French Drain
Cost Guide 2026

Whether you are dealing with a swampy backyard or a basement that seeps during every storm, a French drain is the gold standard for residential water management. A French drain is a gravel-filled trench containing a perforated pipe that collects and redirects groundwater or surface water away from a foundation, basement, or low-lying yard area. French drain installation costs $10 to $35 per linear foot for exterior yard drains and $40 to $85 per linear foot for interior basement perimeter systems, with the national average project cost at approximately $5,000 in 2026. The total price depends primarily on whether the drain is installed inside the basement (requiring concrete removal and a sump pump) or outside in the yard (requiring excavation and grading).

2026 French Drain Price Breakdown

Cost by Drain Type

Not all French drains are created equal. Here is what each type typically costs and when it makes sense to choose one over the other.

Key Cost Factors

What makes one 50-foot drain cost twice as much as another? These are the variables that matter most.

• Trench Depth: Shallow yard drains (12 to 18 inches) are cheap to dig. Deep foundation drains (6 to 8 feet) require heavy machinery and shoring, adding $15 to $30 per linear foot.
• Obstructions: Driveways, sidewalks, patios, and utility lines add significantly to labor time. Expect $500 to $2,000 extra for each major obstruction.
• Concrete Disposal: For interior drains, jackhammering and hauling away old concrete slabs adds $500 to $1,000 to the total.
• Soil Conditions: Clay-heavy soil drains slowly and may require additional gravel or wider trenches. Rocky soil increases excavation costs by 20 to 40 percent.
• Pipe Material: Standard corrugated pipe runs $1 to $3 per foot. Rigid PVC or heavy-duty options cost $3 to $8 per foot but last longer.
• Sump Pump Addition: Interior systems almost always need a sump pump ($800 to $2,500 installed) to move collected water out of the basement.
• Permits: Some municipalities require permits for drainage work, especially near property lines. Budget $50 to $200 for permit fees.

Interior vs. Exterior: Which Do You Need?

This is the single biggest decision and it determines your final price. Interior and exterior French drains solve different problems, and choosing the wrong one wastes money.

Many homes benefit from both. A complete interior and exterior waterproofing approach catches water from all directions. If budget is tight, start with whichever side is causing the active problem.

DIY French Drain: Can You Do It Yourself?

A shallow exterior yard drain is one of the more achievable DIY drainage projects. You can save 40 to 60 percent on labor costs by doing the digging and assembly yourself. Interior basement drains, however, require jackhammering concrete and installing a sump pump system, which is best left to licensed waterproofing contractors.

DIY Steps for an Exterior French Drain

1. Plan the route. Identify where water collects and map a path to a suitable discharge point (street, dry well, or low area). Maintain a 1 percent slope minimum.
2. Call 811. Always call before you dig to mark underground utilities. This is free and required by law in most states.
3. Dig the trench. Standard depth is 18 to 24 inches, width 6 to 12 inches. Rent a trencher for long runs.
4. Line with landscape fabric. Drape filter fabric along the entire trench with extra material on each side to wrap over the top later.
5. Add gravel base. Pour 2 to 3 inches of washed drainage gravel in the bottom.
6. Lay the pipe. Place perforated pipe with holes facing down on the gravel bed. Connect to a pop-up emitter or discharge point.
7. Backfill with gravel. Cover the pipe with 4 to 6 inches of gravel, then fold the fabric over the top to keep soil out.
8. Top with soil and sod. Replace the topsoil and reseed or sod as needed.

Recommended Products & Tools

These are the drainage products we recommend based on durability, value, and real-world performance. Whether you are tackling a DIY install or just want to understand what your contractor should be using.

Pros and Cons of French Drains

When to Hire a Professional

Call a licensed drainage contractor for any of these situations:

• Trenches deeper than 3 feet or any work near the foundation footing
• Driveway, patio, or sidewalk crossings that require cutting and repair
• Interior basement drain systems with concrete removal
• Properties with known utility lines, septic systems, or well water
• Persistent mold or musty smell issues linked to drainage failure
• Grading or slope problems that require engineering assessment

Maintenance Tips

A French drain is not completely maintenance-free. These simple habits keep your system working for decades.

• Flush the line once a year with a garden hose inserted at the highest point. This pushes out sediment before it hardens.
• Keep the outlet clear of leaves, debris, and soil buildup. Check pop-up emitters after heavy storms.
• Re-grade the surface every couple of years so water keeps flowing downhill toward the drain trench.
• Inspect catch basins quarterly and remove accumulated debris from grates and sumps.
• Watch for settling over the trench line. Depressions can indicate pipe collapse or gravel compaction.
• Test your sump pump monthly if your interior drain connects to one. Pour a bucket of water into the pit to verify it activates. See our troubleshooting guide if it fails.

Frequently Asked Questions

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