Filtration and drainage represent a major area of application for geotextiles. Traditionally they have been used in conventional civil engineering applications and in agricultural drainage. More recently there has been a substantial use of geotextiles as filters in waste disposal applications, particularly in North America. Geotextiles have proven to be very effective in these applications, and this has been well documented in numerous conference proceedings, including the four International Conferences on Geotextiles and Related Products.

Geotextiles prove to be excellent filters in subsurface drainage applications. The needle punch construction of the fabric allows subsurface water to pass into the drainage pipe for proper channeling. At the same time, the geotextile prevents adjacent soil from clogging the system and causing costly excavation and repair. When properly selected, geotextiles are effective in most soils, particularly in environments where silt and clay are prominent.