French Drain Cost: Interior, Exterior & Yard Drainage Pricing (2026)

Standing water in your yard after every rain. A damp corner in the basement that never fully dries. Soil erosion cutting channels through your lawn. These are drainage problems — and a French drain is often the right fix. The real question homeowners run into is this: you get one quote for $1,800 and another for $9,000 for what sounds like the same job. Both can be correct. The spread comes down to three variables that most contractors do not explain upfront: the type of drain (yard vs. exterior foundation vs. interior basement), excavation depth, and what the water has to do once it is collected. Here is the full cost picture.

French Drain Cost by Type: 2026 Pricing Comparison

The term “French drain” covers three fundamentally different systems. Knowing which one you need is the first step — and choosing the wrong one is an expensive mistake. Per Angi's 2026 national cost database and contractor surveys, here is how each system prices out:

Source: Angi 2026 national cost database, HomeGuide contractor surveys, LawnStarter 2026 pricing data. Costs include materials and labor; permit fees and sump pump systems are additional.

Yard French Drain Cost: Surface and Curtain Systems

Yard French drains are the most common installation and the most accessible for homeowners. The typical setup: a trench 12 to 24 inches deep and 8 to 12 inches wide, lined with filter fabric, filled with 1.5-inch clean crushed stone, centered around a 4-inch perforated PVC pipe, and covered with more fabric and either sod or decorative stone. Water enters through the gravel and pipe perforations, flows by gravity to a discharge point — usually daylight at a lower elevation, a dry well, or a storm drain.

Material Costs for a 100-Foot Yard Drain

• 4-inch perforated PVC pipe: $0.50 to $1.50 per linear foot × 110 feet (with 10% extra) = $55 to $165
• Crushed stone / pea gravel: A 100-foot drain at 12 inches wide × 24 inches deep needs roughly 2.5 tons of stone. At $25 to $55 per ton delivered = $63 to $138
• Filter fabric (geotextile): $0.15 to $0.35 per sq ft × approximately 300 sq ft = $45 to $105
• Drain outlet / end cap: $15 to $40
• Total materials only: roughly $178 to $448 for a 100-foot system

Professional installation of the same 100-foot drain runs $1,000 to $6,500 total — the wide range reflects soil conditions (sandy soil is fast; dense clay or rocky ground is slow and expensive), tree root interference, depth requirements, and access. LawnLove's 2026 national pricing data shows a median of $3,200 for a standard residential yard drain installation.

Exterior Foundation French Drain: The Gold Standard for Water Control

If you have a wet basement and want to address the root cause rather than manage the symptom, an exterior foundation drain is the right answer — and the most expensive one. This system requires excavating around the foundation perimeter down to the footing level (typically 6 to 8 feet for a full basement), installing perforated pipe in gravel, applying waterproofing membrane to the exposed foundation wall, and backfilling. It is a major earthmoving project that typically requires excavation equipment and takes 1 to 2 weeks to complete.

Per RSMeans 2026 residential data, exterior foundation drain installation costs $80 to $200 per linear foot when you include the waterproofing membrane, drainage board, and proper backfill — not just the pipe and stone. For a 120 linear feet of perimeter on a typical home, total project cost runs $9,600 to $24,000. That is significantly more than interior systems, but it solves the problem at the source and adds waterproofing protection to the foundation wall itself.

Interior Basement French Drain: Cost and Process

An interior basement French drain — also called an interior perimeter drain or weeping tile system — does not stop water from entering the basement. It collects water that has already entered at the floor-wall joint (the most common entry point) and channels it to a sump pit for removal. Done correctly, it is an effective permanent solution for active water intrusion. Done incorrectly, it is an expensive failure.

The installation sequence: workers saw-cut the concrete floor 6 to 8 inches from the foundation wall around the perimeter, hand-excavate 12 to 18 inches below the slab, install perforated pipe in stone, seal the channel with hydraulic cement at the wall base, and pour new concrete over the system — leaving only the pipe outlet visible at the sump pit. Per HomeGuide's 2026 contractor data, interior basement French drain installation costs $40 to $100 per linear foot with an average project total of $4,000 to $17,000.

Estimates include drain installation but not sump pump system (add $625–$2,625) or wall encapsulation (add $2,000–$8,000).

