French Drain Installation Cost Calculator
Estimate a french drain from run length, trench depth, gravel and fabric, plus how water exits the system. Midpoints are residential landscape drains — not municipal storm sewer. Click any i for detail.
Your french drain
Run length (lf)
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Run length
Measure the trench line from collection point to outlet in linear feet. |
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Trench depth
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Trench depth
Deeper trenches move more water in wet soils but cost more to dig and fill with stone. |
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Outlet type
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Outlet type
Daylighting to grade is simplest. Pop-up emitters suit lawns. Tie-ins to existing drains or complex exits cost more. |
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Your state
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Your state
Scales midpoints for typical state-level labor and material costs versus the U.S. average — not an on-site bid. |
Options
How to use this calculator
- Enter linear feet of drain run.
- Choose trench depth and outlet style.
- Keep pipe and fabric checked for a standard wrapped drain.
- Select your state and review excavation vs materials lines.
Results explained
Depth drives excavation and gravel $/lf. Pipe, fabric, and outlet are separate lines so you can see where the bid goes.
Quick reference: french drain $/lf
U.S.-average component midpoints before state scaling.
| Depth | Excavation $/lf | Gravel $/lf | Notes |
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| 18–24 in | $18 | $9 | Shallow landscape drain |
| 24–36 in | $28 | $14 | Common yard standard |
| 36–48 in | $42 | $20 | Deeper interception |
| Pipe + fabric | +$6.50 + $3.25 | — | Typical wrapped system |
Outlet adders: daylight ~$350, pop-up ~$550, complex tie-in ~$1,200.
How the estimate is built
Total ≈ lf × (excav $/lf + gravel $/lf + pipe + fabric) + outlet flat, × state. Band ≈ 80%–130%.
Example scenario
An 80 lf, 24–36 in drain with pipe, fabric, and daylight outlet at U.S. average is about $28 + $14 + $6.50 + $3.25 = $51.75/lf × 80 + $350 ≈ $4,490.
FAQ
Will this fix a wet basement?
It can help surface and footing water when correctly designed. Interior waterproofing or sump work may still be needed.
Do I need a perforated pipe?
Most modern french drains use perforated pipe in a gravel bed wrapped with fabric — unchecking pipe models a gravel-only trench.
Rocky soil?
Hand digging or rock sawing can exceed these midpoints; use a higher-cost state as a stress test.