Water that is allowed to run from your gutter and downspouts directly into the ground can cause a flooding that may end up in your craw space or basement and can wear away the soil alongside the house, causing settling of the structure. To redirect water away from your house and stop the flooding, you can use splashblocks, flexible plastic sleeves attached to the downspouts, or plastic drainage pipes that can carry water to a dry well located several yards away from your home.
Downspout Extenders: An extender are attach directly to the downspout. Extenders are made from aluminum, galvanized steel, or vinyl. They are constructed to carry the water away from the house, often into a drain. You can purchase a downspout extender at any home improvement center.
Splashblocks: An alternative to downspout extenders, splashblocks are placed below the elbow of the downspout. Splashblocks are ready-made with concrete or plastic. Ideally, the splashblock should extend at least 4 feet and should be slightly sloped so that the water runs well ahead of the house foundation.
Dry Wells: If you live in a wet climate, you may want to connect your downspouts to a dry well. Locate the dry well 10 or more feet from your home. The well itself can be merely a hole 2 to 4 feet wide and 3 feet deep. Or you can bury a 55-gallon drum after piercing it with holes and removing both ends. Fill the well with rocks or broken concrete, and then cover the top with a wood plank or heavy roofing paper. The well’s top should be at least 18 inches under ground with the bottom above the water table.
The underground drainage pipes should slope ¼ to ½ inch per foot. This allows the water flow from the house downspout to the dry well.