Excavated soil that is replaced around a completed foundation isn’t as dense and tightly packed as undisturbed soil farther away. As a result, water collects in the soil immediately surrounding the house, putting pressure on foundation walls and causing cracks.
A sizeable hole was dug in the ground when your home was built. The foundation was then poured, which left a gap between the foundation walls and the existing earth. This gap was filled with soil that was removed and “fluffed up.” This soil is looser, more aerated than the surrounding soil, which may have been compressing for hundreds of years. Thus, the looser soil tends to absorb more water than the compacted soil. More water against the walls leads to hydrostatic pressure. (Source: Bob Vila)