French Drain Installation Cost Calculator
French Drain Installation costs $1,325 to $1,975 for a typical 60 linear feet job in 2026, against a national benchmark of $1,600. Labor runs 12.6 crew hours at $40.06 an hour. Enter a ZIP code to apply that area's measured wages for this work and its regional price level.
What makes up the price
Cost by size
National averages, before any local adjustment. Computed from the same model as the calculator above, so the two always agree.
| Length of drain | Linear feet of drain | Typical | Range |
|---|---|---|---|
| 30 linear feet | 30 | $1,025 | $825 to $1,250 |
| 50 linear feet | 50 | $1,400 | $1,150 to $1,750 |
| 60 linear feet | 60 | $1,600 | $1,325 to $1,975 |
| 80 linear feet | 80 | $2,000 | $1,625 to $2,475 |
| 100 linear feet | 100 | $2,375 | $1,950 to $2,950 |
Check the downspouts first
A good share of French drain calls are a downspout dumping a roof's worth of water against the foundation. A thousand square feet of roof in a one-inch rainfall sheds about 600 gallons, and a downspout that ends in a splash block two feet from the wall puts all of it into the soil beside the footing.
Before spending $1,600 to $4,000:
- Extend every downspout at least six feet from the wall, ideally ten. Buried rigid extensions to daylight cost a few hundred dollars.
- Check the gutters are not blocked, because a blocked gutter sheets water down the wall.
- Look at the grade. Six inches of fall in the first ten feet. A flower bed that has been topped up over the years until it slopes back toward the house is a remarkably common cause of a wet basement.
If the water keeps coming after all of that is fixed, you have a genuine groundwater problem and a drain is the answer.
Three drains that share a name
| 60 linear feet | Per foot | |
|---|---|---|
| Shallow yard drain | $1,600 | $27 |
| Curtain or perimeter drain | $2,700 | $45 |
| Interior basement drain | $4,000 | $67 |
| 120 ft of yard drain | $2,775 |
| 120 ft of curtain drain | $4,875 |
| 80 ft of interior drain ending at a sump | $6,375 |
A shallow yard drain is a trench 12 to 18 inches deep that moves surface water off a low area. A curtain drain is excavated to the footing outside the wall — three to five feet down — and intercepts groundwater before it reaches the foundation. An interior drain cuts the slab out along the inside of the wall and collects water that has already arrived.
Measure only the walls that are actually wet. Interior drains are frequently quoted around the whole perimeter when two sides are dry, and that is the single easiest way to halve a quote honestly.
Inside or outside: the fork that matters
For a wet basement this is the decision, and the honest answer depends on the house rather than on which is better engineering.
| Exterior curtain drain | Interior drain | |
|---|---|---|
| 60 ft | $2,700 | $4,000 |
| What it does | Stops water before the wall | Manages water that has arrived |
| Also lets you | Waterproof and insulate the wall | Nothing — the wall stays as it is |
| Destroys | Garden, patio, deck, driveway | Nothing outside |
| Needs | Access all round the house | Interior access and a sump |
| Disruption | Weeks, and machinery | Days, and dust |
Exterior is the better fix, because keeping water out of a wall beats pumping it out of a floor, and because with the wall exposed it can be sealed and insulated at the same time. The reason most basement work is done from inside is not engineering: it is that the outside is a deck, a driveway, a zero lot line or a row of mature trees, and that restoring the landscaping often costs more than the drain.
Interior is the pragmatic fix and it works. What it does not do is stop the wall getting wet — which matters if the wall is finished, because the water is still arriving in the block and the system is managing it rather than preventing it.
60% of the quote is digging
Worth knowing because it tells you which questions are worth asking.
The pipe is a couple of dollars a foot. The stone, the fabric and the fittings are a few more. About 60% of a French drain quote is excavation labor, which is why what is in the way matters more than any specification:
| 60 ft yard drain | |
|---|---|
| Open ground | $1,600 |
| Roots, fences, planting beds | $2,000 |
| Under a patio or driveway | $2,400 |
Open lawn lets a trencher run and a 60 foot drain is a day. Roots turn it into hand work — and cutting roots over about two inches on a mature tree is a conversation with an arborist, not a decision for a shovel. Going under paving means breaking it out and reinstating it, or boring beneath it.
