A wet basement creates an environment that encourages the growth of mold, mildew, viruses and other unwanted organisms. These organisms can have a negative impact on anyone’s health, but especially infants, the elderly and people with weak immune systems. The organisms can also eat away at flooring and wall materials, shortening their useful life. Finally, the moisture can lead to wood rot and termite damage. Fortunately, a wet basement doesn’t have to be a deal-breaker for a prospective homebuyer. Many wet basement problems can be easily fixed, and some can be fixed by the homeowner, saving thousands in professional costs.

The most common cause of a wet basement is soil saturation. This occurs because rainstorms and snowmelt overwhelm the drainage system in the surrounding soil. When this happens, the water table rises, creating pressure against the foundation walls. This pressure is referred to as hydrostatic pressure. When this pressure is high enough, cracks in relatively thin basement walls and floors can form.

Other causes of wet basements include poorly designed landscaping, faulty construction and foundation settlement. Some of these problems can be solved by grading the yard so surface runoff can’t flow toward basement walls, installing French drains to relieve hydrostatic pressure and exterior waterproofing.

If the walls are not leaking and are only damp, it is often possible to stop the problem by cleaning up efflorescence (white deposits of salt) and applying an elastomeric basement wall waterproofing coating. This is generally a do-it-yourself project, although some homeowners may choose to hire a professional for the task. Products like UGL’s DryLok and Xypex’s Hi-Dry cost about $50 per gallon and typically require two or more coats for effective sealing.

In other cases, the groundwater problem is not a result of poor landscaping, but rather because the house was built below the local water table. This is common in older homes, but can occur in newer homes as well. If this is the case, it may be necessary to install an interior floor drain system and use a French drain on the outside of the basement to relieve hydrostatic pressure and protect the foundation.

Another way to solve a wet basement is by using a sump pump. In general, the best pumps are industrial-rated and can handle heavy duty cycles. This solution is not a permanent one, however, as the basement will still need to be drained frequently.