On HomeGuide's national 2026 pages, a typical yard drainage system costs $1,000 to $4,000 and a French drain $10 to $35 a foot. In Clark County, drainage is the most common reason homeowners call an excavator, because the rain lasts from fall to spring.
We did not set the dollar figures on this page: they are national ranges from HomeGuide. In Clark County, wet-season clay, trees, slope, groundwater and haul distance are what push a real job up or down. Figures checked October 2026.
How do I fix standing water in my yard?
Fix standing water by giving it a route: regrade the low spot so it falls to a swale, a ditch or the street, add a French drain where water moves under the surface, or use a drywell where the soil is sandy gravel. On north county clay, grading and a drain to a real outlet come first, because water will not soak in.
My back yard is soggy for months every winter. What fixes it?
A yard stays soggy for months when it sits on slow-draining clay, is graded flat, or collects water from higher lots. Re-sloping the yard and adding a subsurface drain or a curtain drain to an outlet fixes most of them. Topsoil on top of wet clay only adds a soft layer.
Why does water collect against my foundation and crawl space?
Water collects against the foundation when the soil slopes toward the house, planters and bark have built the grade up at the wall, or downspouts drop roof water at the footing. Months of rain then soak the crawl space. Regrading, solid downspout lines and a footing drain take care of most homes.
What does a French drain cost?
A yard French drain runs $10 to $35 per linear foot, or $500 to $8,800 installed, on HomeGuide's French drain page. A crawl space drain costs $20 to $40 per foot and an interior basement drain $40 to $85, both common needs in older Vancouver and Portland homes.
| Length | Outside drain | Inside basement drain |
|---|---|---|
| 50 ft | $500 to $1,800 | $2,000 to $4,300 |
| 100 ft | $1,000 to $3,500 | $4,000 to $8,500 |
| 200 ft | $2,000 to $7,000 | $8,000 to $17,000 |
What does a curtain drain or a drain around the house cost?
By HomeGuide's figures, a curtain drain runs $10 to $35 a foot, roughly $1,500 to $8,800, and a perimeter drain along the footing $30 to $90 a foot, about $1,200 to $4,500 per side. Curtain drains above the house are the usual answer on sloped lots in Camas, Salmon Creek and Washougal.
French drain or dry well: which do I need?
A French drain carries water to an outlet; a drywell stores it underground until it soaks away. HomeGuide prices a drywell at $300 to $1,500. Drywells can work well in Vancouver's sandy flood gravels, but on clay they fill and stay full, so we check the soil first.
What does a swale cost, and should I use a swale or a catch basin?
For a swale, plan on $250 to $1,000 by HomeGuide's drainage page. A swale is a shallow grassy or rock-lined channel that carries water across the surface; a catch basin is a grated box at a low spot that sends water into a pipe. Use a catch basin where a patio or a narrow side yard leaves no room for a swale.
How deep should a drain or ditch be?
A swale is a few inches deep. A French drain is usually 18 to 24 inches deep, and a footing drain sits at the bottom of the footing. Every drain needs a steady fall to an outlet that sits lower than the wet area and stays open through the rainy season.
Can my downspouts be buried and run away from the house?
Yes. Solid pipe can carry roof water from each downspout to a drywell, a swale or the street where allowed. HomeGuide prices buried downspout lines at $150 to $350 each. Many local rules ask for roof water to be handled on the lot, so we check the outlet before digging.
Water from my neighbor's yard drains onto mine. What can I do?
Start with a calm talk with your neighbor and photos taken during a long rain. Washington law on runoff between neighbors depends on the facts, so for a real dispute, see a local attorney; this is general information, not legal advice. On your side, a curtain drain or a swale along the property line can catch the water and send it to your own outlet.
Can excavation fix a wet basement or a flooded crawl space?
Yes, when the water comes from outside. Regrading, curtain drains and an exterior drain at the footing keep water away from the walls, and HomeGuide lists basement waterproofing at $6,000 to $18,000. If the wall itself is cracked, that is work for a foundation contractor, and we can open the ground for them.
Tell us about your project and we will come look at the ground, then send the scope and the price in writing. Call or text (360) 276-9112.