French Drain Installation for Wet Yards and Soggy Soil

Yard water that heads straight for the house

A lawn that stays spongy into June, a puddle that sits beside the foundation for days after a storm, a patio that tilts water toward the back door: all of it is water in the wrong place. If it has nowhere else to go, it goes toward your foundation.

Portland’s soil is mostly clay and silt, and it takes water slowly. From October to May the top layer of soil fills, and every new rain adds water that sits on the surface or runs sideways through the soil toward the lowest point, which is often the house. On hillside lots, water moves downslope and collects at the foundation. On flat lots, it pools in place.

That water either soaks into the soil beside the wall and adds pressure on the foundation, or it enters through the wall, a window well or a crawl space vent. French drain installation gives it a path away from the house. It does not hold water back. It collects it and carries it to a place where it can go.

Portland yards hide a lot. A lawn that looks fine in August can hold six inches of water by February, and the water takes the same path every time. In Portland, where the ground is clay under a thin layer of topsoil, that path usually runs along the lowest line toward the house.

How we handle French drain installation, step by step

A French drain is simple in concept, and the details decide whether it works.

• Step 1: Read the water. We walk the property after looking at where water collects, where it runs and where it can safely be discharged, such as the street, a storm drain or a dry well.
• Step 2: Mark the route. The trench follows the path that catches the most water, with a continuous downhill slope to the discharge point.
• Step 3: Dig the trench. The trench is cut to the needed depth and width, and sod and soil are set aside for restoration.
• Step 4: Line with fabric. Filter fabric is laid in the trench so soil does not wash into the gravel and clog it over time.
• Step 5: Bed and lay the pipe. A layer of washed gravel goes in first, then perforated pipe with the holes facing down, set to a consistent slope.
• Step 6: Cover with gravel. More washed gravel covers the pipe, and the fabric is folded over the top.
• Step 7: Close and restore. The trench is capped with soil or topsoil, and the surface is restored. We run water through the drain to confirm it flows to the outlet.

Where a downspout empties into the problem area, we connect it to a solid pipe that bypasses the drain and discharges farther away.

We think of a French drain installation in three parts: the trench, the pipe and the outlet. A drain with good pipe and no outlet is just a buried pond. The outlet is where most do-it-yourself drains fail, and it is the part we plan first.

Signs you need a French drain

• Standing water in the yard days after rain
• Soggy or mossy lawn areas that never dry out
• Water pooling beside the foundation or against basement walls
• Mud or erosion running toward the house on a slope
• Wet crawl space or window well after storms
• Downspouts that empty onto flat ground near the house
• Patio or walkway settling or heaving from saturated soil
• A basement that leaks along the wall facing a wet yard

What affects the cost of French drain installation

A short drain along one wall costs far less than one that wraps the house. These are the main factors:

• Length and depth: A longer or deeper trench means more digging, pipe and gravel.
• Soil and obstacles: Rock, roots, utilities and tight spaces slow the work.
• Surface to restore: Lawn is simple. Pavers, concrete and landscaping beds take more to put back.
• Discharge point: Daylight, a storm drain or a dry well each need different work.
• Slope: Flat lots may need a pump if there is no natural downhill outlet.

For exact pricing on your yard, call (971) 772-3963.

When sump pump installation is the better fit

A French drain moves water by gravity, which means it needs a downhill outlet. On a flat lot, or where the discharge point is higher than the drain, gravity cannot carry the water out. In that case a sump pump installation collects the water in a basin and pumps it to the discharge.

The two also work together. A French drain brings water to a sump, and the pump sends it away. If the water is entering your basement or crawl space rather than pooling in the yard, a sump system inside the structure is usually the more direct fix. We look at where the water goes and recommend what fits.

Why acting before the next rainy season matters

Portland yard water is easy to ignore in summer, and it is the same water that shows up in your basement in December. A drain installed before the wet season has time to settle, and the gravel and fabric get established before heavy flow.

Wet soil beside the house adds weight and pressure to the foundation wall and feeds moisture into the crawl space. Erosion on slopes carries soil away from under walkways and slabs, and the damage grows each winter.

Digging in dry ground is also easier. In winter the trench fills with water, the soil turns to mud and restoration is harder. Late summer is the best time to put a drain in.

French drain installation FAQ

How deep does a French drain need to be?

It depends on the problem. A surface drain for a soggy yard is relatively shallow, and a drain along a foundation goes down to the footing. We set the depth after looking at the site.

Will a French drain clog?

With filter fabric and washed gravel, it should stay clear for many years. Without fabric, soil washes in and the drain clogs. Roots can also enter, so we avoid running drains near large trees where possible.

Where does the water go?

To a place where it can legally and safely discharge: daylight on a slope, a storm drain connection, a dry well or a pumped outlet. We will explain the options for your lot.

Can a French drain fix a wet basement?

It can reduce the water pressing against the wall and often helps, especially when the problem is surface and shallow groundwater. For water already entering the basement, an interior drain and sump may also be needed.

How long does installation take?

A typical residential drain takes one to three days, depending on length, depth and the surface that has to be restored.

Can I use a French drain to fix a wet crawl space?

It can help by lowering the water that reaches the foundation, but it will not stop all water entering the crawl space. Standing water under the house usually also needs an interior drain and a pump. A French drain installation is the outside half of that fix.

How far from the house should the drain be?

It depends on the lot. Along a foundation, it sits a few feet out and down to the footing. To intercept slope runoff, it goes across the hill farther away. We lay it out on site after seeing where the water goes.

Call (971) 772-3963 and tell us where the water collects. We will walk the property and plan a drain that fits.