How Much Does a French Drain Cost?

Last updated: August 2026 · Reviewed by Nisar Dalvi

Depth is the single biggest driver in that table. A shallow exterior drain under two feet runs $10 to $35 a foot; the same trench taken down to the footings runs $30 to $90. You are paying for cubic yards of excavation, not for pipe.

Which of the five do you actually need?

Before you compare quotes, work out what you are buying. Contractors use these names loosely, and two "french drain" quotes can be for completely different work.

One line to remember it by: swale = shaped dirt · curtain = shallow pipe for surface water · french = deep pipe for groundwater · trench = surface grate for pavement.

Where does the water actually go?

This is the question that separates a real quote from a cheap one, and almost nobody publishes it. A french drain collects water. It does not make it disappear. It has to come out somewhere, and that exit is a line item of its own.

A drainage contractor put it plainly: "Where the water goes matters. A French drain needs an outlet. Sometimes that's a simple pop-up emitter. But in more complex jobs we might need to tie into a dry well, install a sump pump and discharge line, or run 50 to 100 feet of pipe to daylight or a storm drain. The more complex the outlet, the more labor and materials involved."

Is it legal to drain onto your neighbor or into the street?

In Texas, there is a statute, and it is unusually direct. Texas Water Code §11.086:

"No person may divert or impound the natural flow of surface waters in this state, or permit a diversion or impounding by him to continue, in a manner that damages the property of another by the overflow of the water diverted or impounded."

A neighbor whose property is injured "has remedies at law and in equity and may recover damages." Equity includes an injunction — a court order to undo the drainage work you just paid for.

"Surface water" here has a specific meaning: water diffused over the ground from falling rain or melting snow, and it stays surface water until it reaches a bed or channel where water usually flows. Which is exactly what a french drain collects and moves.

Florida takes a different route to a similar place: the reasonable use doctrine, built from case law rather than one clean statute, plus municipal codes that vary by city. The practical guidance is the same in both states — do not design a system whose answer to "where does it go" is "next door."

One more that catches people: discharging into the sanitary sewer is illegal in most jurisdictions. Storm water overwhelms treatment plants during exactly the weather that produces it. If a contractor proposes tying your drain into a sewer cleanout, that is a reason to stop.

What is included per foot, and what is always extra?

The per-foot number conventionally covers the build itself: trenching, filter fabric, gravel, perforated pipe and rough backfill.

A properly built drain goes in as a fabric-lined trench, a gravel envelope around the pipe, then the fabric folded over the top with about a 12-inch overlap, backfilled and graded away from the foundation, with solid pipe carrying water to the outlet and a pop-up emitter if it discharges to lawn.

What is not in that number:

• The outlet — the whole section above. Dry well, sump, or a long run to daylight.
• Restoration. In a contractor's words: "Trenching through sod, mulch, or decorative stone creates a mess. Full sod replacement, new mulch beds, or paver resets add to the cost. On some jobs, restoration can be 15 to 30 percent of the total."
• Spoil hauling — the excavated soil has to go somewhere.
• Permits — see the figures further down.

What makes a quote jump after the site visit?

• Outlet complexity — the single biggest one, and the reason to settle it early.
• Distance to a legal discharge point — 50 to 100 feet of extra pipe is common.
• Depth to the footing on foundation work. This is the $10-a-foot to $90-a-foot jump.
• Hardscape in the trench path — patios, walkways and driveways have to come up and go back.
• Rock and tree roots in the trench line.
• Buried utilities forcing hand-digging instead of machine work.
• Landscaping restoration — that 15 to 30 percent again.

Two real jobs for scale: a 45-foot foundation drain with a pop-up emitter and regrading came to $5,400. A 25-foot drain tied into a downspout came to $3,100.

What does an interior basement system cost?

$4,000 to $17,000 at $40 to $100 per foot, and a crawl space version is $2,000 to $8,000. It is the most expensive version of this job for one reason: the concrete floor around the perimeter has to be broken out, the drain laid, and the slab re-poured.

An interior system always includes a sump pump, and that is not an upsell. The perimeter channel sits below floor level, so collected water has nowhere to go by gravity. It has to be lifted out. If a basement quote does not include a pump, ask why.

Two things worth buying at the same time:

• A battery backup, $600 to $1,200 added to an existing pit. The storms that flood basements are the ones that knock the power out. A mains-only pump is offline for exactly the hour you need it.
• A water-backup endorsement on your insurance, roughly $50 to $150 a year. Without it, a flood claim caused by pump failure is likely to be denied.

Do you need a permit?

If the drain begins and ends on your own property, usually not. If it touches the public right-of-way, a storm system, or involves electrical work, expect one.

These are typical ranges rather than a named county's schedule. Fees are set locally, so call your city before you budget. Inspection fees apply on top wherever you touch the public right-of-way.

How long does it last, and can it be cleaned?

A well-built french drain is pitched to last 20 years or more. Keeping it there takes very little: inspect every two to three years, flush the pipe from an upstream cleanout with a garden hose to move silt through, and check the pop-up emitter, which collects debris and can seal itself shut without anyone noticing.

Questions to ask before you sign

• Which of the five is this? Get the depth in writing, not just the length.
• Where exactly does the water discharge, and is that included in the price?
• If there is no slope, what is your plan — dry well or pump? What does it add?
• Does any of this cross into the right-of-way or a storm system, and who pulls the permit?
• Is there a cleanout at the high end? If not, ask for one.
• What restoration is included — bare soil, seed, or sod?
• What happens to the excavated spoil?

And the one nobody asks: where does this water end up relative to my neighbors? A contractor who has not thought about that has not finished designing your drain.