If you need French drain installation in Woodland, WA, the first question is not how long the trench will be but where the water goes once it is in the pipe. A French drain is a trench of clean drain rock wrapped in filter fabric, with a perforated pipe in the bottom that collects groundwater and carries it downhill. It only works with steady fall and a real outlet, so we pick the outlet first and build the drain back from it.
Bogar Landscaping builds landscape drainage for backyards that stay soggy from November to May, new-construction lots on compacted fill, and acreage where water sheets across the pasture and pools by the shop. The same crew grades, lays sod and builds walls, so your yard gets put back together after the drain goes in.
Landscape Drainage Solutions We Build in Woodland, WA
Most wet yards need more than one fix. A typical drainage job draws from this list:
- Diagnosis in the wet. We walk the yard, note where water stands, where it enters and where the true low point is, and check the gutters and downspouts while we are there.
- French drains. Perforated pipe in a fabric-wrapped trench of drain rock, run at a steady fall to a daylight outlet, a dry well, or a storm connection the city or county allows.
- Curtain drains. A French drain set across the uphill side of a yard to catch groundwater seeping downslope before it reaches the lawn or the foundation.
- Swales and regrading. Shallow grassed channels and reshaped grades that move surface water before it soaks in. Larger reshaping is covered on our yard grading and erosion control page.
- Roof water separation. Downspouts piped in solid pipe to their own outlet, so roof water does not flood the yard drain. See downspout drainage and catch basins.
- Dry creek beds. River rock channels that carry water across a yard in the open and look like they belong there.
- Restoration. Topsoil, seed or new sod, and fresh bark dust in the beds, so the trench line disappears.
Signs Your Yard Needs a Drainage Fix
Water problems announce themselves, usually in January. Call when you notice:
- Puddles that last a day or more after the rain stops, in the same spots every year.
- A lawn that squishes underfoot or holds footprints well into spring.
- Moss spreading across the grass, worst in the low spots and the shade. Our lawn moss removal page covers what to do once the water is handled.
- Water in the crawl space or a damp smell under the house after storms.
- A retaining wall that weeps mud or starts to lean, a sign of water trapped behind it. See our retaining wall page.
How We Install a French Drain, Step by Step
- Request a utility locate. Washington law requires notice to the locate service at least 2 full business days, and no more than 10, before digging, with the dig area marked in white. We mark the route and wait for the paint and flags.
- Pick the outlet and set the grade. The discharge point comes first. Then we take elevations back up the route so the pipe falls the whole way. Cost guides call for at least 1 percent of fall, about an inch every 8 feet.
- Dig the trench. Depth follows the water. A drain catching groundwater perched on clay goes deeper than one drying a soggy lawn surface.
- Line it with filter fabric. Fabric keeps silt and clay from migrating into the rock and plugging it, which is how most French drains die in our soils.
- Place drain rock and pipe. Clean, washed drain rock, then perforated pipe, then more rock, with the fabric folded over the top.
- Build the outlet. A daylight outlet with a rock pad or grate, a dry well, or a tie-in the jurisdiction approves. Long runs get a cleanout.
- Test and restore. We run water through the line and watch the outlet, then cap the trench with soil and put the lawn or beds back.
French Drain, Curtain Drain, Swale or Dry Well: Picking the Right Fix
Each tool handles a different kind of water. The right one depends on whether the water comes across the surface, up through the ground, or off your roof.
| Option | What it handles | Best for | Limits |
|---|---|---|---|
| French drain | Groundwater and saturated soil | Lawns that stay soggy, wet strips along a foundation or wall | Needs steady fall and an outlet lower than the trench |
| Curtain drain | Groundwater moving downhill | Yards below a slope or below a neighbor's higher lot | Must sit uphill of the wet area to intercept the water |
| Swale | Surface runoff | Sheet flow across lawns and acreage | Takes some width; still needs somewhere to send the water |
| Dry well | Collected water with no outlet | Flat lots with no lower ground nearby | Only works where the subsoil absorbs water; high winter groundwater limits it |
| Dry creek bed | Surface and roof water | Moving water across a yard in the open | Carries water but does not dry out saturated soil |
On many local jobs the answer is a combination: a swale for the surface, a French drain for the soggy middle, and the downspouts piped on their own line.
Why Yards in Woodland and Southwest Washington Stay Wet
Rain is the start of it. NOAA's 1991 to 2020 normals put Longview, just up I-5, at 48.12 inches of precipitation a year, with measurable rain on about 192 days. Most of it falls from November through March, when grass is barely growing and the ground is already full.
Soil does the rest. Much of the low ground in the Woodland Bottoms and the Longview lowland is Caples silty clay loam: slow permeability, 35 to 45 percent clay, and a seasonal water table 1.5 to 2.5 feet down from November to April. Up on the terraces, soils such as Gee silt loam take water well at the surface but slow to very slow permeability in the lower subsoil, so water perches on the clay and sits in the root zone.
New subdivisions add a third layer. Builders strip topsoil and compact fill with heavy equipment, and the finished lawn sits on ground that sheds water like a driveway. On the moss-covered backyard in our photos, that combination had turned the lawn into a winter pond. We reshaped the grade so water runs off the lawn, brought in fresh soil and laid sod over it.
What Affects the Cost of French Drain Installation in Woodland, WA
National cost guides put exterior French drains at roughly $10 to $100 per linear foot, with typical projects landing between $2,800 and $6,500. Those are third-party national figures, not our prices. What moves your number:
- Length and depth of the trench. Deeper drains move more soil and take more rock.
- Distance to a usable outlet. Daylighting into a ditch at the property line costs far less than a long pipe run or a dry well.
- Access. Open yards fit a mini excavator. Fenced backyards and narrow side yards mean hand digging.
- Obstacles. Tree roots, sprinkler lines, buried utilities and rock all slow trenching.
- Restoration and related fixes. Sod, beds, downspout piping or regrading done at the same visit.
Your written estimate breaks out each piece, so you can see what the drain costs and what the cleanup costs.
Keeping Your Drainage System Working
- Keep roof water out of the perforated line. Downspouts belong on their own solid pipe.
- Check the outlet after the first big fall storms and clear leaves and sediment off grates and rock pads.
- Flush through the cleanout with a garden hose if flow at the outlet drops off.
- Keep the outlet open. Do not bury it under soil or bark dust, and keep willows and other water-seeking trees off the line.
