Tip #1) Install downspout extensions to keep rain and storm water away from the crawl space. Tip #2) Clean your gutters annually. Leaves and other debris collect in your gutters, causing them to overflow. Tip #3) Keep foundation clear. Keep plants at least 2 feet from your foundation walls and mulch at least 6 inches away. Water can soak into the mulch and get into your crawl space. Tip #4) Check the grade. The earth should slope away from your house. If you see evidence of water puddling near the foundation, doing some grading can help prevent this from getting into your crawl space or basement. Tip #5) Construct a swale ditch. For yards that are flat, constructing a swale ditch can help divert water away from your crawl space or basement. Sometimes you need a professional do additional moisture control even with all these helpful tips.