Exterior landscaping design is critical for control rain water runoff. In the adjacent slides, several examples of improper finish grading are displayed. Of the many issues that are important, the single most important is the finish grade next to a house.
A negative slope towards a foundation will allow rain water to flow towards a house. This is not what you want around your home. As the soil becomes saturated next to the foundation, whether block or poured concrete, moisture through vapor pressure will move from a higher to a lower concentration. The lower concentration is the basement or crawl space.
Landscape slope toward foundation results in saturated soil.
This side yard has many problems allowing rain water to get to foundation.
Even poured concrete foundations can become wet allowing moisture entry.
Wells that trap rain water from gutters will saturate a basement foundation.
Wells are very common and must be monitored for below grade moisture entry.
Check out this well built for access to a crawl space
Rain water can enter from multiple areas around this well
Standing water next to the foundation. Saturated soil will cause moisture penetration.
Slope towards foundation results in a wet crawl space and even exterior wall.