It's important not to allow moisture to build up or flow underneath your home. Moisture can cause a lot of problems, including erosion, mold, and wood rot. It can also make the environment more attractive to rodents and insects.

If it's a ground water drainage problem, you'll need to reroute the water so that it no longer flows under the house. Usually a french drain system will do the trick.

A french drain is a trench that intercepts flowing or seeping water before it can reach your home. A typical system will involve a trench dug at a two- to three-foot depth, lined with about a foot of field rock on the bottom. A perforated pipe (with the holes positioned at the top) is laid down into the trench, and covered with another 6 to 12 inches of six inches of rock, a layer of septic field sand filter paper, and one more layer of rock.

The idea is to pick up the water as it approaches the high side of the lot and move it along the side of the home, dropping it off at the low side. The captured water can lead to a dry well, a storm drain, or into a rain garden.