Sump Pump Cost: The Necessary Companion

An interior French drain without a sump pump is a collection system with nowhere to go. The drain channels water to a sump pit (typically 18 to 24 inches in diameter, 24 to 36 inches deep), and the sump pump removes it from the structure. Per HomeAdvisor's 2026 national data, sump pump installation costs $625 to $2,625, with most homeowners spending around $1,200 for a quality system. Here is the breakdown:

• Sump pit excavation: $200 to $500 if not included in the drain contract
• Submersible sump pump (1/3 HP): $150 to $450 for quality units (Zoeller M53, Wayne CDU800 are contractor-grade standards). Avoid box-store plastic pumps under $100.
• Battery backup system: $200 to $500 installed — critical for power outages during heavy storms, which is exactly when you need the pump most
• Discharge line installation: $100 to $300 to route water to daylight, storm drain, or dry well
• Check valve: $25 to $75 installed — prevents backflow into the pit when the pump shuts off

I always recommend battery backup on any sump pump in a finished basement. The pump motor typically lasts 7 to 10 years; plan on replacing it at least once during the life of the drainage system.

What Drives French Drain Cost Up or Down

Soil Type

Sandy or loamy soil is easy to excavate and drain well naturally — these jobs come in at the low end of cost estimates. Clay soil is the opposite: it is hard to dig, excavation takes longer (higher labor cost), and clay's poor drainage means you may need a deeper or more extensive system. Dense clay also means excavators cannot simply hand-dig — machine time increases. The Soil Conservation Service soil surveys (available through the USDA Web Soil Survey) can tell you what you are dealing with before you call a contractor.

Discharge Options

A French drain is only as good as its outlet. The three options in order of complexity and cost:

1. Daylight discharge: Pipe exits at a lower point on the property where water can flow out freely. Free if your lot grading allows it. This is the preferred option — gravity does the work.
2. Dry well: A buried perforated container in well-draining soil that allows water to percolate into the ground away from the structure. Installation adds $1,000 to $3,000. Requires adequate soil permeability — clay soils make this ineffective.
3. Storm sewer connection: Connection to the municipal storm drain. Requires a permit and inspection in nearly every jurisdiction. Connection fees and plumbing work add $500 to $2,000.

Utility Conflicts

Always call 811 (or your local equivalent) before any excavation — it is the law. But even after utility marking, French drain trenches often encounter unexpected obstacles: old irrigation lines, abandoned septic pipes, gas lines placed shallower than code, and buried debris from previous construction. Each conflict adds time and cost to reroute the drain. Budget 10 to 15 percent contingency on any exterior excavation project.

DIY French Drain: Realistic Cost and Scope

A yard-level French drain is genuinely DIY-accessible for a motivated homeowner with a free weekend. The key rental is a walk-behind trencher — these can be rented at Home Depot, Sunbelt, or United Rentals for $150 to $300 per day. The machine cuts a precise 4- to 6-inch wide trench to 24 inches deep in a fraction of the time of hand digging.

The slope is the most critical DIY variable. A French drain must maintain consistent fall toward the outlet — a minimum of 1 inch drop per 10 feet of run (1% grade). Use a laser level or a string level to verify grade before you lay pipe. Flat spots or areas that pitch the wrong direction create standing water inside the system, which defeats the purpose and can create mosquito breeding conditions.

Use our Gravel Calculator to estimate how much crushed stone you need before ordering delivery.

Questions to Ask Before Hiring a Drainage Contractor

Drainage work is an area where contractor quality varies enormously. The underlying problem — water — is often not visible until well after installation, which means a bad installation can appear to work for one dry season and fail in year two when you finally get a sustained rain event. Vet contractors carefully:

• What is the pipe specification — perforated PVC (preferred) or corrugated flex pipe (avoid for anything permanent)? Corrugated flex pipe collapses over time under soil pressure.
• Will the system be wrapped in filter fabric to prevent sediment intrusion? No fabric = premature clogging.
• What is the outlet point, and has it been verified to have adequate grade for gravity discharge?
• Is there a warranty, and does it cover the system becoming clogged within the warranty period?
• For interior basement systems: do they carry a lifetime transferable warranty? The top basement waterproofing firms (Basement Systems, BDry, Standard Water Control) typically offer transferable warranties — independent contractors may not.
• Ask for references from projects completed 3 to 5 years ago — not last month. You want to know how the system held up through multiple wet seasons.

Frequently Asked Questions