Interior Perimeter Drain

Interior perimeter foundation drains are designed to collect the water that enters through the foundation wall or rises to the slab and divert the water away from the home. Perforated plastic drain tiles are placed on the interior side of the footer, below the slab. The pipe is covered with a minimum of 6 inches of gravel or crushed stone. The surface water that penetrates the foundation wall or groundwater that rises to the slab is directed to the interior drain below the slab where it is captures. The captured water is then directed to either a storm sewer, dry well or, if necessary, to a sump pump to be discharged away from the home.

Generally, the system is only placed next to the one or two walls that experience the water penetration problems. However, in some severe cases, the system is placed around the entire perimeter. In addition, to help prevent sediment from entering and clogging the drain tile, a filter paper is placed around the pipe (especially the openings) or gravel.

Interior perimeter drains are often connected to sump pumps that direct the water to the exterior.