Yard Drainage in Molalla, Oregon: Fixing a Soggy Lawn

Fixing a Soggy Lawn in Molalla

If your Molalla lawn turns to a swamp every winter, the soil under your feet is usually the culprit. Out here in the Clackamas County foothills, the ground is heavy clay — it holds water like a bowl and drains painfully slowly. Add the long Oregon wet season and the sloped terrain that funnels hillside runoff toward homes and low spots, and you get lawns that stay soggy for days, grow moss instead of grass, and never quite firm up. Soggy lawns in clay country are a different problem than on the coast, and they call for a different fix.

The good news: clay-bound lawns can be drained. The right solution depends on why your particular lawn holds water, which is why a site assessment usually pays for itself.

Why Molalla Lawns Stay Wet

Most foothill lots have several of these working against them.

Heavy clay soil. Clay is the headline. Water can't move through it quickly, so rain that falls — or runoff that arrives — sits on or just below the surface and lingers. This is why deep drains alone often disappoint in Molalla: water can't reach them through the clay.

Hillside seepage. On sloped lots, water moves downhill underground and surfaces partway down as seeps and soggy bands. Runoff from uphill neighbors and pastures adds to it.

Negative grade and compaction. Lots that slope toward the house, or yards compacted by construction and equipment, trap water in low spots that never drain through the clay.

Long wet season. The foothills get a long, steady rainy season. Clay that's already saturated has nowhere to put more water.

Roof runoff. Downspouts dumping at the foundation concentrate water exactly where clay holds it longest.

Drainage Options That Work in Clay

Because clay resists deep drainage, the most effective fixes here are usually surface-first.

Surface regrading. Reshaping the surface to carry water away from the house and toward a downhill outlet is the cheapest, most durable first move in clay. Getting positive surface drainage right solves a large share of soggy-lawn problems where the soil won't drain downward.

Swales. A shallow, gently sloped channel — planted or rock-lined — guides surface water across the yard to a daylight point. Swales work especially well in clay because they move water over the surface rather than relying on it to soak down.

Curtain and interceptor drains. On sloped foothill lots, a drain placed uphill to intercept seepage before it reaches the lawn often outperforms a drain in the middle of the wet area — a key technique in Molalla.

Area drains and shallow French drains. Area drains with grates capture pooling at specific low spots; a shallow French drain can collect surface and near-surface water where it's concentrated. Both need a real outlet.

Downspout extensions. Getting roof water well away from the house removes a major source of saturation that clay would otherwise hold for days.

For the statewide cost picture, see our yard drainage cost guide for Oregon.

What Yard Drainage Costs in Molalla

Industry baseline ranges. Actual costs depend on lot size, soil, the solution chosen, access, and outlet distance. Clay and large rural lots can affect the total.

Solution	Industry Baseline Range
Surface regrading (small area)	$500–$3,000
Swale installation	$1,500–$5,000
French drain / curtain drain (yard run)	$2,500–$6,000
Area drains / catch basins (each, installed)	$500–$1,500
Downspout drain line + dry well	$1,000–$3,500

These are commonly reported starting figures, not quotes. Heavy clay, large lots, a long outlet run, or combined solutions push costs higher. A site visit is the only way to size the work.

Why a Molalla Site Assessment Matters

In clay country, the wrong solution wastes money — a deep French drain buried in clay can sit nearly dry while the lawn above it stays soaked, because water can't move through the clay to reach it. Walking the lot, reading the slope, finding where hillside water enters, and confirming a downhill outlet lets us recommend surface-first solutions that actually dry the lawn. On Molalla clay, matching the fix to the soil is everything.

Don't Forget the Outlet

Whatever the method, the water has to go somewhere. On sloped foothill lots, daylighting downhill is usually straightforward. On flatter benches, a dry well or a tie-in to a ditch or culvert may be needed. We respect setbacks and never route water onto a neighbor's property or into a creek buffer.

Get It Fixed

A wet lawn kills turf, breeds moss, undermines foundations, and steals the months you could be using your yard. Cojo Excavation & Asphalt helps Molalla homeowners diagnose and fix soggy lawns with solutions matched to clay-soil foothill conditions. Learn more about our excavation services and the full range of property drainage solutions in Oregon.