Excavation & Site Prep in Gaston, Oregon: 2026 Guide

Excavation & Site Prep in Gaston, Oregon

Most paving and building projects start with dirt work, and out in the rural west end of Washington County there is plenty of it. Gaston properties tend to be acreage: farms, rural homesites, shops, and outbuildings that need grading, drainage, utility trenching, and land clearing before anything gets built or paved. Get the excavation wrong and every layer above it suffers, from a cracking driveway to a flooding outbuilding.

Cojo Excavation & Asphalt handles site prep across Gaston and the surrounding county from its Willamette Valley base. Excavation is the unglamorous foundation of almost everything else we do, and on valley soils it deserves real attention.

What Excavation Costs in Gaston

Excavation pricing is harder to pin to a chart than paving because every site is different. Soil type, haul-off distance, access, and the volume of material moved all swing the number. The ranges below are industry baselines. Actual costs in the current market frequently run higher, and your real number depends entirely on the site.

Industry baseline ranges shown below. Actual costs vary widely and are often higher based on soil conditions, volume, access, haul-off, and the scope of work.

Service	Industry Baseline Range
Site grading (per sq ft)	$0.50–$2.00
Excavation / digging (per cubic yard)	$50–$200
Utility trenching (per linear foot)	$10–$30
Land clearing (per acre)	$1,500–$6,000
Drainage / French drain (per LF)	$25–$60

These baselines move fast with site conditions. Rocky ground, a high water table, or limited equipment access can push real costs well above the range. For a deeper breakdown, see our excavation cost in Oregon and site grading cost in Oregon guides.

Valley Soils and Drainage

Western Washington County soils are clay-heavy and hold water, which is the central excavation challenge in Gaston. During the wet season, poorly drained ground stays saturated for months. That standing water undermines foundations, floods crawl spaces, turns gravel drives to mud, and rots out the sub-base of any asphalt placed on top of it.

Good site prep in the valley is really about water management: grading the site so water sheds away from structures, cutting drainage paths, and installing French drains or culverts where the land traps water. On many Gaston jobs the drainage plan is the most important part of the work, even when the customer originally called about something else entirely.

Washington County Permits and Erosion Control

Excavation in the county comes with a regulatory layer that depends on scope and location:

• Grading permits are generally triggered when you move soil above a threshold volume or disturb a certain area, especially on slopes.
• Erosion and sediment control rules apply on most disturbance projects to keep silt out of streams and ditches, which matters in the Tualatin River drainage around Gaston.
• Floodplain and stream-setback rules add review on lowland properties near waterways.
• Stormwater management can come into play when you create new impervious surface.

We work through the applicable county requirements as part of the job rather than leaving you to navigate the permit counter alone.

Always Call 811 Before Digging

Before any excavation, Oregon law requires marking underground utilities through the 811 locate system. On rural Gaston properties this is genuinely important, because you can have buried power, water, gas, septic lines, and old farm infrastructure that nobody documented. Hitting a gas or power line is dangerous and expensive. We file the locate request and wait for the marks before equipment touches the ground. It is not optional and it is not a formality.

Excavation Feeds Everything Else

Site prep is the first step in most larger projects. A driveway is only as good as the sub-base under it, so excavation and grading set up the asphalt paving in Gaston work that follows. Drainage corrections often prevent the very driveway repair in Gaston problems that bring people to us in the first place. Doing the dirt work right the first time is almost always cheaper than fixing failures later.

Why Hire a Local Excavation Contractor

Excavation rewards local knowledge more than almost any trade. A contractor who understands valley clay, the county permit picture, and where water wants to go on your kind of property will save you from the expensive surprises. We do site prep throughout Washington County, and we bring the equipment and the drainage experience that rural Gaston sites demand.