How much does a french drain cost in Northern Virginia in 2026?

As of 2026, a professionally installed yard french drain in Northern Virginia typically costs about $30 to $70 per linear foot, a curtain drain cut across a slope roughly $35 to $80 per foot, and an exterior foundation-side drain excavated to the footing with waterproofing about $100 to $250 or more per foot. Those are typical market planning ranges for Fairfax, Loudoun, Prince William and Arlington, not myYardPros prices or quotes.

The spread is wide because two drains of the same length can be very different holes in the ground. One is 18 inches deep in open lawn with a gate wide enough for a mini excavator and a curb 20 feet away to drain to. The other is 30 inches deep in clay between townhomes, with 90 feet of solid pipe needed to reach daylight. Below we break the ranges down by drain type, show what moves the number, work three typical lot situations, and list what a low quote usually leaves out. Our french drain installation page explains how we build them.

Short runs cost more per foot because mobilization, the outlet and restoration are fixed costs spread over fewer feet.

A french drain that lasts on clay has six parts, and the price has to cover all six. First, a trench cut to a consistent fall, typically at least 1 percent, which is about 1 inch of drop for every 8 feet, running the whole way to the outlet. Second, a non-woven geotextile lining the trench so clay fines cannot migrate into the stone; Virginia Cooperative Extension notes that in some fine sandy and silty soils gravel filters or synthetic drainage envelopes are often required to prevent drain clogging, and on clay the same fabric keeps fines out of the stone. Third, a bed of clean, washed, angular stone below the pipe. Fourth, the pipe itself: 4 inch perforated pipe, either rigid PVC with holes down or dual-wall corrugated pipe, laid on the stone and pitched with a level. Fifth, more washed stone over and around the pipe to within a few inches of grade, with the fabric folded over the top. Sixth, an outlet lower than the trench: daylight on a slope, a pop-up emitter near the curb, or a storm structure where the county allows it.

With Washington Dulles averaging 43.24 inches of precipitation a year in NOAA's 1991 to 2020 climate normals, and clay that stays saturated for days after each storm, as the wet backyard article explains, the stone volume and the outlet matter more than anything else.

Seven things explain most of the gap between bids on the same yard. Depth is first, because every extra 6 inches across a 60 foot run is about a cubic yard of clay out and a cubic yard of stone in. Stone volume is second and follows depth and width. Pipe type is third: rigid PVC costs more than corrugated and is easier to pitch accurately and to flush. Outlet distance is fourth and the most underestimated. A drain that can daylight 15 feet away is cheap; one that needs 80 feet of solid pipe to reach the street doubles the trenching. Utility conflicts are fifth. Virginia 811 marks public lines, and the gas and cable services that cross a side yard often force hand digging for part of the run; private lines such as irrigation and landscape lighting are not marked and must be located separately.

Restoration is sixth. Laying sod over 60 feet of trench costs real money, and in a bed, mulch and replanting do too. Access is seventh: a 36 inch gate between townhomes in Herndon or Centreville means hand tools and wheelbarrows instead of a mini excavator.

The first two situations are solved from the yard side. The third is only worth it after cheaper exterior fixes have been ruled out.

The side yard drain is mostly labor. Forty feet of trench by hand is a long day for two people, the stone is about 4 tons, and the emitter and sod finish it. The backyard curtain drain is a different shape. Eighty feet of perforated pipe cut 30 inches deep on the uphill side intercepts water moving down the slope before it reaches the low spot, and the two downspouts get their own solid pipe so roof water never enters the perforated line. The daylight outlet is shared, which is the main saving.

The foundation-side drain is a construction project, not a drainage install. Excavating to a footing 7 or 8 feet down along 60 feet of wall means shoring or benching the clay, removing anything attached to the house in that run, waterproofing the wall, placing the pipe and stone, backfilling in lifts and regrading so surface water runs away. Most wet basements in Northern Virginia are caused by downspouts, grading and surface water, so we price the exterior fixes first and reserve the footing drain for houses where water still enters after those are done.

A low quote usually leaves things out rather than lying about what is in. The most common gap is the outlet. A quote that says drain to the property line is a quote for a trench full of water. The second gap is stone. Crusher run or stone dust packs tight and holds water; washed, open-graded stone is what drains, and it costs more. The third is fabric; without it, clay silts the stone within a few seasons. Then come the smaller omissions:

• Depth. A drain pitched from 12 inches at the start can be 6 inches deep at the outlet. Ask for start and end depths.
• Pipe. Thin corrugated pipe with a sock, laid flat, is the cheapest option and the one that fails first on clay.
• Haul-off. Some bids spread the clay on your lawn or leave it in a pile.
• Restoration. Sod, mulch and replanting are often excluded or listed as owner responsibility.
• Downspout separation. Roof water piped into a perforated drain floods it; it belongs in its own solid line, as the downspout drainage page explains.

Ask every bidder to state each of these in writing.

