I’m not a lawyer but I think you have a reasonable gripe. Patb’s comments are sort of true, but you aren’t so concerned about the drainage issue, but about the conduct of the realtor and if you can hold the realtor’s feet to the fire, go for it.

Also, signing something that says you are willing to deal w/ the property “as is” is not the same as signing something that says you waive your right to disclosure.

Maybe talk to a lawyer first to understand the strength of your position. Then call the agent’s broker directly, tell him/her your plans and see if they’ll refund you enough cash to keep you out of court. Definitely threaten to go after damages as well as your legal fees also.