How to Install a French Drain: Step-by-Step for Yard and Lawn

By Andrea · August 2026

French drain installation follows the same core logic whether you're fixing a soggy lawn corner or a longer perimeter run: dig a trench, bed it with gravel, lay perforated pipe, wrap in filter fabric, and route water to a downhill outlet. This page covers the sequence, materials, and the mistakes that cause systems to fail within a few years. For French Drain For Yard Drainage cost specifics or Yard Drainage Solutions comparisons, see those dedicated guides.

Before You Break Ground

Call 811 before any digging — free utility marking is legally required in every U.S. state. Confirm your outlet is downhill and open to daylight at a lawn edge, swale, or street drain. Flat lots with no gravity outlet may need a Yard Drainage Sump Pump as part of the system. Check local codes — some municipalities require a permit when drainage work redirects water off your property. Full cost context by depth and region is on the French Drain Installation Cost guide.

Materials You'll Need

• Perforated pipe — 4-inch diameter handles the vast majority of residential lawn installs; go larger only for high-volume or very long runs
• Washed gravel (clean crushed stone, ¾-inch is typical) — not pea gravel, which compacts and clogs
• Non-woven geotextile filter fabric — wraps the gravel bed to keep fine soil particles out of the stone over time
• Solid outlet pipe — connects the perforated run to the discharge point; PVC is standard
• End cap or outlet grate — keeps rodents and debris from entering the pipe at the daylight end

1. Mark and Excavate the Trench

Mark the trench line from the wet area to the outlet point. Width is typically 12 inches; depth depends on what you're intercepting. Surface runoff from a lawn needs 12–18 inches. Subsurface water from a high water table requires 24–36 inches, which also means more gravel and longer dig time. Rent a walk-behind trencher for straight runs in accessible yards — it's faster and keeps the trench width consistent. Rocky or clay-heavy ground may require hand digging or a mini-excavator.

3. Lay Fabric, Gravel, Pipe, and Backfill

Before lining the trench, verify a continuous downhill grade of at least 1% (roughly 1 inch of drop per 8 linear feet) using a laser level — a trench that rises and dips will collect standing water and silt up within a few seasons. Then line the trench with filter fabric, leaving enough overhang to fold over the top later. Add 3–4 inches of gravel as a bed, lay the perforated pipe with holes facing down (water rises through the gravel and enters from below), cover with gravel to within 3–4 inches of the surface, fold the fabric over, and top with topsoil. Skipping the fabric is the most common DIY shortcut and causes clogging within 3–5 years.

Lawn French Drain Specifics

For yard applications, the trench typically follows the edge of the wet zone or runs across the slope above the problem area to intercept water before it pools. Herringbone layouts — smaller lateral trenches feeding a main run — work well for broad low spots. Keep the fabric-wrapped gravel envelope intact at every junction; sloppy tee connections are a common failure point. See French Drain For Yard Drainage for layout options and cost by yard size.

DIY vs. Hiring a Contractor

A 20–30 foot run in accessible soil with a clear daylight outlet is a realistic weekend DIY project. Beyond that — clay soil, long runs, tight access, or anything near a foundation — the slope math and excavation get complicated fast. Getting the grade wrong doesn't show up immediately; the system drains fine for a year, then silts up just when you've replanted over it. For anything over 50 linear feet or near a foundation, a licensed drainage contractor is the safer call.

Wet walls or basement floor seepage are a different problem from a soggy yard — hydrostatic pressure at the footing level requires an interior perimeter system, not a yard drain. See basement French drain cost for what those systems involve and what they typically run.