Foundation Drainage Cost: Gutters, Grading, Drains
Foundation drainage work costs $1,500 to $12,000 depending on scope. Compare grading, downspout extensions, french drains, and sump pumps.
Foundation drainage costs $1,500 to $12,000. Regrading and downspout work sits at the low end, a french drain runs $2,000 to $6,000, and a full exterior system with sump pump can reach $12,000.
- Basic regrading and downspouts
- $1,500 - $4,000
- French drain
- $2,000 - $6,000
- Sump pump installed
- $600 - $3,000
- Full exterior system
- $8,000 - $12,000
- Crawl space encapsulation
- $3 - $8 per sq ft
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Foundation drainage costs $1,500 to $12,000, and the low end does more work than most homeowners expect. Extending downspouts and regrading the soil solves a large share of wet-basement complaints for under $4,000. The expensive scope, a full exterior drain system with a sump pump, is reserved for sites where water has nowhere else to go.
What Counts as Foundation Drainage
Foundation drainage is the collection and redirection of surface and groundwater away from the structure before it reaches the foundation wall. It includes roof water, surface runoff, and subsurface water, and each one has a different fix and a different price.
Roof water is the cheapest problem to solve. One inch of rain on a 1,500 sq ft roof produces about 935 gallons, and every gallon that lands next to the wall becomes hydrostatic pressure. Downspouts that dump at the corner are the single most common cause of a wet basement in a house with no other defects.
Price by Scope
| Scope | Typical cost | What it does |
|---|---|---|
| Downspout extensions | $150 - $600 | Moves roof water 4 to 6 feet away |
| Regrading | $1,500 - $4,000 | Builds a 6-inch fall over 10 feet |
| French drain | $2,000 - $6,000 | Collects subsurface water along the footing |
| Sump pump | $600 - $3,000 | Lifts collected water out and away |
| Full exterior system | $8,000 - $12,000 | Drain, gravel, fabric, sump, discharge |
The full system number is not the sum of the rows above because the work overlaps. A french drain installation already includes the trench, gravel, and fabric that a separate line item would price on its own.
Regrading and Downspouts First
The building code baseline most inspectors cite is a 6-inch drop in the first 10 feet from the wall. That is a 5% slope, and it is enough to move surface water away without making the lawn look like a ski hill.
If your yard is flat or slopes back toward the house, regrading is the first spend. A typical job moves 8 to 15 cubic yards of soil along one or two sides. At $40 to $90 per cubic yard installed, including hauling and compaction:
12 cu yd × $60 = $720
Add labor for hand finishing, sod, and disposal, and the total commonly lands at $1,500 to $4,000. That is a fraction of what interior waterproofing costs, and it fixes the cause rather than the symptom.
When a French Drain Is the Answer
A french drain is a gravel-filled trench containing a perforated pipe that collects groundwater and carries it to a discharge point. It is the right tool when water is coming through the footing rather than over the top of the soil, which usually shows up as a damp band at the base of the wall or a basement that smells musty after every rain.
Installed along one side of a house, a french drain typically runs $2,000 to $6,000. The variables are length, depth, discharge destination, and access. A drain that can daylight to a slope costs less than one that must feed a sump pit and be pumped.
The Comparison That Matters
| Approach | Cost | Addresses | Limitation |
|---|---|---|---|
| Regrading | $1,500 - $4,000 | Surface water | Does not touch subsurface water |
| French drain | $2,000 - $6,000 | Subsurface water | Needs a discharge point |
| Interior waterproofing | $4,000 - $12,000 | Water already inside | Does not reduce exterior pressure |
| Crack injection | $400 - $1,200 | A specific leak | Does nothing for the water source |
Most wet basements need two of these, not one. Regrading plus downspouts solves surface water. A french drain plus a sump pump solves subsurface water. Crack injection seals the path but not the pressure, so it is usually the last step, not the first.
A Full Example
A 1,800 sq ft colonial has a damp wall on the north side. The contractor proposes regrading that side, extending four downspouts, and installing a 45-foot french drain feeding a new sump pit.
- Regrading: 10 cu yd × $65 = $650 in material, plus $1,200 labor and disposal = $1,850
- Four downspout extensions at $90 each = $360
- French drain: 45 ft × $85 per ft = $3,825
- Sump pump installed: $1,400
Total: $1,850 + $360 + $3,825 + $1,400 = $7,435
That total sits in the middle of the $1,500 to $12,000 range and reflects a real mixed scope rather than a single line item.
What to Do Next
- Walk the perimeter during a heavy rain and photograph where water ponds and where downspouts discharge.
- Measure the slope at each wall with a 4-foot level and a straightedge; a 6-inch drop over 10 feet is the target.
- Clear gutters and confirm every downspout discharges at least 4 feet from the wall.
- Get two quotes that separate surface work from subsurface work.
- Ask where the discharge point is and confirm it is legal in your municipality.
Keeping the Cost Down
Do the cheap work first and give it a season. Regrading and downspout extensions cost a fraction of a drain system, and if they solve the problem you never buy the drain. If the wall is still damp in the same place after a wet spring, the water is coming from below and the drain is justified.
Read drainage repair around a foundation for the inspection sequence, and compare french drain versus sump pump before choosing which one carries the water. If the wall is already bowing, drainage alone will not correct it, and the cost discussion moves to wall anchors.
Frequently asked questions
How much does foundation drainage cost?
Most drainage projects run $1,500 to $12,000. Simple regrading and downspout extensions cost the least, while a full exterior drain system with a sump pump sits at the top.
What is the cheapest way to improve drainage?
Extending downspouts 4 to 6 feet from the wall and regrading the soil to a 6-inch drop over 10 feet are the lowest-cost fixes and address the most common cause of wet basements.
Does a french drain stop basement leaks?
It reduces hydrostatic pressure against the wall, which is the driver behind many leaks. It does not seal cracks, so crack injection is often done at the same time.
How much does a sump pump cost installed?
A submersible sump pump with pit, discharge line, and check valve typically runs $600 to $3,000 installed, depending on whether the pit already exists and where the discharge can go.
Is drainage work covered by insurance?
Usually not. Most homeowners policies exclude water damage from poor maintenance, grading, and surface drainage, so drainage improvements are typically paid out of pocket.
How long does drainage work take?
Regrading and downspout work takes one to two days. A french drain around a house usually takes three to five days, and a full exterior system can run a week or more.
Sources
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