Five years old is considered a new roof, so you should get many more years out of it. Speak to a basement person. If moisture rises from the damp earth underneath there would be trouble. Find someone who specializes in basement finishing, because you could end up with a lot of problems with wet carpet due to the stack effect, the moisture rising into the basement floor. From The Virgin Homeowner, I gather that water is perhaps a house's single worst enemy.
Water is the most powerful force in the universe.
The earth is packed down and non-porous until you excavate, and then you have gallons of water dumping down. Finding the leak is like finding the source of the Nile. When home owners think of water it makes all of them grim. Generally, I don't think people cheat you. A good realtor wants you to be happy, and after good research you'll know the value of your house.