French Drain Cost in 2026: Interior & Exterior Pricing Guide

Water problems don't fix themselves — they get worse. A French drain is one of the most effective and permanent solutions for yard drainage and basement waterproofing. Here's exactly what it costs, what's involved, and whether DIY is realistic.

The short answer: a French drain costs $25–$100 per linear foot installed. Exterior French drains (yard drainage) run $25–$65/ft. Interior French drains (basement waterproofing) cost $50–$100/ft. For a typical project, expect to pay $1,500–$5,000 for exterior and $5,000–$15,000 for a full interior perimeter system.

A French drain is simply a gravel-filled trench with a perforated pipe that collects and redirects water. The concept is 150 years old and it still works better than most modern alternatives. The catch is that proper installation matters enormously — a French drain built wrong can actually make drainage problems worse by creating a channel that directs water toward your foundation instead of away from it.

I've installed French drains in everything from suburban backyards to commercial properties, and the difference between a drain that works for 30 years and one that clogs in 3 is entirely about technique and materials. Let me walk you through the real costs and what to look for.

1. Average French Drain Costs

2. Exterior French Drain Costs

Exterior French drains are trenched into the ground outside your home, either in the yard (to redirect surface water) or along the foundation (to intercept groundwater before it reaches basement walls).

Yard French Drain (Shallow)

Shallow yard French drains solve surface drainage problems — standing water after rain, soggy areas of the yard, water pooling near patios or walkways. They're typically 12–18 inches deep and 6–12 inches wide. The trench is lined with filter fabric, partially filled with gravel, the perforated pipe is laid on the gravel bed, and the rest is filled with gravel and topped with soil or sod.

Deep Foundation French Drain (Footing Drain)

Foundation-level French drains (also called footing drains or drain tiles) are a major project. The crew excavates down to the foundation footing — typically 6–8 feet deep — installs the drain pipe alongside or on top of the footing, adds gravel and filter fabric, and backfills. While the foundation is exposed, it's the perfect time to apply waterproofing membrane and repair any cracks.

3. Interior French Drain Costs

Interior French drains (also called interior drain tile, perimeter drainage, or basement waterproofing systems) are installed inside the basement, beneath the concrete floor, along the perimeter walls.

Interior systems work by collecting water that seeps through or under the foundation wall, channeling it through the perforated pipe under the floor, and directing it to a sump pump pit where it's pumped out. A drainage board or membrane is installed against the wall to guide any wall seepage down into the drain channel.

The concrete is cut 12–18 inches from the wall, removed in a strip, the trench is dug, pipe and gravel installed, and fresh concrete poured over top. When it's done, all you see is a thin line in the concrete where the cut was made.

4. Components & Materials

Gravel: Don't Skimp

The gravel is as important as the pipe. Use clean, washed 3/4-inch stone (also called #57 stone). Don't use pea gravel (too small, shifts and packs), crushed limestone (fines clog the pipe), or river rock (too large, creates voids). Washed stone allows water to flow freely to the pipe without carrying fine particles that cause clogging.

Pipe: Corrugated vs. Rigid

Corrugated HDPE pipe is cheaper, flexible, and easy to work with — ideal for shallow yard drains. Rigid PVC pipe is more durable, handles more weight (important for deep drains under driveways or near foundations), and has smoother interior walls that resist clogging. For any drain deeper than 2 feet or near a foundation, use rigid PVC.

5. Labor Costs

Equipment costs are a significant factor for deep drains. A mini excavator rental runs $250–$500 per day (plus delivery). A concrete saw for interior work is $100–$200/day. Hauling and disposing of excavated soil and concrete debris adds $200–$600 per project.

6. Cost by Project Size

7. Factors That Affect Price

• Depth: Deeper drains cost exponentially more. An 18-inch shallow drain costs $25–$50/ft. A 6-foot foundation drain costs $40–$65/ft. An 8-foot deep drain costs $50–$80/ft.
• Soil type: Sandy soil is easy to dig. Clay is harder and slower. Rocky soil may require a hydraulic breaker, adding $5–$15/ft.
• Access: If heavy equipment can't reach the work area, hand-digging adds 50–100% to labor costs.
• Existing landscaping: Mature trees, garden beds, patios, walkways, and fences in the path of the drain add removal and restoration costs ($500–$5,000).
• Discharge location: The drain needs somewhere to go. Running the discharge to a storm drain, dry well, or daylight outlet adds $200–$1,500 depending on distance and complexity.
• Permits: Some municipalities require permits for French drain installation, especially if connecting to the storm sewer system ($50–$300).
• Utilities: Underground utilities in the trench path require hand digging around them. Always call 811 before digging.

8. DIY French Drain Guide

Exterior French drains are one of the best high-value DIY projects for homeowners. The technique is simple — it's the physical labor that's demanding.

