What is a curtain drain?

A curtain drain is a subsurface trench designed to catch groundwater traveling downslope and divert it away from a house, driveway, or other vulnerable area. The trench runs perpendicular to the slope's fall line (the path water naturally flows down) and typically contains perforated pipe surrounded by gravel or stone to allow water to enter and move laterally along the drain line.

Unlike a French drain, which manages water that collects in a low spot or around a foundation, a curtain drain intercepts groundwater before it reaches the problem area. This preventive placement makes it especially valuable in Connecticut's hilly terrain and clay-heavy soils, where spring seepage and subsurface flows can saturate yards and threaten basements year-round.

The drain can be installed at various depths depending on site conditions and water table location. Water collected by the curtain drain is typically channeled to a daylight outlet lower on the property, a storm drain, or a dry well, depending on local codes and grading.

Proper siting and installation are critical to effectiveness. Landscape contractors and drainage specialists assess the slope angle, soil composition, and spring locations to place the trench where it will actually intercept the flow. A curtain drain installed in the wrong location or with inadequate slope may fail to solve persistent moisture problems.