Your roof has a tremendous surface area that is excellent at collecting water during a rain storm. Hopefully all that water is going to a gutter and eventually to a downspout. Where does the water go once it leaves the downspout? Ideally, the downspout is connected to a perimeter or stormwater drain so that water is taken away from your foundation. Frequently, water is pooling at the downspout and can make its way to your foundation and lead to a very wet crawlspace or structural damage.
Take a look at the downspouts at your house. Are they connected to a drain system or are they able to spew water on the ground next to your house? If the downspout ends at the ground like the above pictures, you have a potential problem. All that water can erode the dirt around the foundation and lead to moisture penetration at the foundation and in to the crawlspace. An easy fix is either a splash block or a downspout extension (pictures below). They need to go at the end of the downspout and placed so that they direct water away from the house.
Brian Jovag, owner of Jovag Home Inspection.