert the seller pronto to the situation. Also keep a good paper (or electronic) trail of your communication with the contractor and the seller.

Then if the seller doesn't cooperate, and if you can document that the defect was longstanding and should have been known to the seller, you have a good basis for going to court and recovering damages. If the cost of the damage is over the local small claims court limit, the time has probably come to call your attorney.