On porous walls, such as those constructed of cinder blocks, you may find damp spots. Masonry-block walls are constructed with interior voids, but when the hydrostatic pressure on the exterior portion of the wall is high, the voids will often fill with water. As a result, the wall may be rather wet to the touch. However, keep in mind that this condition may also be caused by condensation.
The areas most vulnerable to water seepage are the cracks and the joints around pipes passing through the wall, such as the inlet water pipe and the drainpipe leading to the sewer. Examine these areas closely for water streak stains and efflorescence.
If properly constructed, a poured concrete foundation is supposed to be more watertight than a concrete-block wall. More often than not, however, it is not properly constructed. If the entire wall is not constructed with a single pouring, the joints between the sections constructed with each pour are susceptible to water seepage. If the joint is not properly prepared for a new pour, a cold joints with a poor bond will be formed.
Look for signs of seepage in a poured concrete wall around the tie-rod holes in the wall, around the small-diameter metal rods that are used to hold the forms together when the wall is being poured. These holes are generally patched over. Moreover, these tie rods can corrode away in time and when below grade, making them vulnerable to water intrusion. Efflorescence and water streaks may occur just under the hole or patched sections. Sometimes, these holes are plugged with corks, however this is not considered a permanent patch. If seepage develops, they should be plugged with hydraulic cement.