Calculator
French drain cost calculator
Costs split sharply by placement. A yard drain and an exterior foundation drain are the same trench at different depths, and the depth is most of the price.
Typical French drain cost: $900 to $4,000 for a 50 to 100 foot yard drain installed by a contractor, at $18 to $40 per linear foot. Exterior foundation drains run $60 to $120 per foot, or $6,000 to $12,000 per 100 feet, before the outlet and any surface restoration.
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National ranges for 2026, before regional adjustment. Metro labor rates swing this ±30%. Use it to judge whether a quote is reasonable, not as a substitute for one.
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Three local contractors, no cost to you. Useful mainly as a sanity check against the number above — quotes on the same job routinely vary by 40%.
French drain cost per foot
The calculator above prices by placement. Installed by a contractor, a yard French drain runs about $18 to $40 per linear foot, a curtain drain intercepting hillside water $25 to $55, an interior basement system $50 to $95, and an exterior foundation drain $60 to $120. Done yourself, a yard or curtain drain drops to $6 to $16 per foot in materials, because pipe, gravel and fabric are cheap and the contractor price is mostly labor and machine time.
Those are the per-foot rates the estimator uses. Multiply by run length, then add the outlet and any restoration.
French drain cost by length
| Drain type | 25 ft | 50 ft | 100 ft | 200 ft |
|---|---|---|---|---|
| Yard or lawn drain | $450–$1,000 | $900–$2,000 | $1,800–$4,000 | $3,600–$8,000 |
| Curtain drain | $625–$1,375 | $1,250–$2,750 | $2,500–$5,500 | $5,000–$11,000 |
| Interior basement perimeter | $1,250–$2,375 | $2,500–$4,750 | $5,000–$9,500 | $10,000–$19,000 |
| Exterior foundation drain | $1,500–$3,000 | $3,000–$6,000 | $6,000–$12,000 | $12,000–$24,000 |
| DIY yard drain (materials) | $150–$400 | $300–$800 | $600–$1,600 | $1,200–$3,200 |
A basement perimeter is usually 100 to 160 linear feet, which is why interior systems land between about $6,000 and $18,000 once a $1,000 to $3,000 sump is included.
DIY vs contractor
Materials are the small part of the bill: perforated 4-inch pipe, washed 3/4-inch stone and non-woven filter fabric come to roughly $6 to $16 per foot. A contractor charges the difference for machine time, spoil removal and the guarantee that the pipe actually falls toward the outlet, at least 1 inch per 8 feet. For a shallow yard run with good access, DIY is realistic. For anything at footing depth, or next to a wall that is already moving, it is not.
What actually moves the price
Depth, first and last
A yard drain at 20 inches and a footing drain at seven feet are the same pipe in the same gravel. The second costs three to five times more per foot because of excavation volume, spoil handling, shoring, and the fact that a machine has to reach a wall it cannot stand on top of.
Restoration is the invisible half
Trenching under a lawn costs a few dollars a foot to put right. Trenching under a paver patio, a concrete walkway, or a driveway means demolition and replacement, and that line alone can rival the drain. When comparing quotes, check whether restoration is included or excluded — this is the most common reason two bids on identical work land thousands apart.
The outlet
Daylight is free. A dry well is $1,500–$4,000. A sump system is $1,000–$3,000 installed, plus a battery backup you should not skip, plus the electrician if there is no circuit nearby.
Interior versus exterior
Interior basement systems run roughly half the cost of exterior excavation and can be done in winter without destroying the landscaping. They also do not stop water reaching the wall — they collect it after it arrives. If the wall itself is failing, interior work manages a symptom that keeps getting worse. More on that decision.
Check the cheap fix first. A meaningful share of "I need a French drain" jobs are downspouts discharging beside the foundation. An extension costs $40. Confirm that is not your problem before spending four figures, and start with where the roof water goes.
French drain cost questions
How much does it cost to put in a French drain?
A contractor-installed yard French drain costs $18 to $40 per linear foot, so $900 to $2,000 for a 50-foot run and $1,800 to $4,000 for 100 feet. Exterior foundation drains cost $60 to $120 per foot because the trench goes down to the footing. Add $1,000 to $4,000 if the water needs a sump or dry well instead of draining to daylight, and more if the trench crosses a patio or driveway.
How deep is a French drain?
A yard drain is usually 18 to 24 inches deep, a curtain drain intercepting water from a slope 2 to 3 feet, and a footing drain goes to the bottom of the foundation, typically 4 to 8 feet. Depth is the biggest single driver of cost, because every extra foot multiplies the soil that has to be dug, moved and put back.
Are French drains worth the money?
They are worth it when water collects on the surface after rain, runs onto the lot from uphill, or saturates the soil beside the foundation. They are not worth it when the real cause is a downspout discharging next to the house, a problem a $40 extension fixes, or when there is no downhill outlet and the budget does not stretch to a sump or dry well.
Where should you not put a French drain?
Avoid running one where it has nowhere to discharge, across a septic drain field, through a mature tree root zone, or so that it dumps collected water onto a neighboring property, which can create legal liability. Call 811 before digging so buried utilities are marked.
Can I install a French drain myself?
A shallow yard or curtain drain is a reasonable DIY job with a rented trencher: materials run $6 to $16 per foot. Foundation-depth drains are not. Trenches deeper than 5 feet need shoring to be safe, and a mistake next to a footing can undermine the wall you are trying to protect.