Materials for a 50 foot yard drain typically run $600 to $1,500 as of 2026: about $150 to $300 for 4 inch rigid perforated pipe and fittings, $250 to $500 for 5 tons of washed stone delivered, $50 to $100 for non-woven fabric, $30 to $60 for a pop-up emitter and cleanout, and $150 to $350 to rent a walk-behind trencher or a mini excavator for a day. The same drain from a contractor commonly lands between $1,500 and $3,500, and the saving is almost entirely labor.

Weigh that against three things. Virginia 811 asks for notice at least three working days before any digging and marks only public utility lines, so private irrigation and lighting lines are on you. Pitch is unforgiving; a trench that rises half an inch over 10 feet becomes a long puddle underground. And the outlet has to exist. If the only low point is a neighbor's yard, the storm sewer or a dry well on clay that will not percolate, the problem is design, not digging, and the dry well versus french drain versus catch basin guide is the place to start.

A yard french drain by itself generally does not need a building permit in Northern Virginia; the state building code regulates structures, and none of the county permit pages we checked list a yard drain. Three other rules can apply, though. The first is land disturbance. Fairfax County requires an approved site-related plan for projects that equal or exceed 2,500 square feet of disturbance, and counts a 10 foot work zone around the project plus a 10 foot access path toward the total; it exempts individual home landscaping, as interpreted by staff. Arlington County sets the same 2,500 square foot threshold and adds a survey certification for projects between 2,000 and 2,499 square feet. Prince William uses 2,500 square feet including incidental access areas, and Loudoun's grading permit starts at 5,000 square feet. A single drain rarely gets there; a drain plus regrading plus a new patio can.

The second is the Resource Protection Area. Within about 100 feet of a stream or wetland, counties require approval before any land disturbance, and an outlet that discharges into the buffer gets reviewed. The third is where the water goes. Discharging onto a neighbor's lot invites a dispute, and connecting to a public storm structure needs the county's or VDOT's permission. The patio and retaining wall permit guide covers the disturbance math in detail.

A french drain is the wrong purchase when the water is arriving on the surface, not through the soil. If a downspout dumps 500 square feet of roof onto the lawn, the fix is a buried solid line to daylight at $15 to $35 per foot, not a perforated drain that will simply fill with roof water. If a low spot ponds after every storm because the grade tips toward it, regrading or a catch basin with a solid pipe out is cheaper; our guide to french drains versus catch basins walks through that choice.

A french drain is the right purchase when soil stays saturated between storms, when water seeps from a slope into a flat area, when a lawn squishes for days, or when water reaches a wall or patio base through the ground. Many yards need both: a solid line for roof water and a perforated line for groundwater, sharing one outlet. Pricing them together is usually cheaper than two separate visits, and the yard drainage page shows the combinations we build most.

1. Match the length and the route

   Confirm every bid uses the same run, drawn on your plat, with the same start point and the same outlet. A bid that stops 20 feet short of daylight is not cheaper.

2. Find the depths

   Look for a start depth and an end depth in inches, and a stated slope of at least 1 percent to the outlet.

3. Find the stone and the fabric

   The bid should name washed, open-graded stone and a non-woven geotextile liner. Crusher run or a sock-only pipe are reasons to ask questions.

4. Find the pipe

   Four inch rigid perforated PVC or dual-wall pipe, with cleanouts at the head and at bends. Roof water belongs in a separate solid line.

5. Find the outlet

   Daylight, pop-up emitter or an approved structure, with its location marked and confirmed lower than the trench bottom.

6. Find haul-off, utilities and restoration

   Clay disposal, Virginia 811 notice, private line locating, and whether sod or seed is included. These are the lines a low bid most often drops.

The per-foot ranges hold across our service area, but the conditions that push a job toward the top cluster by neighborhood. In the newer subdivisions of Ashburn, South Riding, Bristow and Gainesville, lots were mass graded and the topsoil stripped, so drains sit in dense compacted clay and often need to be deeper and wider to intercept water. In older neighborhoods in Arlington, Falls Church, Vienna, McLean and Annandale, the soil is often better but the drain has to thread between mature oak roots, old utility lines and narrow side yards, so more of the run is hand dug. In Alexandria and the eastern part of Fairfax County around Lorton and Springfield, marine clay holds water for weeks and daylight outlets are scarce on flat lots, which pushes systems toward longer solid pipe runs to the street.

Across all four counties, the fall and winter months are the best time to price and build a drain: the ground shows where water sits and crews are less booked than in spring. The french drain installation guide covers the build itself.

You turn a range into a number by having someone walk the yard after rain. A drainage site visit usually takes less than an hour. We watch where water sits, probe the soil to see how deep the saturated layer runs, find the lowest point on the lot and the nearest legal outlet, check every downspout and the sump discharge, measure gate widths and the route a machine would take, and look for marked and unmarked utilities. From that we write a scope that states the route on your plat, the start and end depths, the slope, the stone type and volume, the fabric, the pipe, the cleanouts, the outlet, the haul-off and the restoration. That written scope is the figure we stand behind and the only one worth comparing against other bids.

Bring a rough budget, photos of the yard during a storm, and your plat if you have it. The cost guide gathers planning ranges across our services, and the how it works page shows what happens between the visit and the finished trench. Request an on-site estimate and we will put a real number on your yard.