Slotted drains consist of a corrugated pipe with an extended slot, or throat, at the top (see Figure 10-5). The throat of a slotted drain inlet is ordinarily reinforced for structural integrity.

Slotted drains should be installed with sufficient slope to provide a cleaning velocity for the corrugations. If not, regular cleaning and maintenance must be scheduled on the slotted drain. Clean out access boxes are usually needed at the far end of each slotted drain run to facilitate regular maintenance and cleaning.