French Drain Calculator

Q: How much does a french drain cost?

An exterior french drain costs $10 to $50 per linear foot professionally installed, with most homeowners paying $25 to $35 per foot. A typical 100 ft drain runs $2,500 to $5,000 installed, or $300 to $800 in materials if you dig it yourself. Interior perimeter (basement) systems cost more, at $40 to $85 per linear foot.

Q: What is the cost of a french drain per foot?

Professional installation averages $25 to $35 per linear foot for an exterior drain, covering excavation, pipe, gravel, fabric, and labor. Difficult access, deep trenches, or hard soil push toward $50 per foot. DIY materials alone cost roughly $3 to $8 per foot.

French drains cost $10 to $50 per ft installed, with most exterior drains landing at $25 to $35 per ft, about $2,500 to $5,000 for a typical 100 ft run. DIY materials cost $3 to $8 per foot. Use the calculator to get gravel, pipe, and fabric quantities plus the total cost for your trench.

Estimated total—

Your trench

Drain length

Unit

feetmeters

Trench width (in) Trench depth (in)

Price assumptions

Gravel ($/cubic yd, delivered) Pipe ($/ft) Fabric ($/sq ft) Installation labor ($/ft)

Defaults & assumptions

Defaults: a typical 100 ft drain, 4″ corrugated perforated pipe, and US national average rates. Adjust the rates above to match local quotes. PVC pipe runs about $2.50 per foot. Set labor to 0 for a DIY materials estimate.

Enter your drain length above to see results.

French drain installation cost

A french drain is a gravel-filled trench with a perforated pipe that redirects surface or ground water away from your home. The installation cost runs $10 to $50 per ft for an exterior drain, since excavation and labor are the bulk of it. Materials are cheap: perforated corrugated pipe is about $1.00 to $1.50 per ft, washed drainage gravel $35 to $55 per cubic yard delivered, and non-woven landscape fabric pennies per square foot. Depth matters most: a shallow yard drain sits at the low end, while a deep footing drain with difficult access reaches the top of the range. Interior perimeter systems (basement drains with a sump pump) are a different job at $40 to $85 per ft.

Typical exterior french drain cost by length (US averages)
Drain length	DIY materials	Professionally installed
50 ft	$150 to $400	$1,250 to $2,500
100 ft	$300 to $800	$2,500 to $5,000
150 ft	$450 to $1,200	$3,750 to $7,500
200 ft	$600 to $1,600	$5,000 to $10,000

How the calculator works

Gravel is trench volume (length × width × depth) minus the pipe’s volume, converted to cubic yards and tons. Fabric lines both trench walls and the bottom with a 12 in top overlap. Costs are quantities times your rates; labor is priced per linear foot, the way contractors quote it. Price ranges reflect published US averages from national cost guides (Angi, HomeGuide, LawnStarter, 2026). Extras not included: catch basins (about $50 to $150 each), pop-up emitters (about $25), and sod repair over the trench. See our sod calculator for that.

French drain cost FAQ

How much does a french drain cost?

An exterior french drain costs $10 to $50 per ft professionally installed, with most homeowners paying $25 to $35 per ft. A typical 100 ft drain runs $2,500 to $5,000 installed, or $300 to $800 in materials if you dig it yourself. Interior perimeter (basement) systems cost more, at $40 to $85 per ft.

What is the cost of a french drain per foot?

Professional installation averages $25 to $35 per ft for an exterior drain, covering excavation, pipe, gravel, fabric, and labor. Difficult access, deep trenches, or hard soil push toward $50 per foot. DIY materials alone cost roughly $3.00 to $8.00 per ft.

How much gravel do I need for a french drain?

Multiply trench length by width by depth to get cubic feet, subtract the pipe volume, and divide by 27 for cubic yards. A typical 100 ft drain with a 12 in wide, 24 in deep trench needs about 7 cubic yards (10 tons) of washed drainage gravel.

Is it cheaper to install a french drain yourself?

Yes. Labor is 70 to 85 percent of the professional price. DIY materials for a 100 ft drain (perforated pipe, gravel, landscape fabric) cost roughly $300 to $800, versus $2,500 to $5,000 installed. The trade-off is the digging: a 100 ft trench is 7 cubic yards or more of excavation by hand or rented trencher.