A wet basement wall might be a symptom of a larger problem. Water may be coming in from a variety of sources — leaky downspouts or gutters, blocked drainage pipes, improper grading or ruts that direct ground runoff toward your foundation. Correcting these problems, along with waterproofing your basement walls, is the best way to prevent masonry surfaces from leaking.
You should find out if seepage or condensation is causing your wet walls. To test this, tightly tape a one-foot square of aluminum foil to an interior basement wall, removing it after several days. If the room side of the foil is wet, the problem is condensation. Using a dehumidifier in your basement should help get rid of condensation. If the wall side is wet, the problem is seepage. Both problems can occur at the same time.
Another source of water seepage could be an area often times overlooked — the floor/wall joint. When concrete floors cure, they shrink and pull away from the wall, allowing a space for water to enter. Seal all gaps between floor and walls with hydraulic cement.