A small opening that allows water to drain from within an assembly. Weeps are located at the bottom of the object to allow for drainage; the weep hole must be sized adequately to overcome surface tension.
Weep holes may also be necessary for a retaining wall so water can escape from the retained earth, thus lessening the hydrostatic load on the wall and preventing damage to the wall from the excess water weight and possible moisture damage from freeze/thaw cycles.
