About 60 percent of homes in the United States have a wet basement, according to the American Society of Home Inspectors. The effects of a wet basement are numerous—from a humid room to destroying everything inside, costing anywhere from a few hundred to a few thousand dollars to fix. A leaky basement can also be a sign of more serious structural problems, such as a cracked foundation.
The cost to stop a leaky basement depends on what type of problem you have. A cracked foundation that lets in subsurface seeping water costs about $1,500 to $2,500. You might need an underground drainage system that consists of four-inch, perforated drains around the home that send water back into the street—this costs anywhere from $15,000 to $20,000 in 2009, according to Amy Brown-Bowers of Bankrate.com. On the other hand, a moist basement might only require a heavy-duty dehumidifier worth a few hundred dollars.
You can solve most basement leak problems yourself, especially if you only have condensation or runoff. Condensation occurs when warm, moist air contacts cool waters and cold water pipes. Put foil over a damp spot for a day—if water forms on the outside of the foil you have a condensation problem, according to John Wagner of This Old House. A humidifier, or waterproof coating, at about $20 per gallon, for the basement walls can fix this.
Rainwater or melted snow forms runoff that can pass through foundation walls or come up out of cracks and gaps. If your basement is damp after a rainstorm or snowfall, you probably have a problem with runoff water. Look for cracks that might let water into the home, such as in the driveway, which can let water gather below your foundation. The ground surrounding the home should slope down one inch for every horizontal foot, according to Wagner. You can patch foundation and basement wall cracks with a tube of polyurethane masonry caulk, which costs less than $20. If you have water gushing into your home or ground water swelling into the basement, you probably need a professional to fix or at least diagnose your problem.
Clean out your gutters. Gutters and the slope of the soil leading away from the home lead to up to 90 percent of basement leaks, according to The Hartford Courant. When you call in a professional, handle one problem at a time, because you might have several issues with the basement, but only one causing a significant problem. Overall, the cost of fixing a leaky basement depends on your tolerance for moisture. If you must have a perfectly dry base, expect to pay more than if you just want to get out most of the moisture.