If you think condensation might be a problem in your basement, there is a simple test. Securely tape a 10" x 10" piece of plastic wrap onto the basement wall in an area where you have noticed dampness, sealing the edges of the plastic wrap with the tape.

Check on the plastic over the next few days. Eventually you will get moisture: if the moisture is on the wall side of the plastic, you've got a leak; if the moisture is on the room side of the plastic, you've got a condensation problem.

by David Hollies, reprinted courtesy of HomeAdvisor.com