Specifications that actually matter
Four, and they are the ones to put in writing:
Fall. A drain needs at least 1% slope — an eighth of an inch per foot — and more is better. A flat drain is a trench that holds water. Ask how the fall will be set and checked, because on a long run across a flat yard it is the constraint that decides whether the drain is possible at all.
Fabric around the stone, not just a sock on the pipe. The classic failure of a French drain is silt filling the stone and blocking it, after which it is a buried trench doing nothing. Non-woven filter fabric lining the trench, with the stone inside it and the fabric lapped over the top, is what keeps silt out. A sock on the pipe alone can clog in silty or clay soils and is not a substitute.
Rigid pipe with cleanouts, not just corrugated. Rigid PVC costs more and can be rodded out in ten years when something does get in. Corrugated pipe cannot be cleaned effectively, and a corrugated drain that silts up is a dig-it-up job. At minimum, insist on a cleanout at each end.
Where the water goes. Daylight to a lower point is the best answer — gravity never fails and there is nothing to maintain. A dry well works where there is no fall and the soil drains, and not at all in clay. A sump and pump works anywhere and makes the drain exactly as reliable as the pump, which is the trade-off set out on the sump pump page.
Where the water must not go
Two that cause real trouble:
- Onto a neighbor's property. Concentrating water and discharging it across a boundary is actionable in most states, and it is the commonest neighbor dispute in drainage work. If the only fall is that way, it needs a conversation and sometimes an easement.
- Into the sanitary sewer. Illegal in most jurisdictions, for the same reason as a sump discharge: it floods treatment plants in storms.
Also worth checking before anybody digs: a utility locate is free in most states and not optional anywhere, and in some areas a drainage discharge needs a permit or has to meet a stormwater rule.
What you are paying for
60 linear feet of shallow yard drain in open ground, daylighting to a slope, at $1,600:
| Labor, about 12.6 hours | around $707 |
| Perforated pipe, stone and filter fabric | $330 |
| Locate, haul-away and site protection | $150 |
| Overhead and margin | the balance |
Note the shape: labor is more than twice the material, and that ratio gets worse as the trench gets deeper. The interior version of the same length is $4,000, of which $2,086 is labor — because breaking out a slab, digging beside a footing and patching the floor is a week of work rather than a day.
Questions worth asking
- Where is the water coming from, and have the downspouts been dealt with?
- Inside or outside, and why that one for this house?
- Which walls are actually wet?
- What fall will the drain have, and how is it being set?
- Will the trench be lined with filter fabric, or just the pipe socked?
- Rigid pipe or corrugated, and where are the cleanouts?
- Where does the water discharge, and is that legal here?
- Who restores the lawn, the patio or the slab?
- Is a utility locate being called in?
- What happens if it still leaks — what is the warranty, and is it transferable?
Common questions
How much does a French drain cost?
About $1,600 for 60 linear feet of shallow yard drain, which is $27 a foot. A curtain drain dug to the footing outside the wall is $2,700 for the same length, or $45 a foot, and an interior basement drain with the slab cut out is $4,000, or $67 a foot. Longer runs are slightly cheaper per foot: 120 feet of yard drain is $2,775 and 120 feet of curtain drain $4,875.
Do I actually need a French drain?
Check the downspouts first. A thousand square feet of roof in a one-inch rainfall sheds about 600 gallons, and a downspout ending in a splash block two feet from the wall puts all of it into the soil beside the footing. Extend every downspout at least six feet out, clear the gutters, and check that the ground falls six inches in the first ten feet. A surprising share of French drain calls are solved by that alone, and if water keeps coming afterwards you have a genuine groundwater problem.
Is an interior or exterior French drain better?
Exterior is the better engineering, because keeping water out of the wall beats pumping it out of the floor, and with the wall exposed it can be waterproofed and insulated at the same time. Interior is cheaper to live through and is often the only option — when the outside is a deck, a driveway, a zero lot line or mature trees, and when restoring the landscaping would cost more than the drain. Interior works; what it does not do is stop the wall itself getting wet.
