For most people, runoff is a problem. With a rain garden, it becomes an amenity. Instead of diverting your gutter water into a storm drain, where it picks up motor oil and other urban crud, you can channel it into a low spot on your property planted with bushes, grasses, or trees that like getting their feet wet. Your reward is something beautiful to look at, plus the satisfaction of knowing that you're helping to provide the natural flood-control and water conservation that used to be the job of forests and wetlands.
Find construction details, see How to Build a Rain Garden
. For plant recommendations, contact your local extension office or conservation district, or your state's native plant society.
Total cost for a large rain garden (150 square feet or larger):