If you are going to spend $295 on leak detection, I would recommend getting a soil engineer out there instead who will locate the leak, can make sure you weren't lied to on the disclosures statement and can make a recommendation as to what needs to be done to correct or mitigate if anything. I am heavily involved in two foundation cases right now, and people waste so much money on french drains, landscapers, ect....without first getting a soil engineer when he can come in there and identify the problem and provide a solution. I got a bill from one for @$500 last week so it isn't really cost prohibitive. If he says you were lied to and something needs to be remediated, you will already have an expert's report in case you consider litigation.

my .02.