Seattle · King County
French Drain Installation in Seattle, WA
French drains, curtain drains and downspout tightlines in Seattle that collect water before it reaches the house and carry it to an approved outlet. Serving Lake City, Wedgwood, Maple Leaf and Northgate.
Why Seattle yards hold water
Glacial till and outwash across most of the city, with landslide-prone slopes and soft fill in some lowlands. That is the root of most soggy lawns, wet crawlspaces and ponding patios we see in Seattle: water that cannot soak in perches on the hard layer and runs to the lowest point.
Hills and ridges between Puget Sound and Lake Washington, with steep slopes and ravines through many neighborhoods. Slopes push water onto the next lot down, and flat ground leaves it nowhere to go, so the drain route and the grade around the house matter as much as the pipe.
Thornton Creek, Piper's Creek, the Sound and lake shorelines carry critical-area rules, and Seattle maps Environmentally Critical Areas for steep slopes and landslide-prone ground. Where a drain can legally discharge depends on these features, so we plan the outlet first and the trench second.
Common french drains projects in Seattle
Soggy lawns
French drains for Seattle lawns that stay wet all winter because water perches on the hard till below.
Wet crawlspaces
Curtain and footing-side drains that keep water away from foundations and crawlspaces in Lake City and Wedgwood.
Downspout tightlines
Roof water carried in solid pipe away from Seattle foundations to an approved outlet.
Hillside water control
Curtain drains across Seattle slopes that stop water before it sheets over a bank or onto the next lot.
Flat-ground drainage
Drains, catch basins and ditch work for flat, low Seattle properties where water has nowhere to go.
What our french drains work in Seattle covers
- French Drains
- Curtain Drains
- Downspout Tightlines
- Catch Basins
- Yard Regrading
- Material Delivery
Permits & Rules
Drainage rules in Seattle
Small yard drains usually do not need a permit, but connecting to a storm system, working near a stream or wetland, or changing how water leaves the property can need approval from the Seattle Department of Construction and Inspections (SDCI). Outside city limits, the King County Department of Local Services handles it.
Water can go to an existing storm system, a dispersion area or an infiltration trench where the soil allows. It cannot be pointed at a neighbor or dumped over a slope.
Cost & Timing
What affects the cost of french drains in Seattle
We do not publish flat prices because no two Seattle sites are the same. These are the things that move the number most here.
Slope and access
Steep Seattle lots take smaller machines, more careful staging and sometimes engineering, which adds time compared with flat, open ground.
Tight lots
Narrow side yards and alley access in Seattle mean compact equipment and shorter truck loads. We plan it so it costs less than it could.
Soft ground
Where Seattle soils are soft or wet, over-excavation, fabric and imported rock are often part of the job, and we price that in up front.
Buffers and permits
Work near Seattle's rivers, creeks, lakes or shoreline can need permits and limits on where machines go. That affects scope and schedule more than price.
Haul-off and disposal
How much material leaves the site, and what it is, drives cost. Our own trucks keep that predictable on Seattle jobs.
When to schedule french drains in Seattle
French Drains in Seattle goes best in the drier months, when soil compacts properly and trenches stay open. Wet-season work is doable with erosion control and the right material, and we plan for it in the quote.
Seattle's till soils hold water through the winter, which is when drainage problems show up. That is a good time to see where water goes, and the dry season is the time to fix it.
Where We Work
Drainage work across Seattle
In Seattle, DirtRaptor mostly works the north end, from Lake City and Wedgwood to Greenwood and Ballard. Seattle lots are tight, access is often by alley, and the city has detailed rules for trees and steep slopes.
We install French and curtain drains, catch basins and downspout tightlines across Lake City, Wedgwood, Maple Leaf, Northgate, Greenwood, Ballard, View Ridge and Magnolia. Craftsman and mid-century homes on small lots, with a lot of ADU, townhome and redevelopment work.
Drain rock, fabric and pipe are delivered on our own trucks, and the excavated soil is reused for regrading or hauled away.
We also do french drains nearby in Kirkland, Shoreline, Lake Forest Park and Kenmore. See everything we do in Seattle, read our full guide to french drains, or browse all service areas.
Why DirtRaptor
Why Seattle owners call us for french drains
Owner on the machine
On Seattle jobs you talk to the person who walks the site, writes the quote and runs the equipment.
Trees and dirt, one crew
If trees are in the way of your Seattle project, we take them down ourselves instead of waiting on a separate tree service.
Our own trucks
Haul-off and deliveries run on our schedule along I-5 and SR 99, not a subcontractor's.
Built for slopes
We plan machine placement, drainage and erosion control for Seattle's sloped ground before we start.
How a french drains job runs
- 01
Find the Water
- 02
Plan the Outlet
- 03
Trench, Fabric, Rock & Pipe
- 04
Backfill & Grade
Real Jobs
Recent DirtRaptor work near Seattle
Demolition · Edmonds, WA
Driveway Removal & Concrete Prep
Tearing out an old blacktop driveway and prepping the ground for a new concrete pour — broken material hauled off, base left clean and ready.
Demolition · Everett, WA
Condemned 100-Year-Old Shed Teardown
A 100-year-old shed, condemned and unsafe, brought down and hauled off — the site left graded flat and clean.
Questions
French Drain Installation in Seattle: FAQs
Will a French drain fix my wet yard in Seattle?
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Often, especially combined with regrading. Glacial till and outwash across most of the city, with landslide-prone slopes and soft fill in some lowlands. A drain plus better grading handles most of what that causes.
Where can drainage water go in Seattle?
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To an approved outlet: a storm system, a dispersion area or an infiltration trench where the soil allows. Thornton Creek, Piper's Creek, the Sound and lake shorelines carry critical-area rules, and Seattle maps Environmentally Critical Areas for steep slopes and landslide-prone ground.
Do I need a permit for a French drain in Seattle?
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Usually not for a small yard drain. Storm connections or work near streams, wetlands or slopes can need approval from the Seattle Department of Construction and Inspections (SDCI). We confirm before digging.
How much does french drains cost in Seattle?
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It depends on the site, so we quote after a free site walk rather than guessing on the phone. The biggest drivers in Seattle are usually slope and access, tight lots, soft ground. You get a written number with inclusions and exclusions spelled out.
When is the best time to schedule french drains in Seattle?
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French Drains in Seattle goes best in the drier months, when soil compacts properly and trenches stay open. Wet-season work is doable with erosion control and the right material, and we plan for it in the quote.
Can you work on a tight Seattle lot with alley access?
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Yes. Compact tracked machines and our own trucks let us dig, demo and haul off from alley access, with the alley protected and kept open as much as possible.
Do you handle site prep for ADUs in Seattle?
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Yes. ADU site prep usually includes small demolition, tree work, excavation for the foundation and utility trenching. We do it all with one crew.
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.
Ready for a real number in Seattle?
Send the address and a few photos. We walk the site for free and come back with a written quote.
