End-on cross-section of a French drain
A cross-section cut across a residential French drain, viewed end-on so the round four inch perforated pipe faces the viewer. Turf is restored on top over a gentle swale, filter fabric lines a trench filled with three quarter inch washed gravel, and rainwater soaks down through the soil and gravel and enters the pipe through perforations all around it, collecting in the bore and running down the pipe, which is sloped to daylight.
YARD DRAINAGE
How a French Drain Works
GENTLE SWALE
TURF RESTORED ON TOP
3/4" WASHED GRAVEL
FILTER FABRIC
4" PERFORATED PIPE
SLOPED TO DAYLIGHT