If the property has an uneven or inadequate amount of grading (slope) then this can prevent water from draining away from the building the way it should. This means that water may start to pool around the foundations of the home, making the basement damp.
Another reason water could collect around the foundations of the home is if gutters and downspouts are either damaged or clogged and leaking. If downspouts were not installed correctly, this could also be contributing to the damp. Ideally, downspouts should be installed so that water drains away from the home, 10 feet is a good amount.
Sometimes the location of a home may be the reason for a damp basement. For example, homes located at the base of a hill or incline may experience water pooling around the home. To help prevent this from happening, some homeowners have small ditches or swales dug about 10 to 15 feet away from their homes which would divert water away from the house.
These are just some of the reasons why a homeowner might experience damp basement issues. However, for a more in-depth assessment, it would be wise to schedule a thorough home inspection.