Perimeter Drains and Curtain Drains:
A curtain drain is a drain used to intercept water moving though the soil. The term “perimeter drain” describes a curtain drain that surrounds an area, making a complete circuit. Perimeter drains are sometimes installed around septic absorption fields to help drain wet soils (absorption fields need well drained soils to function properly).
Perimeter drains usually connect (outlet) to existing field tiles, open ditches or to the ground surface on the side of a slope.
How a perimeter drain is installed:
- A trench is dug where the drain is to be installed (usually at least 10′ from the absorption field).
- A slotted field tile is laid in the trench bottom (the tile is usually 4″ – 6″ in diameter). The tile must maintain a minimum slope (usually .2′/100′) throughout its length until the point of its outlet.
- The trench is then filled nearly to the ground surface with gravel (usually pea-stone).
- The drain is then covered with fill soil.