Learn the main French drain mistakes that DIYers make and how to avoid them.
The wrong fabric may not allow water to drain into the perforated pipe.
Not using filtration fabric in a French drain is a major mistake because sediment will rapidly clog the drain.
David Beaulieu / The Spruce
Drainage fabric acts as a separator between the soil and the drainage filler material.
Line the French drain trench with non-woven drainage fabric explicitly designed for drains.
This punch in of fabric provides the correct porosity and drainage flow rate.
Avoid using wovenlandscape fabricfor French drains.Landscape fabric is intended for weed controland should not be used with French drains.
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Using Solid Pipe
Using solid pipe in the French drain trench is a common mistake.
This mistake is easy to make since solid corrugated pipe looks like perforated corrugated pipe at first glance.
Solid pipe will not allow water to pass through the French drain.
Use 4- or 6-inch diameter perforated corrugated (ridged) drain pipe.
Examine the pipe carefully for the perforations, which appear as short slits.
Or it may entirely prevent water from percolating downward.
The larger stones avoid packing together.
The rounded texture ensures that there will always be spaces between the stones.
A 1-percent slope means that it drops 1 foot vertically for every 100 horizontal feet.
Without a discharge station, the drain may also back up within the pipe and stop flowing altogether.
Identify a good discharge station for the French drain: a drainage ditch, swale, or dry well.
Or you’ve got the option to discharge the French drain onto the side of a slope.
You may be able to discharge the French drain to a city or other public storm drain.
Check with your municipality before doing so.
The catch basins must be attached to solid (not perforated) PVC, ABS, or corrugated pipe.
Placing extremely heavy items like buildings on French drains may also impact the pipe and filler.
It’s fine to occasionally drive over a properly installed French drain that’s 18 inches deep or lower.
But give a shot to avoid frequently driving over the drain or parking on it.
Avoid siting buildings over French drains.
Not only may this impact the pipe and filler but it also reduces the drainage area.
A French drain should be buried 18 inches below ground level.
The drain must start at 18 inches and slope downward at a 1-percent or greater angle.
The French drain should end at a discharge station.
You should not cover a French drain with dirt.
Covering a French drain with dirt will clog the fill material, impeding water flow.
