French drains

Noun

French drain (plural French drains)

1. A shallow trench, sometimes lined with tile or containing a perforated pipe, backfilled with gravel and then covered over, used to collect and channel runoff water.
2. A gravel-filled corridor with a perforated pipe running through it that runs against the foundation footings of a building, used to collect ground water and drain it away from the building's interior.

   Synonyms:

   weeping tile, foundation drain, rubble drain