DIY Step-by-Step

1. Call 811: Have underground utilities marked. This is free and legally required. Wait for all utilities to be marked before digging.
2. Plan the route: Start at the problem area (where water collects) and run downhill to a discharge point at least 10 feet from the foundation. Minimum slope: 1% (1 inch drop per 8 feet of run).
3. Dig the trench: 12–18 inches deep, 6–12 inches wide. Rent a trencher ($150–$300/day) for anything over 30 feet — hand digging gets old fast.
4. Line with filter fabric: Drape non-woven geotextile fabric across the trench with enough excess to wrap over the top later.
5. Add base gravel: 2–3 inches of washed 3/4" stone on the bottom. This creates a drainage bed under the pipe.
6. Lay the pipe: Place perforated pipe (holes facing down) on the gravel bed. Ensure consistent downhill slope.
7. Fill with gravel: Cover the pipe with at least 4 inches of washed stone on all sides.
8. Wrap the fabric: Fold the excess filter fabric over the gravel to prevent soil from migrating into the stone.
9. Backfill: Top with 2–4 inches of topsoil and seed or sod. Or leave the gravel exposed for a visible drain channel.

9. Alternatives to French Drains

Before installing a French drain, rule out simpler solutions. Many drainage problems are caused by clogged gutters, short downspouts discharging next to the foundation, or negative grading (ground sloping toward the house). Fixing these costs $100–$500 and often eliminates the problem entirely.

10. Maintenance & Lifespan

A properly installed French drain requires minimal maintenance and lasts 30–50 years. Here's what to watch for:

• Annual inspection: Check discharge point for blockage. Clear any debris or sediment from catch basins. Check for standing water above the drain line (indicates a clog).
• Root intrusion: Tree roots can infiltrate perforated pipe. Don't plant trees within 10 feet of a French drain. If roots are a problem, copper sulfate root killer ($10–$15) can be flushed through the system annually.
• Sediment buildup: Over time, fine particles can migrate through filter fabric and build up in the pipe. Professional jetting/flushing costs $200–$500 and is recommended every 5–10 years for drains in heavy clay soils.
• Gravel settling: In exterior drains, the surface above the drain may settle over time as gravel compacts. Top up with additional gravel or topsoil as needed.

11. Hiring a Contractor

French drain installation is done by waterproofing contractors, drainage specialists, landscapers (for exterior drains), and general contractors. Here's what to look for:

Must-Haves

• Licensed and insured: Workers' comp and general liability. If an uninsured worker is injured on your property, you're liable.
• Drainage experience: Ask specifically about French drain installations. A general landscaper may not understand proper slope, gravel sizing, or pipe orientation.
• Written warranty: Minimum 5-year warranty on labor. Reputable waterproofing companies offer 10–25 year or even lifetime warranties.
• Detailed written estimate: Should specify pipe type, gravel specification, trench dimensions, discharge location, and restoration scope.

Get Multiple Quotes

Drainage work is notoriously variable in pricing. I've seen the same 100-foot interior French drain quoted at $5,000 by one company and $14,000 by another. Get at least three quotes. The lowball quote isn't always the best — but neither is the highest. Ask each contractor to explain their approach and materials, and go with the one who gives you the most confidence in their expertise.

12. Frequently Asked Questions

How much does a French drain cost in 2026?

A French drain costs $25 to $100 per linear foot installed. Exterior yard drains average $25–$50/ft ($1,250–$5,000 for a typical project). Deep foundation drains cost $40–$65/ft. Interior basement drains cost $50–$100/ft ($5,000–$15,000 for a full perimeter system).

Are French drains worth the cost?

Absolutely, when you have a genuine water problem. A $3,000–$8,000 French drain protects against water damage events that cost $10,000–$50,000+. They're one of the most cost-effective waterproofing solutions available, and a properly installed system lasts 30–50 years.

How long do French drains last?

30–50 years with proper installation and materials. The pipe itself lasts indefinitely. Lifespan is determined by clogging resistance — use filter fabric, clean washed gravel, and quality perforated pipe to maximize longevity.

Can I install a French drain myself?

Exterior French drains are a feasible DIY project. Materials cost $5–$12 per linear foot; the main investment is your labor. Interior French drains require concrete cutting and are significantly harder to DIY. For a 50-foot exterior drain, expect to spend $300–$550 in materials versus $1,250–$2,500 professionally installed.

What is the difference between an interior and exterior French drain?

Exterior drains are installed outside in the yard or alongside the foundation to intercept groundwater before it reaches your home. Interior drains are installed inside the basement, under the concrete floor, to collect water that has already entered and route it to a sump pump. Exterior drains are prevention; interior drains are management. Both are effective; ideally you'd have both.

The Bottom Line

French drains are one of the oldest and most reliable drainage solutions in construction. When installed correctly with the right materials, they'll manage water problems for decades with almost zero maintenance.

For yard drainage issues, a shallow exterior French drain is often a great DIY project that costs $300–$600 in materials and a hard weekend of work. For basement waterproofing, hire a professional — the concrete work, proper pitch, and sump pump integration need to be done right.

Whatever you do, don't ignore water problems. Standing water, damp basements, and soggy yards don't improve on their own — they get worse, and the damage compounds with every rain event. A French drain now prevents foundation problems, mold, and property damage that cost 10× more to fix later.