A French drain is simple in concept and easy to get wrong in ways that don't show up for two or three years.
The failures are almost always the same three things: not enough fall, the wrong stone, or fabric installed backward. Any one of them turns a drain into a buried trench full of mud.
The machine handles the digging and the stone. The rest is getting the details right.
Before You Start
Call 811. Drainage runs cross the yard and pass close to the house, which is where every service lateral converges.
Find where the water goes. A drain has to discharge somewhere — daylight on a slope, a dry well, or a storm connection where permitted. If you don't have an outlet, you don't have a drain, you have a buried reservoir. Sort this before you dig anything.
Check whether you can discharge where you plan to. Discharging onto a neighbor's property creates liability and, in many places, legal problems. Connecting to a municipal storm system usually requires permission.
Confirm the fall you have. Run a string line and level from the inlet end to the outlet. A commonly used minimum is about 1% grade — roughly 1 inch of drop per 8 to 10 feet. Less than that and water sits.
What You'll Need
Attachments: Trencher for consistent depth, or bucket for wider trenches · Bucket for stone · Harley rake for restoration
Materials: Perforated pipe, non-woven filter fabric, clean washed drainage stone (typically 3/4" washed, no fines)
Steps
1. Mark the run and check the grade end to end. Confirm continuous fall toward the outlet before you cut.
2. Cut and save the sod on a tarp if you're crossing lawn. Replacing original sod heals far better than seeding.
3. Trench to depth, maintaining fall. A trencher holds consistent depth better than a bucket. Check grade as you go rather than at the end — correcting a reverse slope after the fact means redigging.
4. Line the trench with filter fabric. Non-woven, and lay it so you can wrap it over the top of the stone later — like lining a taco. The fabric goes around the stone, not around the pipe. Sock-wrapped pipe alone clogs at the pipe; fabric around the stone keeps silt out of the whole aggregate bed, which is what actually does the draining.
5. Add a base layer of washed stone, a few inches, and verify the fall on top of the stone.
6. Lay the pipe. Perforations down is the conventional practice — water enters low and the pipe fills from the bottom, which uses the full pipe cross-section. Maintain continuous fall. Solid pipe for the last section to the outlet.
7. Cover with stone to the specified depth, then fold the fabric over the top and overlap it.
8. Backfill. Soil over the wrapped stone, or continue stone to the surface if you want a visible drain that also captures surface water. Compact lightly.
9. Restore. Sod back, or seed with an erosion blanket on slopes.
10. Confirm the outlet is protected. Rodent guard or grate, and rip-rap or a splash area so the discharge doesn't erode.
Common Mistakes
No outlet, or inadequate fall. The two failures that make the drain useless from day one.
Wrong stone. Clean washed stone only. Stone with fines packs and clogs. This is the most common material error.
Fabric around the pipe instead of the stone. Sock-wrapped pipe in a bare trench silts up. Wrap the aggregate.
Woven fabric instead of non-woven. Woven geotextile is for soil stabilization, not filtration. Use non-woven for drainage.
Digging blind near the house. Laterals converge at the foundation.
Discharging onto a neighbor. A legal problem, not just a neighborly one.
Not checking grade during the dig. A reverse slope in the middle of a run is invisible until it fails.
Which Yellow Jacket Model
YJ1000 / YJ1100 — residential drainage work. Narrow enough for side yards, enough capacity for stone hauling.
YJ1200 — better for larger drainage projects and stone volume. Wide track, more capacity.
Both trenching and stone hauling are the machine's strengths here — the trench is the labor, and the stone is the weight.
FAQ
How deep should a French drain be?
Depends on what you're intercepting. Surface water drains can be shallow; drains intercepting subsurface flow or relieving a foundation go deeper. The controlling factor is usually maintaining fall to the outlet — depth at the inlet end is often set by how deep you need to be at the far end.
How much fall do I need?
About 1% minimum is commonly cited — roughly an inch per 8 to 10 feet. More is better where the site allows.
What stone should I use?
Clean washed drainage stone, commonly 3/4 inch, with no fines. Fines are what clog it.
Perforations up or down?
Down is standard practice. Water enters at the bottom and the pipe carries at full capacity.
Do I need fabric?
Yes, and around the stone rather than just the pipe. Non-woven filter fabric is what keeps silt out of the aggregate.
Can it tie into my downspouts?
Often yes, but consider volume — roof water is a lot of water fast, and a drain sized for groundwater may not handle it. Many installers run downspouts in separate solid pipe.
How long will it last?
Properly built, decades. The failures are almost always installation errors rather than wear.