To maintain the correct humidity level in a basement, place a dehumidifier in the basement, and connect it to the existing main stack, feeder drain or utility sink. If the dehumidifier doesn't measure the level of humidity automatically, place a hygrometer next to it. You can also turn on the exhaust fan when somebody is showering or venting the clothes. The ideal moisture level for a basement ranges from 30 to 50 percent relative humidity.
If the downspouts dispose water too close to the house, extend them to lead water away from the foundation of the house. In addition, make sure that foundation plantings never have too much water around them. If there are cracks or other signs of destruction in the basement walls, repair them to keep water from getting in the basement from outside. You should maintain the correct humidity level in the basement even if it is unfinished; mold and mildew is a common problem in damp basements, which can damage the items in the basement and cause health problems for people living in the house.
When obtaining a dehumidifier, choose it according to the square footage of the basement. The perceived level of dampness is also very important to consider. It may not be necessary to use the dehumidifier in the fall and winter once the weather becomes cool and dry; however, once spring starts and the weather gets more humid, start using the dehumidifier again.