Drain System for a Raised Bed on Concrete: Pipe to Patio Drain

Building a brick raised bed on a concrete patio with a 4" slab. Need drainage that exits through the slab to the patio's existing drain hole—not through the wall.

Simple, Reliable Design

1. Perforated underdrain pipe at planter low point
2. Solid pipe connects to patio drain outfall
3. Vertical overflow pipe or high-side weep holes for flood safety

Slope everything ¼" per foot minimum. Wrap perforated pipe in filter fabric. Test with a hose before backfilling.