How To: Dry a Wet Basement

A wet basement can be obvious—water trickling across the floor or standing several inches deep at the base of the stairs. But there also are less obvious signs.

A wet basement may just feel humid and have a damp, stuffy smell. If so, wood in contact with concrete may be wet or decaying. Efflorescence, a chalky white substance left by the evaporation of water, may be seen on the walls. Basement floor tiles may be loose or popped. A carpeted floor may smell musty.

Find the Water

Fixing a wet basement begins with finding the cause. Infiltration of surface water, infiltration of groundwater, presence of outside humidity, and presence of indoor humidity are common causes of wet basements.

Surface water intrusion is when water runs toward the foundation and finds an entry. Groundwater enters through the walls and floor by wicking action or by hydrostatic pressure when the surrounding soil is saturated or the water table is high.

Warm, moist summer air can enter a house and condense on the basement's cooler floor or walls. Indoor activities, like an improperly vented dryer, can create humidity that settles in the basement.

Fix the Problem

To avoid ongoing problems with mold or mildew, get rid of any water-damaged furnishings and possessions unless they can be properly cleaned. Then identify and treat the source of the problem.

Surface Water

If surface water is the culprit, watch how the roof drainage system works and where rain water flows during a rainstorm.

A gutter or downspout plugged with debris may be sending rainwater over the gutter, down along the foundation, and into the house. Regular cleaning or installing a product that prevents debris from getting into the trough will end that problem.

If there is no debris but rainwater is still overflowing, the downspouts may be clogged, incorrectly sized for the roof area, or insufficient for the size of the house. Consider getting larger gutters, adding another downspout, or increasing the downspout size and its corresponding gutter opening.