Water in a crawl space can cause a lot of trouble for your home’s foundation because it causes mold to form, which will rot away at the wood structures in your crawl space and attract wood-eating pests, which will cause even more damage. (We’re going to talk more about this in just a bit.)
If the soil around your home’s foundation is prone to erosion, water in a crawl space can cause damage simply by washing away the soil around and under the foundation. This exposes more of the foundation wall than should be exposed and destabilizes the piers in the crawl space as well.