Make sure the ground around the foundation drops 1/2 inch for every foot as you move away from the foundation. The drop should be greater if water flows are heavy in that area. Make sure all concrete patios, walks, and driveways slope away from foundation. Keep gutters clean at all times. During the fall it is better to clean them several times rather than waiting until the end of the leaf season. Make sure the water is not coming down behind the gutters and that the gutters are properly sloped toward the downspouts. Also check that all support brackets and nails are securely in place. Downspouts should discharge water well away from the foundation. If there are any signs of a leak or damaged shingles or flashing, have the roof checked. Generally, if the roof is leaking and is more than 15 years old (with regular shingles), it may be more cost effective to have a new roof put on. Make sure all stairwell drains are clear of debris. Consider building a permanent roof over exterior stairwell to prevent debris and rain from getting into the stairwell. Test your basement sump pump. Make sure all culverts and exterior drains are free of debris.