Snohomish · King · Skagit · Pierce
French Drains & Yard Drainage
French drains and curtain drains that collect water before it reaches the house and carry it to an approved outlet.
What a French Drain Actually Does
A French drain is a trench lined with filter fabric, filled with drain rock and fitted with a perforated pipe. Water that would otherwise soak a yard, pond against a foundation or seep into a crawlspace flows into the trench, into the pipe, and away to somewhere it can safely go.
Across much of Snohomish and north King County, the ground under the topsoil is dense glacial till. Water cannot soak into it, so it perches on top and runs toward the lowest point, which is often a house, a patio or a low corner of the yard. That is why so many lawns here stay soggy all winter, and why French and curtain drains are some of the most effective fixes we install.
The part most people miss is the outlet. A drain is only as good as where it ends. Water has to go to an existing storm system, a dispersion area or an infiltration trench where the soil allows, never pointed at a neighbor or dumped over a slope. We plan the outlet first and the trench second.
Worth Knowing
Most wet-crawlspace and soggy-yard problems in this region are caused by surface and perched water, not a high water table. That is good news: it means grading and a properly placed drain usually fix it.
The Process
How a Drainage Job Runs
Good drainage starts with watching where the water goes.
Find the Water
We walk the site, look at slopes, downspouts and wet spots, and work out where the water is coming from and where it can legally go.
Plan the Outlet
The discharge point is chosen first: storm system, dispersion area or infiltration trench, depending on the site and local rules.
Trench, Fabric, Rock & Pipe
The trench is dug to grade, lined with fabric, bedded with drain rock and fitted with perforated pipe sloped to the outlet.
Backfill & Grade
The trench is backfilled and the surface regraded so water moves to the drain instead of the house.
Scope
What Drainage Work Covers
Most drainage fixes combine a drain with some regrading.
French Drains
Perforated pipe in a fabric-lined rock trench that collects water across a yard or along a foundation.
Curtain Drains
A drain across a slope that intercepts water before it reaches the house or a low spot.
Downspout Tightlines
Solid pipe that carries roof water away from the foundation to an approved outlet.
Catch Basins
Surface inlets that collect water from patios, driveways and low corners.
Yard Regrading
Reshaping the ground so it falls away from the house, often the cheapest part of the fix.
Material Delivery
Drain rock, fabric and pipe delivered and placed by our own crew and trucks.
Why Us
Why DirtRaptor for French Drain Installation
Owner On The Machine
You talk to the person doing the work, not a salesperson who has never seen your site.
Arborist-Led Tree Work
Trees and dirt work handled by one company on one mobilisation — rare in this trade.
Our Own Trucks
Haul-off is not a marked-up subcontractor line. It is a truck we own and a schedule we control.
Since 2019
Years of Pacific Northwest ground, wet seasons, and county permit desks.
Honest Exclusions
Rock, groundwater and buried debris are excluded in writing, not discovered as a surprise invoice.
Free On-Site Quotes
A real number from a real site walk, not a range guessed over the phone.
Pricing
What Drives Drainage Cost
Drainage is priced on length, depth and where the water can go.
Length & Depth
How far the drain runs and how deep it needs to be set drive most of the excavation and material cost.
The Outlet
A nearby storm connection is simple. A long run to a dispersion area or an infiltration trench adds scope.
Access & Restoration
Working around patios, landscaping and tight side yards takes more care, and lawn and bed restoration adds time.
The fastest route to an accurate number is a site walk. Quotes are free and there is no obligation.
Get My Free QuoteQuestions
Frequently Asked Questions
Will a French drain fix my wet yard?
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Often, especially combined with regrading. Most wet yards in this region are caused by water perching on glacial till, which a drain and better grading handle well. We look at where the water comes from before recommending a fix.
Where does the water from a French drain go?
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To an approved outlet: an existing storm system, a dispersion area, or an infiltration trench where the soil allows. It cannot be pointed at a neighbor or over a slope.
Do I need a permit for a French drain?
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Small yard drains usually do not, but connecting to a storm system, working in a critical area or changing how water leaves the property can. We confirm with your city or county before we dig.
How long does a French drain last?
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A properly built drain with filter fabric and clean drain rock can last for decades. Drains without fabric clog with silt much sooner, which is why we never skip it.
What is the difference between a French drain and a curtain drain?
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They are built the same way. A curtain drain is placed across a slope to intercept water before it reaches the house; a French drain collects water where it already pools.
Do you install French drains in King County?
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Yes, across north King County including Bothell, Kenmore, Woodinville, Kirkland, Redmond, Sammamish and Shoreline.
Can a French drain connect to the city storm system?
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Sometimes, with approval. Each city and county has its own rules on storm connections. We confirm what is allowed before planning the outlet.
Question not answered here? Send us the details and we will come back to you.
Often Booked Together
Related Services
Combining scopes on one mobilisation is almost always cheaper than booking them separately.
Grading & Drainage
Retaining walls, RV and equipment pads, and drainage correction that actually moves water away from the structure.
Retaining Wall Contractor
Block and rock retaining walls that hold back sloped yards and driveways, built on a compacted base with drainage behind them.
Excavation Contractor
Foundation pits, footings, trenching, utilities, construction roads and building pads — dug to spec, inspected, and signed off.
Across the Region
Why Yards Stay Wet Here
Much of south Snohomish and north King County sits on dense glacial till, which water cannot soak into. Yards in Lynnwood, Mill Creek, Bothell, Brier, Sammamish and similar upland neighborhoods often stay soggy all winter because water perches on top of that hard layer.
In the river valleys around Snohomish, Monroe and Arlington, high groundwater and flat ground make the outlet the hard part. On the bluffs in Edmonds and Mukilteo, controlling water so it never sheets over a slope is the priority.
Where we do french drain installation
In Snohomish County: Everett, Lynnwood, Bothell, Mill Creek, Mountlake Terrace, Edmonds, Mukilteo, Marysville, Snohomish, Lake Stevens, Monroe, Arlington, Brier, plus Stanwood, Granite Falls, Sultan, Gold Bar, Woodway.
In King County: Woodinville, Kenmore, Kirkland, Redmond, Bellevue, Shoreline, Lake Forest Park, Sammamish, Duvall, Seattle, plus Issaquah, Snoqualmie, North Bend, Carnation, Renton, Newcastle, Mercer Island.
In Skagit County: Mount Vernon, Burlington, Sedro-Woolley, Anacortes.
In Pierce County: Tacoma, Puyallup, Bonney Lake, Gig Harbor.
French Drain Installation Across Four Counties
Serving Snohomish, King, Skagit and Pierce County, Washington. Send photos and a rough scope and we will come back with a real number.
