How much does a French drain cost?

DIY exterior yard drain: $5-$10 per linear foot ($250-$500 for a 50-foot drain). Professional exterior yard drain: $25-$60 per linear foot ($1,250-$3,000 for 50 feet). Professional foundation perimeter drain: $3,000-$10,000+ (requires excavating around the foundation). Professional interior basement drain + sump pump: $3,000-$8,000+. The biggest cost for professional installation is labor (digging the trench). DIY saves 60-80% because you supply the labor. Materials (pipe, gravel, fabric) are inexpensive.

Can I install a French drain myself?

Yes, an exterior yard French drain is a very common DIY project. Tools needed: shovel or trencher (rent a trencher for $200-$300/day for long runs), level, wheelbarrow, and basic tools. Time: 1-2 days for a 50-foot drain (longer without a trencher). The work is physically demanding (digging the trench is the hardest part) but straightforward. An interior basement French drain is more complex (jackhammering the basement floor, routing the drain to a sump pit) and is typically a professional job. Foundation perimeter drains require excavating around the foundation — also a professional job.

How long does a French drain last?

A properly installed French drain (with landscape fabric and clean washed gravel) lasts 20-40+ years. The pipe itself lasts indefinitely (PVC) or 20+ years (corrugated). The most common cause of failure: clogging from sediment, roots, or debris. Prevention: use landscape fabric to wrap the gravel and pipe (critical), use clean washed gravel (not dirt-contaminated fill), and keep the inlet and outlet clear. Signs of failure: water ponding in the same area again, slow drainage, or water backing up. If a French drain fails, it can sometimes be flushed with a high-pressure hose. In severe cases: replacement is needed.

Do French drains work in clay soil?

Yes, but they are especially important in clay soil. Clay soil drains very poorly (water sits on top instead of percolating through). This makes French drains more necessary but also requires some adaptations: dig the trench wider (12 inches minimum, wider is better in clay), use more gravel (the gravel provides the drainage path that clay cannot), make sure the landscape fabric is high quality (clay particles are very fine and can clog through cheap fabric), and ensure proper slope (1% minimum — water will not move through clay on its own). In heavy clay: consider a wider trench with a sock-wrapped pipe (a fabric sleeve pre-installed around the pipe) for extra filtration.

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French Drain Installation Guide: Design, Materials & Cost

Lumberama Editorial Team, Drainage & Landscaping Specialists Jul 15, 2026 12 min read

What Is a French Drain

A French drain is a gravel-filled trench with a perforated pipe that redirects water away from a problem area. It works by gravity: water flows downhill into the trench, enters the perforated pipe through small holes, and is carried to a discharge point (a storm drain, dry well, or lower area of the yard). French drains solve: standing water in the yard, water pooling against the foundation, soggy areas that never dry out, and basement water intrusion (interior French drains).

Types of French Drains

Exterior/yard French drain: Installed in the yard to redirect surface water or shallow groundwater. Typically 12-24 inches deep and 6-12 inches wide. The most common type for solving soggy yard problems.

Foundation French drain (footing drain): Installed around the exterior perimeter of the foundation at footing level. Collects water before it enters the basement. Usually installed during construction or as a major retrofit (requires excavating around the foundation).

Interior French drain: Installed inside the basement along the perimeter of the foundation walls. Collects water that seeps through the walls or floor, directs it to a sump pit, and a sump pump ejects it. The most common solution for existing basement water problems (less invasive than exterior excavation).

Materials

Perforated pipe: 4-inch perforated PVC or corrugated pipe (corrugated is flexible and easier to work with; PVC is more durable and resists crushing). The pipe is laid with holes facing down (the water rises into the pipe from below).

Landscape fabric: Wraps the trench to prevent soil and sediment from clogging the gravel and pipe. Use a non-woven geotextile fabric. Critical for longevity — without fabric, the drain clogs within a few years.

Gravel: 3/4-inch washed crushed stone or river rock. Do NOT use pea gravel (too small, migrates into the pipe) or limestone (can cement over time). You need enough to fill the trench around and above the pipe (typically 1-2 tons per 50 linear feet of drain).

Fittings: End caps, couplings, 90-degree elbows (for corners), and a pop-up emitter or outlet at the discharge point.

Installation Steps

Plan the route: determine where water collects (the inlet) and where it will discharge (the outlet). The drain must slope downhill at a minimum of 1% grade (1 inch of drop per 8 feet of run). Mark the trench path with spray paint or stakes.
Dig the trench: 12-24 inches deep, 6-12 inches wide. Wider and deeper = more capacity. Check the slope with a level or laser level as you dig.
Line the trench with landscape fabric, leaving enough excess on each side to wrap over the top later.
Add 2-3 inches of gravel at the bottom of the trench.
Lay the perforated pipe on the gravel (holes facing down).
Fill the trench with gravel to within 2-3 inches of the surface.
Fold the landscape fabric over the top of the gravel.
Cover with topsoil, sod, or decorative stone.