My husband and I put a down payment on what we thought was our dream home, but right after the closing, the roof caved in during a storm! It turned out the roof wasn't structurally sound. Are we responsible, or are the people who sold us the house on the hook? We never moved in. Is it too late to stop the sale?
Once the deal has closed, the house is yours, warts--or in this case, puddles--and all. Courts are reluctant to rescind home sales in general, and in this case, the contract between you and the seller is no longer in play.
However, unless you bought the house "as is," you may still be able to go after the sellers, and possibly the home inspector, for the costs of repairs.
The key question is whether your sellers actually knew about the problem and then either concealed it or failed to affirmatively disclose it. Most states' have disclosure laws in place, which mandate that sellers warn buyers in advance of material defects found within the home. (See, for more information on these laws, How to Review Seller Real Estate Disclosures.)
But even these state disclosure laws don't typically give home sellers any obligation to investigate conditions that they did not notice by themselves. One would think the sellers would have noticed a leaky roof, but this is a fact question. If, however, you can find evidence that the sellers did know about the faulty roof and concealed it or failed to disclose it, you can ask for reimbursement of the costs of repair, and contact an attorney if the sellers refuse your request.
Your home inspector may also be liable for repair costs if he or she could have seen the problem but didn't. This could be viewed as a failure to meet professional standards, in which case you could demand (and eventually sue for) any resulting damage amounts. You'll probably need to hire another inspector to visit your house and to review your inspector's reports, and then consult an attorney about taking legal action.