Damp Basement Walls
It is not unusual that a basement is damp but has no signs of visible liquid water leakage. Many times a homeowner complains about “dampness” issues in their basement that is directly related to humidity problems. If you don’t see actual liquid “water” in the form of streams, puddles or leaks, chances are pretty good that your problem is related to high humidity and not to water leakage.
However, damp walls are also commonly a result of cracks in the foundation walls causing water to seep through. An unpainted block wall will turn dark gray when it’s wet while a painted wall will show discoloration, or a darkening of the paint. A poured wall might show discoloration. In any case, there might be white or dark outlines surrounding the area, which means that either the area has leaked before or substantial moisture has come through in that area.
To learn more about wet basement walls, read: