Excavation & Site Prep in Mill City, Oregon: 2026 Guide

Excavation and Site Prep in the Santiam Canyon

Mill City sits in steep, forested terrain where the North Santiam River runs through the canyon and Highway 22 connects the valley to the Cascades. Excavation work here is shaped by the land: slopes that have to be cut and benched, soils that hold water through a long wet season, and a canyon that saw major change after the 2020 Beachie Creek Fire. Whether you are clearing a rebuild site, prepping a pad for a new structure, or fixing a drainage problem that has plagued a property for years, the dirt work has to account for grade and water first.

Cojo Excavation & Asphalt runs excavation and site prep for Mill City and the surrounding canyon from our Willamette Valley base, an easy run up Highway 22. We bring the equipment and the local knowledge to handle canyon ground the right way.

What Excavation Covers in Mill City

Excavation is the work that happens before anything gets built or paved. In a canyon setting, the common scopes are:

• Site grading and leveling — Cutting and filling to create a stable, properly draining building pad or driveway base on sloped ground.
• Drainage and water management — French drains, swales, culverts, and surface grading to move water off a site. This is the single biggest issue in canyon properties.
• Utility trenching — Digging and backfilling for water, power, septic, and other lines, with proper compaction so the ground does not settle later.
• Land clearing — Removing brush, stumps, and debris, which is heavy demand on burned and rebuild parcels.
• Wildfire rebuild site prep — Clearing, grading, and pad preparation for properties coming back after Beachie Creek.

The variables that drive the scope and cost are laid out in our excavation cost in Oregon and site grading cost in Oregon guides.

Industry Baseline Pricing for Excavation

Excavation is the hardest service to price sight-unseen, because so much of the cost hides underground until you dig. What we can share is the industry baseline ranges the market reports. Treat these as a starting reference, not a quote. Canyon work with rock, steep grade, or long haul-off frequently exceeds them.

Industry baseline ranges. Actual cost depends on soil, rock, slope, access, haul-off, and project scope.

Scope	Industry Baseline Range
Site grading	$1.50–$4 per square foot
Land clearing (light to moderate)	$1,500–$5,000 per acre
Utility trenching	$10–$25 per linear foot
Drainage / French drain	$20–$40 per linear foot
Hourly excavator + operator	$150–$300 per hour
Haul-off / disposal	varies by volume and distance

The big unknowns in Mill City are rock and water. Canyon ground can hide ledge rock that slows digging, and the high water table in low spots near the river changes how you trench and drain. A site visit is the only way to scope it honestly.

Drainage Is the Canyon's Defining Problem

If there is one thing that separates a good Mill City excavation job from a bad one, it is water. The canyon gets soaked for months, and properties on a grade collect runoff from everything uphill. Poor drainage shows up as a soggy yard, a failing driveway base, water in a crawlspace, or erosion cutting through a site.

We design grading and drainage to move water deliberately: crown surfaces, cut swales, set culverts where flow concentrates, and install French drains where groundwater needs an exit. Done right at the excavation stage, this protects everything built on top of it, including any asphalt paving in Mill City that follows. Done wrong, or skipped, water finds the weak point and the repairs cost far more than the drainage would have.

Wildfire Rebuild Site Work

The Beachie Creek Fire cleared large stretches of the canyon, and rebuild site prep remains a steady need. These projects usually begin with clearing remaining debris and dead timber, then grading a stable pad, then trenching for the utilities the new structure will need. Because the ground may have shifted or eroded since the fire, we re-evaluate drainage from scratch rather than assuming the old layout still works. Getting the site prep right is the foundation, literally, for everything the rebuild puts on top of it.

Call Before You Dig: 811 and Permits

Every excavation job in Oregon starts with an 811 locate. Before we put a bucket in the ground, underground utilities get marked, which protects you, us, and the lines. We handle the locate as standard practice. Larger site work in Marion County can also trigger erosion-control and grading permits, and any work touching the Highway 22 right-of-way may require ODOT coordination. We know the local thresholds and fold the permitting into the project plan so it does not catch you off guard.

Why Mill City Property Owners Choose Cojo

Canyon excavation is not valley dirt work. The grades are steeper, the water is heavier, and the access can be tight. We bring the right machines and the judgment to read canyon ground, whether that is spotting a drainage problem before it becomes a foundation problem or recognizing when a slope needs to be benched rather than just cut. The run up Highway 22 from our base is routine, and we would rather scope a job accurately than lowball it and hit surprises.

Browse our completed grading and site work on the portfolio page, or learn more about our site prep and grading services across the canyon and valley.