French Drain Installation Cost: Interior, Exterior, and DIY Options
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How Much Does a French Drain Cost?
French drain installation costs $1,500–$10,000 depending on type, length, and location. Interior basement drains cost more than exterior yard drains due to concrete cutting and sump pump requirements.
| Type | Cost per Linear Foot | Typical Project Cost |
|---|---|---|
| Exterior yard drain (shallow) | $15 – $30 | $1,500 – $5,000 |
| Exterior foundation drain (deep) | $40 – $80 | $4,000 – $12,000 |
| Interior basement drain | $50 – $80 | $5,000 – $15,000 |
| Curtain drain (hillside) | $20 – $40 | $2,000 – $6,000 |
Types of French Drains
Exterior Yard Drain
Solves surface water problems — standing water in the yard, soggy spots, water pooling near the foundation. A trench (12–18 inches deep) filled with gravel and perforated pipe redirects water to a drainage point (street, dry well, or lower area of the yard).
Cost: $15–$30/ft installed. A 100-foot drain: $1,500–$3,000. This is the most common and affordable type.
Exterior Foundation Drain (Footing Drain)
Installed at the base of the foundation to intercept groundwater before it reaches basement walls. Requires excavating down to the footing level (6–8 feet deep). Often combined with waterproof membrane application.
Cost: $40–$80/ft installed. Full perimeter (130 ft for typical house): $5,200–$10,400 plus restoration.
Interior Basement Drain
Installed inside the basement along the perimeter, beneath the floor slab. Captures water that seeps through walls or the floor-wall joint and routes it to a sump pump. Requires cutting and removing a strip of the concrete floor.
Cost: $50–$80/ft installed. Full perimeter with sump pump: $6,500–$15,000.
What’s Included in the Cost
| Component | Cost |
|---|---|
| Excavation | $3 – $15/ft (depth-dependent) |
| Perforated pipe (4-inch) | $1 – $3/ft |
| Filter fabric (geotextile) | $0.50 – $1.50/ft |
| Gravel (washed, 3/4 inch) | $3 – $8/ft |
| Sump pump (if needed) | $300 – $800 installed |
| Backfill and grading | $2 – $5/ft |
| Concrete cutting/patching (interior) | $10 – $20/ft |
| Landscaping restoration | $500 – $3,000 |
How a French Drain Works
The concept is simple: water follows the path of least resistance. A French drain creates an easy path.
- A trench is dug with a slight slope (1% minimum — 1 inch drop per 8 feet)
- Filter fabric lines the trench to prevent soil from clogging the gravel
- Gravel fills the bottom of the trench
- Perforated pipe sits in the gravel (holes facing down)
- More gravel covers the pipe
- Filter fabric wraps over the top
- Soil and/or sod covers everything
Water seeps through the soil into the gravel, enters the perforated pipe, and flows by gravity to the discharge point. The filter fabric keeps fine soil particles from clogging the system.
DIY vs. Professional
DIY Feasibility
Shallow yard drains are the most feasible DIY project. You need: a trenching shovel or rented trencher ($150–$300/day), perforated pipe, filter fabric, and gravel. Budget $500–$1,500 in materials for a 50–100 foot run. Expect 1–2 full weekends of hard labor.
Foundation drains and interior drains are not DIY projects. Foundation drains require deep excavation near the structure (cave-in risk, potential to undermine the foundation). Interior drains require concrete cutting, proper slope calculation, and sump pump installation per code.
| Factor | DIY Yard Drain | Professional |
|---|---|---|
| Materials (100 ft) | $500 – $1,200 | Same |
| Labor | Your time (16–24 hours) | $1,000 – $2,500 |
| Equipment rental | $150 – $300 | Included |
| Total | $650 – $1,500 | $2,000 – $4,000 |
Common Mistakes
- Insufficient slope — needs at least 1% grade. Without it, water pools in the pipe instead of flowing out.
- Wrong gravel — use washed 3/4-inch stone, not pea gravel or crusher run. Fine particles clog the system.
- Skipping filter fabric — soil migrates into the gravel within 2–3 years, reducing capacity.
- No discharge point — the water has to go somewhere. Draining to a neighbor’s property creates legal liability.
- Pipe too shallow — yard drains need 12+ inches of cover. Foundation drains need to be at or below footing level.
FAQ
How long does a French drain last? 15–25 years if properly installed with filter fabric and clean gravel. Without fabric, expect clogging in 5–10 years.
Does a French drain need a sump pump? Only if there’s no gravity outlet. If the drain can flow downhill to daylight (street, lower yard, dry well), no pump needed. Basement interior drains almost always need a pump.
Will a French drain fix my wet basement? An interior French drain with sump pump is the standard fix for most wet basements. It manages the water rather than stopping it from entering, but it’s effective and less expensive than exterior waterproofing.
Do I need a permit? Most jurisdictions don’t require permits for yard drainage. Interior basement drains may require a plumbing permit. Foundation drains near public right-of-way may need city approval for the discharge point. Check locally.
Can I connect a French drain to storm sewers? In some jurisdictions, yes — but many now prohibit it to prevent storm sewer overload. A dry well or rain garden may be required as the discharge point instead.