Moreover, many newer framing materials, such as plywood truss joists, have a much lower resistance to a moisture-induced loss of strength. Start with how the owner stores basement goods. While some homeowners may just be unduly fastidious, a seller's raised storage should raise a prudent buyers suspicions. Look for actual water marks near the base of the foundation walls and at the bottoms of the stair carriages. Next, look for more subtle signs of a water problem.
Loose tiles are often a good indicator or water exposure.
Finally, get a look inside the base of the furnace cabinet, where the filter and blower are. Take off the blower cover and look closely for rust near the floor with a flashlight. The good news is that If you have, or are about to acquire, a wet basement, resolution of the problem is often easy and inexpensive. No foundation is as water-tight as the hull of a ship. If the ground which is in contact with the outer face of the foundation is chronically saturated, water will eventually find its way through any type of foundation.