A French drain is a type of drainage system designed to redirect water away from specific areas, such as basements or foundations. It consists of a trench filled with gravel or rock, containing a perforated pipe that collects and channels excess water. This helps prevent flooding and water damage by allowing water to flow away from structures. Typically installed in areas with poor drainage, French drains are effective in managing groundwater and surface water. They can be used in residential and commercial properties to protect landscapes and maintain dry basements, ensuring the longevity of buildings and their foundations.