If you know of this, then yes, you do need to disclose: this is an item that clearly has a material (significant) effect on the value, desirability, use, etc. of the home, and to fail to disclose a known impact on  value, etc. can be to commit fraud and therefore expose yourself to liability. If you did not know, you'd be under no duty to investigage; but since you do know, you have to disclose or risk liability later.