Sellers are legally required to disclose any known deficiency to the buyers. Unfortunately, not all parties will agree on exactly what constitutes a deficiency, so your safest bet is to disclose everything that may be considered a flaw.
While it is by no means a complete listing of potential problem areas, this checklist provides a good starting point for identifying possible liability problems in your home.
Inspections
What if the boiler fails a month after the closing? Even if you knew nothing about the problem chances are the buyer will think you did - and even the most diligent seller is going to have a hard time countering this accusation. A pre-sale home inspection can help. Problems discovered by the inspector can be repaired or disclosed - and it is very believable that the seller was unaware of any problems that a qualified inspector was unable to find.