Why is an interior French drain more expensive than an exterior one?
Because the slab has to come out. An interior drain means cutting and breaking out concrete along the wall, digging beside the footing, bedding pipe in stone, setting a wall board and patching the floor — $67 a foot against $45 for a curtain drain. The exterior figure, though, excludes putting the garden back: once landscaping, a patio or a driveway has to be restored, exterior work frequently ends up more expensive overall, which is why most basement drainage is done from inside.
Why is excavation most of the cost of a French drain?
Because the pipe is a couple of dollars a foot and the hole is not. About 60% of a French drain quote is excavation labor, which is why what is in the way matters more than any pipe specification. Open lawn lets a trencher run and a 60 foot drain is a day; tree roots, a fence line or planting beds turn it into hand work at about 25% more; and going under a patio or a driveway means breaking it out and reinstating it, at about 50% more.
What slope does a French drain need?
At least 1%, which is an eighth of an inch per foot, and more is better. A flat drain is a trench that holds water. On a long run across a flat yard the fall is the constraint that decides whether the drain is possible at all, so ask how it will be set and checked — a laser level or a string line and a measurement, not an eye. If there is no fall available, the design has to end at a sump rather than at daylight.
Should the pipe or the trench be wrapped in filter fabric?
The trench. The classic failure of a French drain is silt filling the stone until the whole thing is a buried trench doing nothing, and what prevents that is non-woven filter fabric lining the trench with the stone inside it and the fabric lapped over the top. A sock on the pipe alone can clog in silty or clay soils and is not a substitute. This is worth putting in writing because it is invisible once backfilled.
Should a French drain use rigid or corrugated pipe?
Rigid PVC where you can afford it, because it can be rodded out in ten years when something does get in. Corrugated pipe cannot be cleaned effectively, so a corrugated drain that silts up becomes a dig-it-up job. Rigid also holds its grade better, which matters when the fall is marginal. At minimum, insist on a cleanout at each end of the run whichever pipe is used.
Where should a French drain discharge?
To daylight at a lower point if there is any fall at all — gravity never fails and there is nothing to maintain. A dry well, which is a stone-filled pit, works where there is no fall and the soil drains, and not at all in clay. A sump and pump works anywhere and makes the drain exactly as reliable as the pump. What it must not do is discharge onto a neighbor's property, which is actionable in most states, or into the sanitary sewer, which is illegal in most jurisdictions.
How long does a French drain last?
Thirty years or more if the trench was lined with filter fabric and the stone was washed; ten or less if silt gets into the stone. That is the whole of the difference, and it is decided on installation day by two things nobody can see afterwards: the fabric and whether the stone was clean. Cleanouts and rigid pipe mean a drain that does start to silt can be rodded rather than excavated.
Can I install a French drain myself?
A short shallow yard drain in open ground is achievable with a rented trencher, a weekend and a strong back — the materials for 40 feet are about $220. Three things catch people: setting and holding a consistent fall, which is the part that decides whether it works; lining the trench with fabric rather than just socking the pipe; and calling in a utility locate first, which is free and not optional. A curtain drain at footing depth or anything involving a slab is not a DIY job.
Will a French drain affect my neighbor?
It can, and it is the commonest dispute in drainage work. Concentrating water and discharging it across a boundary is actionable in most states, even where the water used to flow that way diffusely. If the only available fall is toward a neighbor, that needs a conversation first and sometimes a recorded easement. It is also worth checking whether your jurisdiction requires a permit or has a stormwater rule covering discharge, which some do.
Where these numbers come from
Nothing here is copied from a contractor directory. Labor is priced from what the trades are actually paid, materials from published producer prices, and both are adjusted to your area using federal cost-of-living data.
- All other specialty trade contractors, United States: $40.06/hour, August 2026 (BLS CES CES2023899003)
- Perforated pipe, stone and filter fabric: $5.50 per linear foot (price recorded October 2026, not index-adjusted)